Logika hry

Už umíš vykreslit hada ze seznamu souřadnic. Hadí videohra ale nebude jen „fotka“. Seznam se bude měnit a had se bude hýbat!

Rozhýbejme hada

Tvůj program teď, doufám, vypadá nějak takhle:

import pyglet

TILE_SIZE = 64

snake = [(1, 2), (2, 2), (3, 2), (3, 3), (3, 4), (3, 5), (4, 5)]
food = [(2, 0), (5, 1), (1, 4)]

red_image = pyglet.image.load('apple.png')
snake_tiles = {}
for start in ['bottom', 'end', 'left', 'right', 'top']:
    for end in ['bottom', 'end', 'left', 'right', 'top', 'dead', 'tongue']:
        key = start + '-' + end
        image = pyglet.image.load('snake-tiles/' + key + '.png')
        snake_tiles[key] = image

window = pyglet.window.Window()

@window.event
def on_draw():
    window.clear()
    pyglet.gl.glEnable(pyglet.gl.GL_BLEND)
    pyglet.gl.glBlendFunc(pyglet.gl.GL_SRC_ALPHA, pyglet.gl.GL_ONE_MINUS_SRC_ALPHA)
    for x, y in snake:
        before = 'end'     # (Tady případně je nějaké
        after = 'end'      #  složitější vybírání políčka)
        snake_tiles[before + '-' + after].blit(
            x * TILE_SIZE, y * TILE_SIZE, width=TILE_SIZE, height=TILE_SIZE)
    for x, y in food:
        red_image.blit(
            x * TILE_SIZE, y * TILE_SIZE, width=TILE_SIZE, height=TILE_SIZE)

pyglet.app.run()

Zkus těsně nad řádek pyglet.app.run doplnit funkci, která se bude volat každou šestinu vteřiny a přidá hadovi políčko navíc:

def move(dt):
    x, y = snake[-1]
    new_x = x + 1
    new_y = y
    new_head = new_x, new_y
    snake.append(new_head)

pyglet.clock.schedule_interval(move, 1/6)

Funguje? Tak do téhle funkce ještě přidej del snake[0], aby had nerostl donekonečna. Víš co tenhle příkaz dělá? Jestli ne, koukni znovu na poznámky k seznamům!

Zvládneš funkci upravit tak, aby had lezl nahoru?

Jestli ano, gratuluji! Zvývá směr hada ovládat šipkami na klávesnici, a většina hry bude hotová!

Třída pro stav

Než ale uděláme interaktivního hada, zkusíme trošku uklidit. Program se nám rozrůstá a za chvíli bude složité se v něm vyznat.

Stav hry máme zatím ve dvou seznamech: snake a food. Časem ale bude podobných proměnných víc.

Abychom je měli všechny pohromadě, vytvoříme pro stav hry třídu.

Na všechno, co se ve hře může stát, nadefinujeme metody. Zatím budou dvě: začátek hry a pohyb hada.

Na začátku hry se zavolá metoda __init__. Má trochu divné jméno se dvěma podtržítkama na každé straně. Podle toho Python ví, že tahle metoda je speciální a se má volat při vytvoření objektu.

Metoda __init__ nastaví celý stav hry jako atributy. Stav hry je všechno, co potřebujeme o hře vědět a může se to časem měnit. V našem případě to zatím budou souřadnice hada a jídla.

Metoda move, kterou budeme volat při každém „tahu“ hry, je bude tyhle atributy měnit.

Pro funkčnost, kterou zatím náš had umí, bude třída se stavem vypadat následovně. Přidej ji do programu hned za nastavení konstant.

class State:
    def __init__(self):
        self.food = [(2, 0), (5, 1), (1, 4)]
        self.snake = [(0, 0), (1, 0)]

    def move(self):
        old_x, old_y = self.snake[-1]
        new_x = old_x + 1
        new_y = old_y
        new_head = new_x, new_y
        self.snake.append(new_head)
        del self.snake[0]

Použij prosím pro třídu jméno State a i atributy pojmenuj podle materiálů (snake, food, a později i další). Bude se ti to hodit.

Všimni si, že metody berou argument self. To označuje konkrétní objekt, stav hry se kterým metoda pracuje nebo který mění. Ke všem atributům přistupují pomocí tečky – self.jméno_atributu.

Tak, máme třídu se stavem. No jo, ale jak ji teď použít?

Na to potřebuješ ještě několik změn:

  • Nastavování seznamů snake a food (mimo třídu) zruš; místo nich nastav jedinou proměnnou state na nový stav:

    state = State()

  • Místo snake a food ve funkci on_draw použij state.snake a state.food – atributy našeho stavu.

    Všimni si že tady se nepoužívá self, což je jméno které používají jen metody v rámci třídy. Jinde musíš pojmenovat konkrétní objekt, se kterým pracujeme.

  • Funkci move přepiš tak, aby jen volala metodu state.move:

    def move(dt):
    state.move()

    Všimni si že ani tady se nepoužívá self.

  • Vykreslování hada z funkce on_draw přesuň do nové metody draw:

    class State:
  ...

  def draw(self):
      for x, y in state.snake:
          ...
      for x, y in state.food:
          ...
...

@window.event
def on_draw():
    window.clear()
    pyglet.gl.glEnable(pyglet.gl.GL_BLEND)
    pyglet.gl.glBlendFunc(pyglet.gl.GL_SRC_ALPHA, pyglet.gl.GL_ONE_MINUS_SRC_ALPHA)
    state.draw()

    Všimni si že ani tady se nepoužívá self.

Povedlo se? Funguje to jako předtím? Pro kontrolu můžeš svůj program porovnat s mým (ale nejde o jediné správné řešení):

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Ovládání

Nyní k onomu slíbenému ovládání. Respektive nejdřív k změnám směru.

Had ze hry se plazí stále stejným směrem, dokud hráč nezmáckne klávesu. Had z naší ukázky se plazí doprava. Jestli jsi to ještě neudělala, zkus zařídit, aby se místo toho plazil nahoru.

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A co dolů?

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Aby si had „pamatoval“ kam se zrovna plazí, je potřeba mít směr jako součást stavu hry. Uložme ho tedy do atrubutu jménem snake_direction.

Co tam ale přesně uložit? Jak reprezentovat směr v Pythonu – pomocí čísel, n-tic a tak?

Mřížka s X a Y souřadnicemi

Asi nejpříhodnější řešení je uložit si o kolik políček se had má posunout, a to zvlášť v x-ovém a zvlášť v y-ovém směru. Čili jako dvojici:

  • (1, 0) = doprava (o jedno políčko v kladném x-ovém směru; v y-ovém neposouvat)
  • (-1, 0) = doleva (o jedno políčko v záporném x-ovém směru)
  • (0, 1) = nahoru (+y)
  • (0, -1) = dolů (-y)

Nový atribut přidej do metody __init__ ve stavu:

        self.snake_direction = 0, 1

A v metodě move změň nastavování new_x a new_y podle nového atributu:

        dir_x, dir_y = self.snake_direction
        new_x = old_x + dir_x
        new_y = old_y + dir_y

Směr hada teď můžeš měnit změnou snake_direction v __init__. Funguje to? (Jestli ne, oprav to – a jestli to nejde, zavolej někoho na pomoc!)

Nyní zbývá atribut snake_direction měnit, když uživatel něco stiskne na klávesnici. To už je doména Pygletu.

Je potřeba přidat funkci, která reaguje na stisk klávesy. Aby Pyglet tuhle funkci našel a uměl zavolat, musí se jmenovat on_key_press, musí mít dekorátor @window.event, a musí brát dva parametry: číslo klávesy, která byla zmáčknutá a informace o modifikátorech jako Shift nebo Ctrl:

@window.event
def on_key_press(key_code, modifier):
    ...

Druhý parametr nebude v naší hře potřeba, ale v hlavičce funkce musí být.

Podle prvního ale nastav aktuální směr hada. Čísla kláves jsou definována v modulu pyglet.window.key jako konstanty se jmény LEFT, ENTER, Q či AMPERSAND . My použijeme šipky – LEFT, RIGHT, UP a DOWN:

@window.event
def on_key_press(key_code, modifier):
    if key_code == pyglet.window.key.LEFT:
        state.snake_direction = -1, 0
    if key_code == pyglet.window.key.RIGHT:
        state.snake_direction = 1, 0
    if key_code == pyglet.window.key.DOWN:
        state.snake_direction = 0, -1
    if key_code == pyglet.window.key.UP:
        state.snake_direction = 0, 1

Tuhle funkci je potřeba dát někam za nastavení window (aby byl k dispozici window.event) a před pyglet.app.run() (protože nastavovat ovládání až potom, co hra proběhne, je zbytečné). Nejlepší je ji dát vedle jiné funkce s dekorátorem @window.event, aby byly pěkně pohromadě.

Funguje to? Můžeš ovládat směr hada? To je skvělé! Určitě ale při zkoušení narazíš na pár věcí, které je potřeba dodělat:

  • Had by neměl mít možnost vylézt ven z okýnka.
  • Had by měl jíst jídlo a růst.
  • Hra by měla skončit, když had narazí sám do sebe nebo do okraje okna.

Pojďme je vyřešit, jednu po druhé.

Zatím dobrý, teď ale narazíme

„Hadí“ hry jako ta naše mají dvě varianty: buď je kolem hřiště „zeď“ a hráč při nárazu do okraje prohraje, nebo je hřiště „nekonečné“ – had okrajem proleze a objeví se na druhé straně. My naprogramujeme tu první variantu – zeď.

Abys zjistila, jestli had „vylezl“ z levého okraje okna ven, je potřeba zkontrolovat, jestli x-ová souřadnice hlavy je menší než 0. To je dobré udělat hned poté, co nové souřadnice hlavy získáš – konkrétně hned za řádkem new_head = new_x, new_y v metodě move.

A co při takovém nárazu udělat? Pro začátek bude nejjednodušší ukončit hru. Na to má Python funkci exit(), která funguje podobně jako když v programu nastane chyba. Jen místo chybového výpisu ukáže daný text.

Ukončení programu není příliš příjemný způsob, jak říct hráčovi že prohrál. Za chvíli ale tuhle část předěláme, tak prozatím tenhle jednoduchý způsob postačí.

    def move(self):
        old_x, old_y = self.snake[-1]
        dir_x, dir_y = self.snake_direction
        new_x = old_x + dir_x
        new_y = old_y + dir_y
        new_head = new_x, new_y

        # Nový kód – kontrola vylezení z hrací plochy
        if new_x < 0:
            exit('GAME OVER')

        self.snake.append(new_head)
        del self.snake[0]

Věřím, že zvládneš udělat stejnou kontrolu pro vylezení ze spodního okraje.

Jak ale ošetřit ty zbylé okraje – pravý a horní? Na to je potřeba znát velikost okýnka. A tu zná Pyglet; třída se stavem by k okýnku neměla mít přístup!

Na velikosti herní plochy závisí chování hry. Tahle informace tedy bude tedy muset být součást stavu. Pro začátek nějakou velikost – třeba 10×10 – nastav v __init__:

        self.width = 10
        self.height = 10

A pak zařiď, aby po nárazu na neviditelnou stěnu kolem hřiště velkého 10×10 políček hra skončila. Pořádně vyzkoušej všechny varianty – severní, jižní, východní i západní zeď. Had je virtuální, nemusíš se bát že mu z toho vyroste boule.

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A pak v souboru se hrou hned po tom co vytvoříš stav (state = State()) a okýnko (window) nastav opravdovou velikost. Použij celočíselné dělení, aby počet políček byl v celých číslech:

state.width = window.width // TILE_SIZE
state.height = window.height // TILE_SIZE

Krmení

Tak. Had je v kleci, už nemůže vylézt. Co dál?

Teď se musíš o hada postarat: pravidelně ho krmit. Ale ještě předtím je potřeba ho naučit, jak se vůbec jí – na naši potravu ještě není zvyklý. Když to zvládneš, poroste jako z vody!

Konkrétně musíš hlavně zajistit aby, když se had připlazí na políčko s jídlem, jídlo zmizelo. K tomu se dá použít:

  • operátor in, který zjišťuje jestli něco (třeba souřadnice) je v nějakém seznamu (třeba seznamu souřadnic jídla), a
  • metoda remove, která ze seznamu odstraní daný prvek (podle hodnoty prvku – na rozdíl od del, který maže podle pozice).

Za kontrolu vylezení z hrací plochy potřebuješ dát kód, který dělá následující:

  • Pokud je nová pozice hlavy v seznamu souřadnic jídla:
    • Odeber tuhle pozici ze seznamu souřadnic jídla

Zvládneš ho napsat?

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Vyzkoušej, jestli to funguje. Had by měl jíst jídlo.

Ještě ale zbývá zařídit, aby po každém soustu trochu povyrostl. Ale jak? Kterým směrem má růst?

Tady je dobré se podívat na existující kód a uvědomit si, co dělá.

Náš had se plazí tak, že napřed vepředu povyroste (pomocí append) a potom se vzadu zmenší (pomocí del self.snake[0]).

Aby tedy po snězení jídla vyrostl, stačí přeskočit ono zmenšování! Ono přeskočit znamená podmínit, pomocí if. Logika jezení a zmenšování hada tedy bude:

  • Když had sní jídlo, jídlo zmizí. Had se nezmenší.
  • Jinak (tedy když had nesní jídlo) se had zmenší (a tudíž neroste).

Neboli přeloženo do Pythonu:

        if new_head in self.food:
            self.food.remove(new_head)
        else:
            del self.snake[0]

Pro ty, co se začínají ztrácet, dám k dispozici celou metodu move. Běda ale těm, kdo opisují kód aniž by se mu snažili porozumět!

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Nové jídlo

Když už had umí jíst, je potřeba mu zajistit pravidelný přísun jídla. Nejlépe tak, že se každé snězené jídlo nahradí novým.

Přidej do třídy State následující novou metodu, která umí přidat jídlo:

    def add_food(self):
        x = 0
        y = 0
        position = x, y
        self.food.append(position)

Pak tuhle metodu zavolej – najdi v programu kód, který se provádí když je potřeba přidat nové jídlo, a přidej tam následující řádek:

            self.add_food()

Tahle metoda přidává jídlo na pozici (0, 0), tedy stále do stejného rohu. Bylo by ale fajn, kdyby se nové jídlo objevilo vždycky jinde, na náhodném místě. Na to můžeme použít funkci random.randrange. Vzpomeň si, že volání randrage(N) vrátí náhodné celé číslo od 0 do N - 1.

Jaký rozsah čísel potřebujeme pro hadí jídlo?

Až na to přijdeš, zkus přidat náhodu do programu: jídlo by se mělo objevit na úplně náhjodném políčku na herní ploše.

Nezapomeň na import random – to patří na úplný začátek souboru. Další změny ale už dělej jen v metodě add_food.

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Až to budeš testovat, asi zjistíš, že úplně náhodné políčko není ideální. Občas se totiž jídlo objeví na políčku s hadem, nebo dokonce na jiném jídle. Je proto dobré tuhle situaci zkontrolovat, a když volba padne na plné políčko, jídlo nepřidávat:

        if (position not in self.snake) and (position not in self.food):
            self.food.append(position)

Když ale zkusíš tohle, zjistíš, že občas se nové jídlo vůbec nepřidá. To taky není vhodná varianta – had by tak měl hlad. Co s tím?

Překvapivě dobré (i když ne úplně ideální) řešení je zkusit políčko vybrat několikrát. Když padne prázdné políčko, šup tam s jídlem; když padne plné, tak to prostě zkusit znovu.

Je ale potřeba počet pokusů omezit, aby v situaci, kdy je pole úplně plné, počítač nevybíral donekonečna. Řekněme že když se na 100 pokusů nepodaří prázdné políčko vybrat, vzdáme to. Jídla už je nejspíš dost.

Metoda add_food po všech úpravách bude vypadat takhle:

    def add_food(self):
        for try_number in range(100):
            x = random.randrange(self.width)
            y = random.randrange(self.height)
            position = x, y
            if (position not in self.snake) and (position not in self.food):
                self.food.append(position)
                # Ukončení funkce ("vyskočí" i z cyklu for)
                return

Jestli ti to funguje, ještě zařiď, aby na začátku hry bylo jídlo na náhodných pozicích.

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Konec

Had teď může narůst do obrovských rozměrů – a lze prohrát jen tím, že narazí do stěny. Zaříď teď, aby hra skončila i když narazí sám do sebe.

Jak na to? Do metody move, vedle kontrola vylezení z hrací plochy, dej kód který udělá následující:

  • Pokud jsou souřadnice nové hlavy už součást hada:
    • Ukonči hru (podobně jako po nárazu do stěny).

Dokážeš to převést do Pythonu?

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Hotovo!

Pauza

Není ale dobré při konci hry ukončit celý program a zavřít okýnko.

Lepší je hru „zapauzovat“ a ukázat hráči situaci, do které nešťastného hada dostal, aby se z ní mohl pro příště poučit.

Aby to bylo možné, dáme do stavu hry další atribut: alive. Ten bude nastavený na True, dokud bude had žít. Když had narazí, nastaví se na False, a od té doby se už nebude pohybovat. Je dobré i graficky ukázat, že hadovi není dobře – hráč pak spíš bude zpytovat svědomí.

Zkus zapřemýšlet, kam v kódu patří následující kousky kódu, které prohru implementují:

        # Prvotní nastavení atributu
        self.alive = True

        # Zastavení hada
        self.alive = False

        # Zabránění pohybu
        if not self.alive:
            return

        # Grafická indikace
        if after == 'end' and not state.alive:
            after = 'dead'

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A to je vše?

Gratuluji, máš funkční a hratelnou hru! Doufám že jsi na sebe hrdá!

Dej si něco sladkého, zasloužíš si to.

Tady je moje řešení. To se touhle dobou od toho tvého může dost lišit – to je úplně normální. (A nedívej se sem dokud hada nenaprogramuješ sama, Chybami a neustálým zkoušením se člověk učí – a programátor zvlášť. Čtením už vyřešeného se učí hůř.)

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Co dál?

Najdeš ještě nějaké další vylepšení, které by se dalo udělat?

Zkus třeba následující rozšíření. Jsou seřazené zhruba podle složitosti:

  • Vylepši ovládání (a hratelnost!) podle návodu.

  • Každých 30 vteřin hry přibude samo od sebe nové jídlo, takže jich pak bude na hrací ploše víc.

  • Hra se bude postupně zrychlovat.
    (Na to je nejlepší předělat funkci move, aby sama naplánovala, kdy se má příště zavolat. Volání schedule_interval tak už nebude potřeba.)

  • Když had vyleze ven z okýnka, místo konce hry se objeví na druhé straně. (Viz návod.)

  • Hadi budou dva; druhý se ovládá klávesami W A S D.
    (Na to je nejlepší udělat novou třídu, Snake, a všechen stav hada přesunout ze State do ní. Ve State pak měj seznam hadů. Téhle změně je potřeba přizpůsobit celý zytek programu.)

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  "data": {
    "sessionMaterial": {
      "id": "session-material:2019/brno-podzim-snake:workshop:3",
      "title": "Logika hry Had",
      "html": "\n          \n    \n\n    <h1>Logika hry</h1>\n<p>U&#x17E; um&#xED;&#x161; vykreslit hada ze seznamu sou&#x159;adnic.\nHad&#xED; videohra ale nebude jen &#x201E;fotka&#x201C;.\nSeznam se bude m&#x11B;nit a had se bude h&#xFD;bat!</p>\n<!--\n# Ukládání revizí\n\nXXX - Nestíhám dopsat, omlouvám se\n-->\n\n<h1>Rozh&#xFD;bejme hada</h1>\n<p>Tv&#x16F;j program te&#x10F;, douf&#xE1;m, vypad&#xE1; n&#x11B;jak takhle:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"kn\">import</span> <span class=\"nn\">pyglet</span>\n\n<span class=\"n\">TILE_SIZE</span> <span class=\"o\">=</span> <span class=\"mi\">64</span>\n\n<span class=\"n\">snake</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">2</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">2</span><span class=\"p\">,</span> <span class=\"mi\">2</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">3</span><span class=\"p\">,</span> <span class=\"mi\">2</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">3</span><span class=\"p\">,</span> <span class=\"mi\">3</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">3</span><span class=\"p\">,</span> <span class=\"mi\">4</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">3</span><span class=\"p\">,</span> <span class=\"mi\">5</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">4</span><span class=\"p\">,</span> <span class=\"mi\">5</span><span class=\"p\">)]</span>\n<span class=\"n\">food</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">2</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">5</span><span class=\"p\">,</span> <span class=\"mi\">1</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">4</span><span class=\"p\">)]</span>\n\n<span class=\"n\">red_image</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">image</span><span class=\"o\">.</span><span class=\"n\">load</span><span class=\"p\">(</span><span class=\"s1\">&apos;apple.png&apos;</span><span class=\"p\">)</span>\n<span class=\"n\">snake_tiles</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n<span class=\"k\">for</span> <span class=\"n\">start</span> <span class=\"ow\">in</span> <span class=\"p\">[</span><span class=\"s1\">&apos;bottom&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;end&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;left&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;right&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;top&apos;</span><span class=\"p\">]:</span>\n    <span class=\"k\">for</span> <span class=\"n\">end</span> <span class=\"ow\">in</span> <span class=\"p\">[</span><span class=\"s1\">&apos;bottom&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;end&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;left&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;right&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;top&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;dead&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;tongue&apos;</span><span class=\"p\">]:</span>\n        <span class=\"n\">key</span> <span class=\"o\">=</span> <span class=\"n\">start</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;-&apos;</span> <span class=\"o\">+</span> <span class=\"n\">end</span>\n        <span class=\"n\">image</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">image</span><span class=\"o\">.</span><span class=\"n\">load</span><span class=\"p\">(</span><span class=\"s1\">&apos;snake-tiles/&apos;</span> <span class=\"o\">+</span> <span class=\"n\">key</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;.png&apos;</span><span class=\"p\">)</span>\n        <span class=\"n\">snake_tiles</span><span class=\"p\">[</span><span class=\"n\">key</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"n\">image</span>\n\n<span class=\"n\">window</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">Window</span><span class=\"p\">()</span>\n\n<span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_draw</span><span class=\"p\">():</span>\n    <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">clear</span><span class=\"p\">()</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glEnable</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_BLEND</span><span class=\"p\">)</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glBlendFunc</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_SRC_ALPHA</span><span class=\"p\">,</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_ONE_MINUS_SRC_ALPHA</span><span class=\"p\">)</span>\n    <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">snake</span><span class=\"p\">:</span>\n        <span class=\"n\">before</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;end&apos;</span>     <span class=\"c1\"># (Tady p&#x159;&#xED;padn&#x11B; je n&#x11B;jak&#xE9;</span>\n        <span class=\"n\">after</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;end&apos;</span>      <span class=\"c1\">#  slo&#x17E;it&#x11B;j&#x161;&#xED; vyb&#xED;r&#xE1;n&#xED; pol&#xED;&#x10D;ka)</span>\n        <span class=\"n\">snake_tiles</span><span class=\"p\">[</span><span class=\"n\">before</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;-&apos;</span> <span class=\"o\">+</span> <span class=\"n\">after</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">blit</span><span class=\"p\">(</span>\n            <span class=\"n\">x</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">width</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">height</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">)</span>\n    <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">food</span><span class=\"p\">:</span>\n        <span class=\"n\">red_image</span><span class=\"o\">.</span><span class=\"n\">blit</span><span class=\"p\">(</span>\n            <span class=\"n\">x</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">width</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">height</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">)</span>\n\n<span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">app</span><span class=\"o\">.</span><span class=\"n\">run</span><span class=\"p\">()</span>\n</pre></div><p>Zkus t&#x11B;sn&#x11B; nad &#x159;&#xE1;dek <code>pyglet.app.run</code> doplnit funkci,\nkter&#xE1; se bude volat ka&#x17E;dou &#x161;estinu vte&#x159;iny\na p&#x159;id&#xE1; hadovi pol&#xED;&#x10D;ko nav&#xED;c:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"n\">dt</span><span class=\"p\">):</span>\n    <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">=</span> <span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n    <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">x</span> <span class=\"o\">+</span> <span class=\"mi\">1</span>\n    <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">y</span>\n    <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n    <span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n\n<span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">clock</span><span class=\"o\">.</span><span class=\"n\">schedule_interval</span><span class=\"p\">(</span><span class=\"n\">move</span><span class=\"p\">,</span> <span class=\"mi\">1</span><span class=\"o\">/</span><span class=\"mi\">6</span><span class=\"p\">)</span>\n</pre></div><p>Funguje?\nTak do t&#xE9;hle funkce je&#x161;t&#x11B; p&#x159;idej <code>del snake[0]</code>, aby had nerostl donekone&#x10D;na.\nV&#xED;&#x161; co tenhle p&#x159;&#xED;kaz d&#x11B;l&#xE1;? Jestli ne, koukni znovu na pozn&#xE1;mky k&#xA0;seznam&#x16F;m!</p>\n<p>Zvl&#xE1;dne&#x161; funkci upravit tak, aby had lezl nahoru?</p>\n<p>Jestli ano, gratuluji!\nZv&#xFD;v&#xE1; sm&#x11B;r hada ovl&#xE1;dat &#x161;ipkami na kl&#xE1;vesnici, a v&#x11B;t&#x161;ina hry bude hotov&#xE1;!</p>\n<h2>T&#x159;&#xED;da pro stav</h2>\n<p>Ne&#x17E; ale ud&#x11B;l&#xE1;me interaktivn&#xED;ho hada, zkus&#xED;me tro&#x161;ku uklidit.\nProgram se n&#xE1;m rozr&#x16F;st&#xE1; a za chv&#xED;li bude slo&#x17E;it&#xE9; se v&#xA0;n&#x11B;m vyznat.</p>\n<p>Stav hry m&#xE1;me zat&#xED;m ve dvou seznamech: <code>snake</code> a <code>food</code>.\n&#x10C;asem ale bude podobn&#xFD;ch prom&#x11B;nn&#xFD;ch v&#xED;c.</p>\n<p>Abychom je m&#x11B;li v&#x161;echny pohromad&#x11B;, vytvo&#x159;&#xED;me pro stav hry <em>t&#x159;&#xED;du</em>.</p>\n<p>Na v&#x161;echno, co se ve h&#x159;e m&#x16F;&#x17E;e st&#xE1;t, nadefinujeme <em>metody</em>.\nZat&#xED;m budou dv&#x11B;: za&#x10D;&#xE1;tek hry a pohyb hada.</p>\n<p>Na za&#x10D;&#xE1;tku hry se zavol&#xE1; metoda <code>__init__</code>.\nM&#xE1; trochu divn&#xE9; jm&#xE9;no se dv&#x11B;ma podtr&#x17E;&#xED;tkama na ka&#x17E;d&#xE9; stran&#x11B;.\nPodle toho Python v&#xED;, &#x17E;e tahle metoda je speci&#xE1;ln&#xED; a se m&#xE1; volat\np&#x159;i vytvo&#x159;en&#xED; objektu.</p>\n<p>Metoda <code>__init__</code> nastav&#xED; cel&#xFD; stav hry jako <em>atributy</em>.\nStav hry je v&#x161;echno, co pot&#x159;ebujeme o h&#x159;e v&#x11B;d&#x11B;t a m&#x16F;&#x17E;e se to &#x10D;asem m&#x11B;nit.\nV&#xA0;na&#x161;em p&#x159;&#xED;pad&#x11B; to zat&#xED;m budou sou&#x159;adnice hada a j&#xED;dla.</p>\n<p>Metoda <code>move</code>, kterou budeme volat p&#x159;i ka&#x17E;d&#xE9;m &#x201E;tahu&#x201C; hry, je bude tyhle\natributy m&#x11B;nit.</p>\n<p>Pro funk&#x10D;nost, kterou zat&#xED;m n&#xE1;&#x161; had um&#xED;, bude t&#x159;&#xED;da se stavem vypadat\nn&#xE1;sledovn&#x11B;.\nP&#x159;idej ji do programu hned za nastaven&#xED; konstant.</p>\n<div class=\"highlight\"><pre><span></span><span class=\"k\">class</span> <span class=\"nc\">State</span><span class=\"p\">:</span>\n    <span class=\"k\">def</span> <span class=\"fm\">__init__</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">2</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">5</span><span class=\"p\">,</span> <span class=\"mi\">1</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">4</span><span class=\"p\">)]</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">)]</span>\n\n    <span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">old_x</span><span class=\"p\">,</span> <span class=\"n\">old_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"mi\">1</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span>\n        <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n</pre></div><div class=\"admonition note\"><p>Pou&#x17E;ij pros&#xED;m pro t&#x159;&#xED;du jm&#xE9;no <code>State</code> a i atributy pojmenuj podle\nmateri&#xE1;l&#x16F; (<code>snake</code>, <code>food</code>, a pozd&#x11B;ji i dal&#x161;&#xED;).\nBude se ti to hodit.</p>\n</div><p>V&#x161;imni si, &#x17E;e metody berou argument <code>self</code>.\nTo ozna&#x10D;uje konkr&#xE9;tn&#xED; objekt, stav hry se kter&#xFD;m metoda pracuje nebo\nkter&#xFD; m&#x11B;n&#xED;.\nKe v&#x161;em atribut&#x16F;m p&#x159;istupuj&#xED; pomoc&#xED; te&#x10D;ky &#x2013;\n<code>self.<var>jm&#xE9;no_atributu</var></code>.</p>\n<p>Tak, m&#xE1;me t&#x159;&#xED;du se stavem.\nNo jo, ale jak ji te&#x10F; pou&#x17E;&#xED;t?</p>\n<p>Na to pot&#x159;ebuje&#x161; je&#x161;t&#x11B; n&#x11B;kolik zm&#x11B;n:</p>\n<ul>\n<li><p>Nastavov&#xE1;n&#xED; seznam&#x16F; <code>snake</code> a <code>food</code> (mimo t&#x159;&#xED;du) zru&#x161;; m&#xED;sto nich nastav\njedinou prom&#x11B;nnou <code>state</code> na nov&#xFD; stav:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"n\">state</span> <span class=\"o\">=</span> <span class=\"n\">State</span><span class=\"p\">()</span>\n</pre></div></li>\n<li><p>M&#xED;sto <code>snake</code> a <code>food</code> ve funkci <code>on_draw</code> pou&#x17E;ij <code>state.snake</code>\na <code>state.food</code> &#x2013; atributy na&#x161;eho stavu.</p>\n<p>V&#x161;imni si &#x17E;e tady se nepou&#x17E;&#xED;v&#xE1; <code>self</code>, co&#x17E; je jm&#xE9;no kter&#xE9; pou&#x17E;&#xED;vaj&#xED; jen\n<em>metody</em> v&#xA0;r&#xE1;mci t&#x159;&#xED;dy.\nJinde mus&#xED;&#x161; pojmenovat konkr&#xE9;tn&#xED; objekt, se kter&#xFD;m pracujeme.</p>\n</li>\n<li><p>Funkci <code>move</code> p&#x159;epi&#x161; tak, aby jen volala metodu <code>state.move</code>:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"n\">dt</span><span class=\"p\">):</span>\n    <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">move</span><span class=\"p\">()</span>\n</pre></div><p>V&#x161;imni si &#x17E;e ani tady se nepou&#x17E;&#xED;v&#xE1; <code>self</code>.</p>\n</li>\n<li><p>Vykreslov&#xE1;n&#xED; hada z&#xA0;funkce <code>on_draw</code> p&#x159;esu&#x148; do nov&#xE9; metody\n<code>draw</code>:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"k\">class</span> <span class=\"nc\">State</span><span class=\"p\">:</span>\n  <span class=\"o\">...</span>\n\n  <span class=\"k\">def</span> <span class=\"nf\">draw</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n      <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">:</span>\n          <span class=\"o\">...</span>\n      <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n          <span class=\"o\">...</span>\n<span class=\"o\">...</span>\n\n<span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_draw</span><span class=\"p\">():</span>\n    <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">clear</span><span class=\"p\">()</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glEnable</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_BLEND</span><span class=\"p\">)</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glBlendFunc</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_SRC_ALPHA</span><span class=\"p\">,</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_ONE_MINUS_SRC_ALPHA</span><span class=\"p\">)</span>\n    <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">draw</span><span class=\"p\">()</span>\n</pre></div><p>V&#x161;imni si &#x17E;e ani tady se nepou&#x17E;&#xED;v&#xE1; <code>self</code>.</p>\n</li>\n</ul>\n<p>Povedlo se? Funguje to jako p&#x159;edt&#xED;m?\nPro kontrolu m&#x16F;&#x17E;e&#x161; sv&#x16F;j program porovnat s&#xA0;m&#xFD;m (ale nejde o jedin&#xE9; spr&#xE1;vn&#xE9;\n&#x159;e&#x161;en&#xED;):</p>\n<div class=\"solution\" id=\"solution-0\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/0/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span><span class=\"kn\">import</span> <span class=\"nn\">pyglet</span>\n\n<span class=\"n\">TILE_SIZE</span> <span class=\"o\">=</span> <span class=\"mi\">64</span>\n\n<span class=\"k\">class</span> <span class=\"nc\">State</span><span class=\"p\">:</span>\n    <span class=\"k\">def</span> <span class=\"fm\">__init__</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">2</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">5</span><span class=\"p\">,</span> <span class=\"mi\">1</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">4</span><span class=\"p\">)]</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">)]</span>\n\n    <span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">old_x</span><span class=\"p\">,</span> <span class=\"n\">old_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"mi\">1</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span>\n        <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n\n    <span class=\"k\">def</span> <span class=\"nf\">draw</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">:</span>\n            <span class=\"n\">before</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;end&apos;</span>     <span class=\"c1\"># (Tady p&#x159;&#xED;padn&#x11B; je n&#x11B;jak&#xE9;</span>\n            <span class=\"n\">after</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;end&apos;</span>      <span class=\"c1\">#  slo&#x17E;it&#x11B;j&#x161;&#xED; vyb&#xED;r&#xE1;n&#xED; pol&#xED;&#x10D;ka)</span>\n            <span class=\"n\">snake_tiles</span><span class=\"p\">[</span><span class=\"n\">before</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;-&apos;</span> <span class=\"o\">+</span> <span class=\"n\">after</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">blit</span><span class=\"p\">(</span>\n                <span class=\"n\">x</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">width</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">height</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">)</span>\n        <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n            <span class=\"n\">red_image</span><span class=\"o\">.</span><span class=\"n\">blit</span><span class=\"p\">(</span>\n                <span class=\"n\">x</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">width</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">height</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">)</span>\n\n<span class=\"n\">red_image</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">image</span><span class=\"o\">.</span><span class=\"n\">load</span><span class=\"p\">(</span><span class=\"s1\">&apos;apple.png&apos;</span><span class=\"p\">)</span>\n<span class=\"n\">snake_tiles</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n<span class=\"k\">for</span> <span class=\"n\">start</span> <span class=\"ow\">in</span> <span class=\"p\">[</span><span class=\"s1\">&apos;bottom&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;end&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;left&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;right&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;top&apos;</span><span class=\"p\">]:</span>\n    <span class=\"k\">for</span> <span class=\"n\">end</span> <span class=\"ow\">in</span> <span class=\"p\">[</span><span class=\"s1\">&apos;bottom&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;end&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;left&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;right&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;top&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;dead&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;tongue&apos;</span><span class=\"p\">]:</span>\n        <span class=\"n\">key</span> <span class=\"o\">=</span> <span class=\"n\">start</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;-&apos;</span> <span class=\"o\">+</span> <span class=\"n\">end</span>\n        <span class=\"n\">image</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">image</span><span class=\"o\">.</span><span class=\"n\">load</span><span class=\"p\">(</span><span class=\"s1\">&apos;snake-tiles/&apos;</span> <span class=\"o\">+</span> <span class=\"n\">key</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;.png&apos;</span><span class=\"p\">)</span>\n        <span class=\"n\">snake_tiles</span><span class=\"p\">[</span><span class=\"n\">key</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"n\">image</span>\n\n<span class=\"n\">window</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">Window</span><span class=\"p\">()</span>\n\n<span class=\"n\">state</span> <span class=\"o\">=</span> <span class=\"n\">State</span><span class=\"p\">()</span>\n\n<span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_draw</span><span class=\"p\">():</span>\n    <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">clear</span><span class=\"p\">()</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glEnable</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_BLEND</span><span class=\"p\">)</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glBlendFunc</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_SRC_ALPHA</span><span class=\"p\">,</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_ONE_MINUS_SRC_ALPHA</span><span class=\"p\">)</span>\n    <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">draw</span><span class=\"p\">()</span>\n\n<span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"n\">dt</span><span class=\"p\">):</span>\n    <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">move</span><span class=\"p\">()</span>\n\n<span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">clock</span><span class=\"o\">.</span><span class=\"n\">schedule_interval</span><span class=\"p\">(</span><span class=\"n\">move</span><span class=\"p\">,</span> <span class=\"mi\">1</span><span class=\"o\">/</span><span class=\"mi\">6</span><span class=\"p\">)</span>\n\n<span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">app</span><span class=\"o\">.</span><span class=\"n\">run</span><span class=\"p\">()</span>\n</pre></div>\n    </div>\n</div><h2>Ovl&#xE1;d&#xE1;n&#xED;</h2>\n<p>Nyn&#xED; k&#xA0;onomu sl&#xED;ben&#xE9;mu ovl&#xE1;d&#xE1;n&#xED;. Respektive nejd&#x159;&#xED;v k&#xA0;zm&#x11B;n&#xE1;m sm&#x11B;ru.</p>\n<p>Had ze hry se plaz&#xED; st&#xE1;le stejn&#xFD;m sm&#x11B;rem, dokud hr&#xE1;&#x10D; nezm&#xE1;ckne kl&#xE1;vesu.\nHad z na&#x161;&#xED; uk&#xE1;zky se plaz&#xED; doprava.\nJestli jsi to je&#x161;t&#x11B; neud&#x11B;lala, zkus za&#x159;&#xED;dit, aby se m&#xED;sto toho\nplazil nahoru.</p>\n<div class=\"solution\" id=\"solution-1\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/1/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <p>Ve funkci <code>move</code> je pot&#x159;eba jinak nastavit prom&#x11B;nn&#xE9; <code>new_x</code> a <code>new_y</code>:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">+</span> <span class=\"mi\">1</span>\n</pre></div>\n    </div>\n</div><p>A co dol&#x16F;?</p>\n<div class=\"solution\" id=\"solution-2\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/2/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span>        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">-</span> <span class=\"mi\">1</span>\n</pre></div>\n    </div>\n</div><p>Aby si had &#x201E;pamatoval&#x201C; kam se zrovna plaz&#xED;, je pot&#x159;eba m&#xED;t sm&#x11B;r jako sou&#x10D;&#xE1;st\nstavu hry.\nUlo&#x17E;me ho tedy do atrubutu jm&#xE9;nem <code>snake_direction</code>.</p>\n<p>Co tam ale p&#x159;esn&#x11B; ulo&#x17E;it?\nJak reprezentovat sm&#x11B;r v&#xA0;Pythonu &#x2013; pomoc&#xED; &#x10D;&#xED;sel, <var>n</var>-tic a tak?</p>\n<p><span class=\"figure\"><a href=\"/2019/brno-podzim-snake/snake/logic/static/coord-vectors.svg\"><img src=\"/2019/brno-podzim-snake/snake/logic/static/coord-vectors.svg\" alt=\"M&#x159;&#xED;&#x17E;ka s X a Y sou&#x159;adnicemi\"></a></span></p>\n<p>Asi nejp&#x159;&#xED;hodn&#x11B;j&#x161;&#xED; &#x159;e&#x161;en&#xED; je ulo&#x17E;it si o kolik pol&#xED;&#x10D;ek se had m&#xE1; posunout,\na to zvl&#xE1;&#x161;&#x165; v <var>x</var>-ov&#xE9;m a zvl&#xE1;&#x161;&#x165; v <var>y</var>-ov&#xE9;m sm&#x11B;ru.\n&#x10C;ili jako dvojici:</p>\n<ul>\n<li><code>(1, 0)</code> = doprava (o jedno pol&#xED;&#x10D;ko v&#xA0;kladn&#xE9;m <var>x</var>-ov&#xE9;m sm&#x11B;ru;\n v&#xA0;<var>y</var>-ov&#xE9;m neposouvat)</li>\n<li><code>(-1, 0)</code> = doleva (o jedno pol&#xED;&#x10D;ko v&#xA0;z&#xE1;porn&#xE9;m <var>x</var>-ov&#xE9;m sm&#x11B;ru)</li>\n<li><code>(0, 1)</code> = nahoru (+<var>y</var>)</li>\n<li><code>(0, -1)</code> = dol&#x16F; (-<var>y</var>)</li>\n</ul>\n<p>Nov&#xFD; atribut p&#x159;idej do metody <code>__init__</code> ve stavu:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">1</span>\n</pre></div><p>A v metod&#x11B; <code>move</code> zm&#x11B;&#x148; nastavov&#xE1;n&#xED; <code>new_x</code> a <code>new_y</code> podle nov&#xE9;ho atributu:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"n\">dir_x</span><span class=\"p\">,</span> <span class=\"n\">dir_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"n\">dir_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">+</span> <span class=\"n\">dir_y</span>\n</pre></div><p>Sm&#x11B;r hada te&#x10F; m&#x16F;&#x17E;e&#x161; m&#x11B;nit zm&#x11B;nou <code>snake_direction</code> v&#xA0;<code>__init__</code>.\nFunguje to? (Jestli ne, oprav to &#x2013; a jestli to nejde, zavolej n&#x11B;koho na pomoc!)</p>\n<p>Nyn&#xED; zb&#xFD;v&#xE1; atribut <code>snake_direction</code> m&#x11B;nit, kdy&#x17E; u&#x17E;ivatel n&#x11B;co stiskne na\nkl&#xE1;vesnici.\nTo u&#x17E; je dom&#xE9;na Pygletu.</p>\n<p>Je pot&#x159;eba p&#x159;idat funkci, kter&#xE1; reaguje na stisk kl&#xE1;vesy.\nAby Pyglet tuhle funkci na&#x161;el a um&#x11B;l zavolat, mus&#xED; se jmenovat <code>on_key_press</code>,\nmus&#xED; m&#xED;t dekor&#xE1;tor <code>@window.event</code>, a mus&#xED; br&#xE1;t dva parametry:\n&#x10D;&#xED;slo kl&#xE1;vesy, kter&#xE1; byla zm&#xE1;&#x10D;knut&#xE1; a informace o modifik&#xE1;torech\njako <kbd>Shift</kbd> nebo <kbd>Ctrl</kbd>:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_key_press</span><span class=\"p\">(</span><span class=\"n\">key_code</span><span class=\"p\">,</span> <span class=\"n\">modifier</span><span class=\"p\">):</span>\n    <span class=\"o\">...</span>\n</pre></div><p>Druh&#xFD; parametr nebude v&#xA0;na&#x161;&#xED; h&#x159;e pot&#x159;eba, ale v&#xA0;hlavi&#x10D;ce funkce mus&#xED; b&#xFD;t.</p>\n<p>Podle prvn&#xED;ho ale nastav aktu&#xE1;ln&#xED; sm&#x11B;r hada.\n&#x10C;&#xED;sla kl&#xE1;ves jsou definov&#xE1;na v&#xA0;modulu <a href=\"https://pyglet.readthedocs.io/en/pyglet-1.3-maintenance/modules/window_key.html#key-constants\"><code>pyglet.window.key</code></a>\njako konstanty se jm&#xE9;ny <code>LEFT</code>, <code>ENTER</code>, <code>Q</code> &#x10D;i <code>AMPERSAND</code> .\nMy pou&#x17E;ijeme &#x161;ipky &#x2013; <code>LEFT</code>, <code>RIGHT</code>, <code>UP</code> a <code>DOWN</code>:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_key_press</span><span class=\"p\">(</span><span class=\"n\">key_code</span><span class=\"p\">,</span> <span class=\"n\">modifier</span><span class=\"p\">):</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">LEFT</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">RIGHT</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">DOWN</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"o\">-</span><span class=\"mi\">1</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">UP</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">1</span>\n</pre></div><p>Tuhle funkci je pot&#x159;eba d&#xE1;t n&#x11B;kam za nastaven&#xED; <code>window</code> (aby byl k&#xA0;dispozici\n<code>window.event</code>) a p&#x159;ed <code>pyglet.app.run()</code> (proto&#x17E;e nastavovat ovl&#xE1;d&#xE1;n&#xED; a&#x17E;\npotom, co hra prob&#x11B;hne, je zbyte&#x10D;n&#xE9;).\nNejlep&#x161;&#xED; je ji d&#xE1;t vedle jin&#xE9; funkce s&#xA0;dekor&#xE1;torem <code>@window.event</code>,\naby byly p&#x11B;kn&#x11B; pohromad&#x11B;.</p>\n<p>Funguje to?\nM&#x16F;&#x17E;e&#x161; ovl&#xE1;dat sm&#x11B;r hada?\nTo je skv&#x11B;l&#xE9;!\nUr&#x10D;it&#x11B; ale p&#x159;i zkou&#x161;en&#xED; naraz&#xED;&#x161; na p&#xE1;r v&#x11B;c&#xED;, kter&#xE9; je pot&#x159;eba dod&#x11B;lat:</p>\n<ul>\n<li>Had by nem&#x11B;l m&#xED;t mo&#x17E;nost vyl&#xE9;zt ven z&#xA0;ok&#xFD;nka.</li>\n<li>Had by m&#x11B;l j&#xED;st j&#xED;dlo a r&#x16F;st.</li>\n<li>Hra by m&#x11B;la skon&#x10D;it, kdy&#x17E; had naraz&#xED; s&#xE1;m do sebe nebo do okraje okna.</li>\n</ul>\n<p>Poj&#x10F;me je vy&#x159;e&#x161;it, jednu po druh&#xE9;.</p>\n<h2>Zat&#xED;m dobr&#xFD;, te&#x10F; ale naraz&#xED;me</h2>\n<p>&#x201E;Had&#xED;&#x201C; hry jako ta na&#x161;e maj&#xED; dv&#x11B; varianty: bu&#x10F; je kolem h&#x159;i&#x161;t&#x11B; &#x201E;ze&#x10F;&#x201C;\na hr&#xE1;&#x10D; p&#x159;i n&#xE1;razu do okraje prohraje, nebo je h&#x159;i&#x161;t&#x11B; &#x201E;nekone&#x10D;n&#xE9;&#x201C; &#x2013; had okrajem\nproleze a objev&#xED; se na druh&#xE9; stran&#x11B;.\nMy naprogramujeme tu prvn&#xED; variantu &#x2013; ze&#x10F;.</p>\n<p>Abys zjistila, jestli had &#x201E;vylezl&#x201C; z&#xA0;lev&#xE9;ho okraje okna ven,\nje pot&#x159;eba zkontrolovat, jestli <var>x</var>-ov&#xE1; sou&#x159;adnice hlavy\nje men&#x161;&#xED; ne&#x17E; 0.\nTo je dobr&#xE9; ud&#x11B;lat hned pot&#xE9;, co nov&#xE9; sou&#x159;adnice hlavy z&#xED;sk&#xE1;&#x161; &#x2013; konkr&#xE9;tn&#x11B;\nhned za &#x159;&#xE1;dkem <code>new_head = new_x, new_y</code> v&#xA0;metod&#x11B; <code>move</code>.</p>\n<p>A co p&#x159;i takov&#xE9;m n&#xE1;razu ud&#x11B;lat?\nPro za&#x10D;&#xE1;tek bude nejjednodu&#x161;&#x161;&#xED; ukon&#x10D;it hru.\nNa to m&#xE1; Python funkci <code>exit()</code>, kter&#xE1; funguje podobn&#x11B; jako kdy&#x17E; v&#xA0;programu\nnastane chyba.\nJen m&#xED;sto chybov&#xE9;ho v&#xFD;pisu uk&#xE1;&#x17E;e dan&#xFD; text.</p>\n<p>Ukon&#x10D;en&#xED; programu nen&#xED; p&#x159;&#xED;li&#x161; p&#x159;&#xED;jemn&#xFD; zp&#x16F;sob, jak &#x159;&#xED;ct hr&#xE1;&#x10D;ovi &#x17E;e prohr&#xE1;l.\nZa chv&#xED;li ale tuhle &#x10D;&#xE1;st p&#x159;ed&#x11B;l&#xE1;me, tak prozat&#xED;m tenhle jednoduch&#xFD; zp&#x16F;sob posta&#x10D;&#xED;.</p>\n<div class=\"highlight\"><pre><span></span>    <span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">old_x</span><span class=\"p\">,</span> <span class=\"n\">old_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n        <span class=\"n\">dir_x</span><span class=\"p\">,</span> <span class=\"n\">dir_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"n\">dir_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">+</span> <span class=\"n\">dir_y</span>\n        <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n\n        <span class=\"c1\"># Nov&#xFD; k&#xF3;d &#x2013; kontrola vylezen&#xED; z hrac&#xED; plochy</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n</pre></div><p>V&#x11B;&#x159;&#xED;m, &#x17E;e zvl&#xE1;dne&#x161; ud&#x11B;lat stejnou kontrolu pro vylezen&#xED; ze spodn&#xED;ho okraje.</p>\n<p>Jak ale o&#x161;et&#x159;it ty zbyl&#xE9; okraje &#x2013; prav&#xFD; a horn&#xED;?\nNa to je pot&#x159;eba zn&#xE1;t velikost ok&#xFD;nka.\nA tu zn&#xE1; Pyglet; t&#x159;&#xED;da se stavem by k&#xA0;ok&#xFD;nku nem&#x11B;la m&#xED;t p&#x159;&#xED;stup!</p>\n<p>Na velikosti hern&#xED; plochy z&#xE1;vis&#xED; chov&#xE1;n&#xED; hry.\nTahle informace tedy bude tedy muset b&#xFD;t sou&#x10D;&#xE1;st stavu.\nPro za&#x10D;&#xE1;tek n&#x11B;jakou velikost &#x2013; t&#x159;eba 10&#xD7;10 &#x2013; nastav v&#xA0;<code>__init__</code>:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span> <span class=\"o\">=</span> <span class=\"mi\">10</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span> <span class=\"o\">=</span> <span class=\"mi\">10</span>\n</pre></div><p>A pak za&#x159;i&#x10F;, aby po n&#xE1;razu na neviditelnou st&#x11B;nu kolem h&#x159;i&#x161;t&#x11B; velk&#xE9;ho\n10&#xD7;10 pol&#xED;&#x10D;ek hra skon&#x10D;ila.\nPo&#x159;&#xE1;dn&#x11B; vyzkou&#x161;ej v&#x161;echny varianty &#x2013; severn&#xED;, ji&#x17E;n&#xED;, v&#xFD;chodn&#xED; i z&#xE1;padn&#xED; ze&#x10F;.\nHad je virtu&#xE1;ln&#xED;, nemus&#xED;&#x161; se b&#xE1;t &#x17E;e mu z&#xA0;toho vyroste boule.</p>\n<div class=\"solution\" id=\"solution-3\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/3/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span>    <span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">old_x</span><span class=\"p\">,</span> <span class=\"n\">old_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n        <span class=\"n\">dir_x</span><span class=\"p\">,</span> <span class=\"n\">dir_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"n\">dir_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">+</span> <span class=\"n\">dir_y</span>\n\n        <span class=\"c1\"># Kontrola vylezen&#xED; z hrac&#xED; plochy</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_y</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&gt;=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_y</span> <span class=\"o\">&gt;=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n\n        <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n</pre></div>\n    </div>\n</div><p>A pak v&#xA0;souboru se hrou hned po tom co vytvo&#x159;&#xED;&#x161; stav (<code>state = State()</code>)\na ok&#xFD;nko (<code>window</code>) nastav <em>opravdovou</em> velikost.\nPou&#x17E;ij celo&#x10D;&#xED;seln&#xE9; d&#x11B;len&#xED;, aby po&#x10D;et pol&#xED;&#x10D;ek byl v&#xA0;cel&#xFD;ch &#x10D;&#xED;slech:</p>\n<div class=\"highlight\"><pre><span></span><span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">width</span> <span class=\"o\">=</span> <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">width</span> <span class=\"o\">//</span> <span class=\"n\">TILE_SIZE</span>\n<span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">height</span> <span class=\"o\">=</span> <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">height</span> <span class=\"o\">//</span> <span class=\"n\">TILE_SIZE</span>\n</pre></div><h2>Krmen&#xED;</h2>\n<p>Tak. Had je v&#xA0;kleci, u&#x17E; nem&#x16F;&#x17E;e vyl&#xE9;zt.\nCo d&#xE1;l?</p>\n<p>Te&#x10F; se mus&#xED;&#x161; o hada postarat: pravideln&#x11B; ho krmit.\nAle je&#x161;t&#x11B; p&#x159;edt&#xED;m je pot&#x159;eba ho nau&#x10D;it, jak se v&#x16F;bec j&#xED; &#x2013; na na&#x161;i potravu\nje&#x161;t&#x11B; nen&#xED; zvykl&#xFD;.\nKdy&#x17E; to zvl&#xE1;dne&#x161;, poroste jako z vody!</p>\n<p>Konkr&#xE9;tn&#x11B; mus&#xED;&#x161; hlavn&#x11B; zajistit aby, kdy&#x17E; se had p&#x159;iplaz&#xED; na pol&#xED;&#x10D;ko\ns&#xA0;j&#xED;dlem, j&#xED;dlo zmizelo.\nK tomu se d&#xE1; pou&#x17E;&#xED;t:</p>\n<ul>\n<li>oper&#xE1;tor <code>in</code>, kter&#xFD; zji&#x161;&#x165;uje jestli n&#x11B;co (t&#x159;eba\nsou&#x159;adnice) je v&#xA0;n&#x11B;jak&#xE9;m seznamu (t&#x159;eba seznamu sou&#x159;adnic j&#xED;dla), a</li>\n<li>metoda <code>remove</code>, kter&#xE1; ze seznamu odstran&#xED; dan&#xFD; prvek (podle <em>hodnoty</em> prvku\n&#x2013; na rozd&#xED;l od <code>del</code>, kter&#xFD; ma&#x17E;e podle pozice).</li>\n</ul>\n<p>Za kontrolu vylezen&#xED; z&#xA0;hrac&#xED; plochy pot&#x159;ebuje&#x161; d&#xE1;t k&#xF3;d,\nkter&#xFD; d&#x11B;l&#xE1; n&#xE1;sleduj&#xED;c&#xED;:</p>\n<ul>\n<li>Pokud je nov&#xE1; pozice hlavy v&#xA0;seznamu sou&#x159;adnic j&#xED;dla:<ul>\n<li>Odeber tuhle pozici ze seznamu sou&#x159;adnic j&#xED;dla</li>\n</ul>\n</li>\n</ul>\n<p>Zvl&#xE1;dne&#x161; ho napsat?</p>\n<div class=\"solution\" id=\"solution-4\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/4/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span>        <span class=\"k\">if</span> <span class=\"n\">new_head</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">remove</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n</pre></div>\n    </div>\n</div><p>Vyzkou&#x161;ej, jestli to funguje. Had by m&#x11B;l j&#xED;st j&#xED;dlo.</p>\n<p>Je&#x161;t&#x11B; ale zb&#xFD;v&#xE1; za&#x159;&#xED;dit, aby po ka&#x17E;d&#xE9;m soustu trochu povyrostl.\nAle jak? Kter&#xFD;m sm&#x11B;rem m&#xE1; r&#x16F;st?</p>\n<p>Tady je dobr&#xE9; se pod&#xED;vat na existuj&#xED;c&#xED; k&#xF3;d a uv&#x11B;domit si, co d&#x11B;l&#xE1;.</p>\n<p>N&#xE1;&#x161; had se plaz&#xED; tak, &#x17E;e nap&#x159;ed vep&#x159;edu povyroste (pomoc&#xED; <code>append</code>)\na potom se vzadu zmen&#x161;&#xED; (pomoc&#xED; <code>del self.snake[0]</code>).</p>\n<p>Aby tedy po sn&#x11B;zen&#xED; j&#xED;dla vyrostl, sta&#x10D;&#xED; <em>p&#x159;esko&#x10D;it</em> ono zmen&#x161;ov&#xE1;n&#xED;!\nOno <em>p&#x159;esko&#x10D;it</em> znamen&#xE1; podm&#xED;nit, pomoc&#xED; <code>if</code>.\nLogika jezen&#xED; a zmen&#x161;ov&#xE1;n&#xED; hada tedy bude:</p>\n<ul>\n<li>Kdy&#x17E; had sn&#xED; j&#xED;dlo, j&#xED;dlo zmiz&#xED;. Had se nezmen&#x161;&#xED;.</li>\n<li>Jinak (tedy kdy&#x17E; had <em>nesn&#xED;</em> j&#xED;dlo) se had zmen&#x161;&#xED; (a tud&#xED;&#x17E; neroste).</li>\n</ul>\n<p>Neboli p&#x159;elo&#x17E;eno do Pythonu:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"k\">if</span> <span class=\"n\">new_head</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">remove</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">else</span><span class=\"p\">:</span>\n            <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n</pre></div><p>Pro ty, co se za&#x10D;&#xED;naj&#xED; ztr&#xE1;cet, d&#xE1;m k dispozici celou metodu <code>move</code>.\nB&#x11B;da ale t&#x11B;m, kdo opisuj&#xED; k&#xF3;d ani&#x17E; by se mu sna&#x17E;ili porozum&#x11B;t!</p>\n<div class=\"solution\" id=\"solution-5\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/5/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span>    <span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">old_x</span><span class=\"p\">,</span> <span class=\"n\">old_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n        <span class=\"n\">dir_x</span><span class=\"p\">,</span> <span class=\"n\">dir_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"n\">dir_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">+</span> <span class=\"n\">dir_y</span>\n        <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n\n        <span class=\"c1\"># Kontrola vylezen&#xED; z hrac&#xED; plochy</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_y</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&gt;=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_y</span> <span class=\"o\">&gt;=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_head</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">remove</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n        <span class=\"k\">else</span><span class=\"p\">:</span>\n            <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n</pre></div>\n    </div>\n</div><h3>Nov&#xE9; j&#xED;dlo</h3>\n<p>Kdy&#x17E; u&#x17E; had um&#xED; j&#xED;st, je pot&#x159;eba mu zajistit pravideln&#xFD; p&#x159;&#xED;sun j&#xED;dla.\nNejl&#xE9;pe tak, &#x17E;e se ka&#x17E;d&#xE9; sn&#x11B;zen&#xE9; j&#xED;dlo nahrad&#xED; nov&#xFD;m.</p>\n<p>P&#x159;idej do t&#x159;&#xED;dy <code>State</code> n&#xE1;sleduj&#xED;c&#xED; novou metodu, kter&#xE1; um&#xED; p&#x159;idat j&#xED;dlo:</p>\n<div class=\"highlight\"><pre><span></span>    <span class=\"k\">def</span> <span class=\"nf\">add_food</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">x</span> <span class=\"o\">=</span> <span class=\"mi\">0</span>\n        <span class=\"n\">y</span> <span class=\"o\">=</span> <span class=\"mi\">0</span>\n        <span class=\"n\">position</span> <span class=\"o\">=</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">position</span><span class=\"p\">)</span>\n</pre></div><p>Pak tuhle metodu zavolej &#x2013; najdi v&#xA0;programu k&#xF3;d, kter&#xFD; se prov&#xE1;d&#xED; kdy&#x17E;\nje pot&#x159;eba p&#x159;idat nov&#xE9; j&#xED;dlo, a p&#x159;idej tam n&#xE1;sleduj&#xED;c&#xED; &#x159;&#xE1;dek:</p>\n<div class=\"highlight\"><pre><span></span>            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">add_food</span><span class=\"p\">()</span>\n</pre></div><p>Tahle metoda p&#x159;id&#xE1;v&#xE1; j&#xED;dlo na pozici (0, 0), tedy st&#xE1;le do stejn&#xE9;ho rohu.\nBylo by ale fajn, kdyby se nov&#xE9; j&#xED;dlo objevilo v&#x17E;dycky jinde,\nna n&#xE1;hodn&#xE9;m m&#xED;st&#x11B;.\nNa to m&#x16F;&#x17E;eme pou&#x17E;&#xED;t funkci <code>random.randrange</code>.\nVzpome&#x148; si, &#x17E;e vol&#xE1;n&#xED; <code>randrage(N)</code> vr&#xE1;t&#xED; n&#xE1;hodn&#xE9; cel&#xE9; &#x10D;&#xED;slo od\n0 do <var>N</var> - 1.</p>\n<p>Jak&#xFD; rozsah &#x10D;&#xED;sel pot&#x159;ebujeme pro had&#xED; j&#xED;dlo?</p>\n<p>A&#x17E; na to p&#x159;ijde&#x161;, zkus p&#x159;idat n&#xE1;hodu do programu: j&#xED;dlo by se m&#x11B;lo objevit\nna <em>&#xFA;pln&#x11B; n&#xE1;hjodn&#xE9;m</em> pol&#xED;&#x10D;ku na hern&#xED; plo&#x161;e.</p>\n<p>Nezapome&#x148; na <code>import random</code> &#x2013; to pat&#x159;&#xED; na &#xFA;pln&#xFD; za&#x10D;&#xE1;tek souboru.\nDal&#x161;&#xED; zm&#x11B;ny ale u&#x17E; d&#x11B;lej jen v&#xA0;metod&#x11B; <code>add_food</code>.</p>\n<div class=\"solution\" id=\"solution-6\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/6/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span>    <span class=\"k\">def</span> <span class=\"nf\">add_food</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"n\">x</span> <span class=\"o\">=</span> <span class=\"n\">random</span><span class=\"o\">.</span><span class=\"n\">randrange</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span><span class=\"p\">)</span>\n        <span class=\"n\">y</span> <span class=\"o\">=</span> <span class=\"n\">random</span><span class=\"o\">.</span><span class=\"n\">randrange</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span><span class=\"p\">)</span>\n        <span class=\"n\">position</span> <span class=\"o\">=</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">position</span><span class=\"p\">)</span>\n</pre></div>\n    </div>\n</div><p>A&#x17E; to bude&#x161; testovat, asi zjist&#xED;&#x161;, &#x17E;e <em>&#xFA;pln&#x11B; n&#xE1;hodn&#xE9;</em> pol&#xED;&#x10D;ko nen&#xED; ide&#xE1;ln&#xED;.\nOb&#x10D;as se  toti&#x17E; j&#xED;dlo objev&#xED; na pol&#xED;&#x10D;ku s&#xA0;hadem, nebo dokonce na jin&#xE9;m j&#xED;dle.\nJe proto dobr&#xE9; tuhle situaci zkontrolovat, a kdy&#x17E; volba padne na pln&#xE9; pol&#xED;&#x10D;ko,\nj&#xED;dlo nep&#x159;id&#xE1;vat:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"k\">if</span> <span class=\"p\">(</span><span class=\"n\">position</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">)</span> <span class=\"ow\">and</span> <span class=\"p\">(</span><span class=\"n\">position</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">):</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">position</span><span class=\"p\">)</span>\n</pre></div><p>Kdy&#x17E; ale zkus&#xED;&#x161; <em>tohle</em>, zjist&#xED;&#x161;, &#x17E;e ob&#x10D;as se nov&#xE9; j&#xED;dlo v&#x16F;bec nep&#x159;id&#xE1;.\nTo taky nen&#xED; vhodn&#xE1; varianta &#x2013; had by tak m&#x11B;l hlad.\nCo s&#xA0;t&#xED;m?</p>\n<p>P&#x159;ekvapiv&#x11B; dobr&#xE9; (i kdy&#x17E; ne <em>&#xFA;pln&#x11B;</em> ide&#xE1;ln&#xED;) &#x159;e&#x161;en&#xED; je zkusit pol&#xED;&#x10D;ko vybrat\nn&#x11B;kolikr&#xE1;t.\nKdy&#x17E; padne pr&#xE1;zdn&#xE9; pol&#xED;&#x10D;ko, &#x161;up tam s j&#xED;dlem; kdy&#x17E; padne pln&#xE9;, tak to\nprost&#x11B; zkusit znovu.</p>\n<p>Je ale pot&#x159;eba po&#x10D;et pokus&#x16F; omezit, aby v&#xA0;situaci, kdy je pole <em>&#xFA;pln&#x11B;</em> pln&#xE9;,\npo&#x10D;&#xED;ta&#x10D; nevyb&#xED;ral donekone&#x10D;na.\n&#x158;ekn&#x11B;me &#x17E;e kdy&#x17E; se na 100 pokus&#x16F; nepoda&#x159;&#xED; pr&#xE1;zdn&#xE9; pol&#xED;&#x10D;ko vybrat,\nvzd&#xE1;me to. J&#xED;dla u&#x17E; je nejsp&#xED;&#x161; dost.</p>\n<p>Metoda <code>add_food</code> po v&#x161;ech &#xFA;prav&#xE1;ch bude vypadat takhle:</p>\n<div class=\"highlight\"><pre><span></span>    <span class=\"k\">def</span> <span class=\"nf\">add_food</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"k\">for</span> <span class=\"n\">try_number</span> <span class=\"ow\">in</span> <span class=\"nb\">range</span><span class=\"p\">(</span><span class=\"mi\">100</span><span class=\"p\">):</span>\n            <span class=\"n\">x</span> <span class=\"o\">=</span> <span class=\"n\">random</span><span class=\"o\">.</span><span class=\"n\">randrange</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span><span class=\"p\">)</span>\n            <span class=\"n\">y</span> <span class=\"o\">=</span> <span class=\"n\">random</span><span class=\"o\">.</span><span class=\"n\">randrange</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span><span class=\"p\">)</span>\n            <span class=\"n\">position</span> <span class=\"o\">=</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span>\n            <span class=\"k\">if</span> <span class=\"p\">(</span><span class=\"n\">position</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">)</span> <span class=\"ow\">and</span> <span class=\"p\">(</span><span class=\"n\">position</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">):</span>\n                <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">position</span><span class=\"p\">)</span>\n                <span class=\"c1\"># Ukon&#x10D;en&#xED; funkce (&quot;vysko&#x10D;&#xED;&quot; i z cyklu for)</span>\n                <span class=\"k\">return</span>\n</pre></div><p>Jestli ti to funguje, je&#x161;t&#x11B; za&#x159;i&#x10F;, aby na za&#x10D;&#xE1;tku hry bylo j&#xED;dlo na n&#xE1;hodn&#xFD;ch\npozic&#xED;ch.</p>\n<div class=\"solution\" id=\"solution-7\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/7/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <p>V&#xA0;metod&#x11B; <code>__init__</code> se d&#xE1; m&#xED;sto nastaven&#xED; <code>self.food</code> na seznam s&#xA0;pozicemi\nj&#xED;dla napsat:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">add_food</span><span class=\"p\">()</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">add_food</span><span class=\"p\">()</span>\n</pre></div><p>Pak budou na za&#x10D;&#xE1;tku hry na hada &#x10D;ekat dv&#x11B; n&#xE1;hodn&#xE1; j&#xED;dla.</p>\n    </div>\n</div><h2>Konec</h2>\n<p>Had te&#x10F; m&#x16F;&#x17E;e nar&#x16F;st do obrovsk&#xFD;ch rozm&#x11B;r&#x16F; &#x2013; a lze prohr&#xE1;t jen t&#xED;m, &#x17E;e\nnaraz&#xED; do st&#x11B;ny.\nZa&#x159;&#xED;&#x10F; te&#x10F;, aby hra skon&#x10D;ila i kdy&#x17E; naraz&#xED; s&#xE1;m do sebe.</p>\n<p>Jak na to?\nDo metody <code>move</code>, vedle kontrola vylezen&#xED; z hrac&#xED; plochy,\ndej k&#xF3;d kter&#xFD; ud&#x11B;l&#xE1; n&#xE1;sleduj&#xED;c&#xED;:</p>\n<ul>\n<li>Pokud jsou sou&#x159;adnice nov&#xE9; hlavy u&#x17E; sou&#x10D;&#xE1;st hada:<ul>\n<li>Ukon&#x10D;i hru (podobn&#x11B; jako po n&#xE1;razu do st&#x11B;ny).</li>\n</ul>\n</li>\n</ul>\n<p>Dok&#xE1;&#x17E;e&#x161; to p&#x159;ev&#xE9;st do Pythonu?</p>\n<div class=\"solution\" id=\"solution-8\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/8/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span>        <span class=\"c1\"># Kontrola, jestli had narazil</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_head</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">:</span>\n            <span class=\"nb\">exit</span><span class=\"p\">(</span><span class=\"s1\">&apos;GAME OVER&apos;</span><span class=\"p\">)</span>\n</pre></div>\n    </div>\n</div><p>Hotovo!</p>\n<h3>Pauza</h3>\n<p>Nen&#xED; ale dobr&#xE9; p&#x159;i konci hry ukon&#x10D;it cel&#xFD; program a zav&#x159;&#xED;t ok&#xFD;nko.</p>\n<p>Lep&#x161;&#xED; je hru &#x201E;zapauzovat&#x201C; a uk&#xE1;zat hr&#xE1;&#x10D;i situaci, do kter&#xE9; ne&#x161;&#x165;astn&#xE9;ho hada\ndostal, aby se z n&#xED; mohl pro p&#x159;&#xED;&#x161;t&#x11B; pou&#x10D;it.</p>\n<p>Aby to bylo mo&#x17E;n&#xE9;, d&#xE1;me do stavu hry dal&#x161;&#xED; atribut: <code>alive</code>.\nTen bude nastaven&#xFD; na <code>True</code>, dokud bude had &#x17E;&#xED;t.\nKdy&#x17E; had naraz&#xED;, nastav&#xED; se na <code>False</code>, a od t&#xE9; doby se u&#x17E; nebude pohybovat.\nJe dobr&#xE9; i graficky uk&#xE1;zat, &#x17E;e hadovi nen&#xED; dob&#x159;e &#x2013; hr&#xE1;&#x10D; pak sp&#xED;&#x161; bude\nzpytovat sv&#x11B;dom&#xED;.</p>\n<p>Zkus zap&#x159;em&#xFD;&#x161;let, kam v&#xA0;k&#xF3;du pat&#x159;&#xED; n&#xE1;sleduj&#xED;c&#xED;\nkousky k&#xF3;du, kter&#xE9; prohru implementuj&#xED;:</p>\n<div class=\"highlight\"><pre><span></span>        <span class=\"c1\"># Prvotn&#xED; nastaven&#xED; atributu</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">True</span>\n</pre></div><div class=\"highlight\"><pre><span></span>        <span class=\"c1\"># Zastaven&#xED; hada</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">False</span>\n</pre></div><div class=\"highlight\"><pre><span></span>        <span class=\"c1\"># Zabr&#xE1;n&#x11B;n&#xED; pohybu</span>\n        <span class=\"k\">if</span> <span class=\"ow\">not</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span><span class=\"p\">:</span>\n            <span class=\"k\">return</span>\n</pre></div><div class=\"highlight\"><pre><span></span>        <span class=\"c1\"># Grafick&#xE1; indikace</span>\n        <span class=\"k\">if</span> <span class=\"n\">after</span> <span class=\"o\">==</span> <span class=\"s1\">&apos;end&apos;</span> <span class=\"ow\">and</span> <span class=\"ow\">not</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">alive</span><span class=\"p\">:</span>\n            <span class=\"n\">after</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;dead&apos;</span>\n</pre></div><div class=\"solution\" id=\"solution-9\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/9/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <ul>\n<li>&#x201E;Prvotn&#xED; nastaven&#xED; atributu&#x201C; do metody <code>__init__</code>.</li>\n<li>&#x201E;Zastaveni hada&#x201C; m&#xED;sto v&#x161;ech v&#xFD;skyt&#x16F; <code>raise(&quot;Game Over&quot;)</code>.</li>\n<li>&#x201E;Zabr&#xE1;n&#x11B;n&#xED; pohybu&#x201C; na &#xFA;pln&#xFD; za&#x10D;&#xE1;tek metody <code>move</code> (p&#x159;&#xED;kaz <code>return</code>\nokam&#x17E;it&#x11B; ukon&#x10D;&#xED; prov&#xE1;d&#x11B;n&#xED; metody).</li>\n<li>&#x201E;Grafick&#xE1; indikace&#x201C; za sekci pro vyb&#xED;r&#xE1;n&#xED; obr&#xE1;zku pro kousek\nhada.</li>\n</ul>\n    </div>\n</div><h2>A to je v&#x161;e?</h2>\n<p>Gratuluji, m&#xE1;&#x161; funk&#x10D;n&#xED; a hratelnou hru!\nDouf&#xE1;m &#x17E;e jsi na sebe hrd&#xE1;!</p>\n<p>Dej si n&#x11B;co sladk&#xE9;ho, zaslou&#x17E;&#xED;&#x161; si to.</p>\n<hr>\n<p>Tady je moje &#x159;e&#x161;en&#xED;.\nTo se touhle dobou od toho tv&#xE9;ho m&#x16F;&#x17E;e dost li&#x161;it &#x2013; to je &#xFA;pln&#x11B; norm&#xE1;ln&#xED;.\n(A ned&#xED;vej se sem dokud hada nenaprogramuje&#x161; sama,\nChybami a neust&#xE1;l&#xFD;m zkou&#x161;en&#xED;m se &#x10D;lov&#x11B;k u&#x10D;&#xED; &#x2013; a program&#xE1;tor zvl&#xE1;&#x161;&#x165;.\n&#x10C;ten&#xED;m u&#x17E; vy&#x159;e&#x161;en&#xE9;ho se u&#x10D;&#xED; h&#x16F;&#x159;.)</p>\n<div class=\"solution\" id=\"solution-10\">\n    <h3>&#x158;e&#x161;en&#xED;</h3>\n    <div class=\"solution-cover\">\n        <a href=\"/2019/brno-podzim-snake/snake/logic/index/solutions/10/\"><span class=\"link-text\">Uk&#xE1;zat &#x159;e&#x161;en&#xED;</span></a>\n    </div>\n    <div class=\"solution-body\" aria-hidden=\"true\">\n        <div class=\"highlight\"><pre><span></span><span class=\"kn\">import</span> <span class=\"nn\">random</span>\n<span class=\"kn\">from</span> <span class=\"nn\">pathlib</span> <span class=\"kn\">import</span> <span class=\"n\">Path</span>\n\n<span class=\"kn\">import</span> <span class=\"nn\">pyglet</span>\n\n<span class=\"n\">TILE_SIZE</span> <span class=\"o\">=</span> <span class=\"mi\">64</span>\n\n<span class=\"k\">class</span> <span class=\"nc\">State</span><span class=\"p\">:</span>\n    <span class=\"k\">def</span> <span class=\"fm\">__init__</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span> <span class=\"o\">=</span> <span class=\"p\">[(</span><span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">),</span> <span class=\"p\">(</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span><span class=\"p\">)]</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">1</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span> <span class=\"o\">=</span> <span class=\"mi\">10</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span> <span class=\"o\">=</span> <span class=\"mi\">10</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span> <span class=\"o\">=</span> <span class=\"p\">[]</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">add_food</span><span class=\"p\">()</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">add_food</span><span class=\"p\">()</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">True</span>\n\n    <span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"k\">if</span> <span class=\"ow\">not</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span><span class=\"p\">:</span>\n            <span class=\"k\">return</span>\n\n        <span class=\"n\">old_x</span><span class=\"p\">,</span> <span class=\"n\">old_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">]</span>\n        <span class=\"n\">dir_x</span><span class=\"p\">,</span> <span class=\"n\">dir_y</span> <span class=\"o\">=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span>\n        <span class=\"n\">new_x</span> <span class=\"o\">=</span> <span class=\"n\">old_x</span> <span class=\"o\">+</span> <span class=\"n\">dir_x</span>\n        <span class=\"n\">new_y</span> <span class=\"o\">=</span> <span class=\"n\">old_y</span> <span class=\"o\">+</span> <span class=\"n\">dir_y</span>\n\n        <span class=\"c1\"># Kontrola vylezen&#xED; z hrac&#xED; plochy</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">False</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_y</span> <span class=\"o\">&lt;</span> <span class=\"mi\">0</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">False</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_x</span> <span class=\"o\">&gt;=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">False</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_y</span> <span class=\"o\">&gt;=</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">False</span>\n\n        <span class=\"n\">new_head</span> <span class=\"o\">=</span> <span class=\"n\">new_x</span><span class=\"p\">,</span> <span class=\"n\">new_y</span>\n        <span class=\"k\">if</span> <span class=\"n\">new_head</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">alive</span> <span class=\"o\">=</span> <span class=\"bp\">False</span>\n        <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n\n        <span class=\"k\">if</span> <span class=\"n\">new_head</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">remove</span><span class=\"p\">(</span><span class=\"n\">new_head</span><span class=\"p\">)</span>\n            <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">add_food</span><span class=\"p\">()</span>\n        <span class=\"k\">else</span><span class=\"p\">:</span>\n            <span class=\"k\">del</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">[</span><span class=\"mi\">0</span><span class=\"p\">]</span>\n\n    <span class=\"k\">def</span> <span class=\"nf\">add_food</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"p\">):</span>\n        <span class=\"k\">for</span> <span class=\"n\">try_number</span> <span class=\"ow\">in</span> <span class=\"nb\">range</span><span class=\"p\">(</span><span class=\"mi\">100</span><span class=\"p\">):</span>\n            <span class=\"n\">x</span> <span class=\"o\">=</span> <span class=\"n\">random</span><span class=\"o\">.</span><span class=\"n\">randrange</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">width</span><span class=\"p\">)</span>\n            <span class=\"n\">y</span> <span class=\"o\">=</span> <span class=\"n\">random</span><span class=\"o\">.</span><span class=\"n\">randrange</span><span class=\"p\">(</span><span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">height</span><span class=\"p\">)</span>\n            <span class=\"n\">position</span> <span class=\"o\">=</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span>\n            <span class=\"k\">if</span> <span class=\"p\">(</span><span class=\"n\">position</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">)</span> <span class=\"ow\">and</span> <span class=\"p\">(</span><span class=\"n\">position</span> <span class=\"ow\">not</span> <span class=\"ow\">in</span> <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">):</span>\n                <span class=\"bp\">self</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"o\">.</span><span class=\"n\">append</span><span class=\"p\">(</span><span class=\"n\">position</span><span class=\"p\">)</span>\n                <span class=\"k\">return</span>\n\n<span class=\"n\">red_image</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">image</span><span class=\"o\">.</span><span class=\"n\">load</span><span class=\"p\">(</span><span class=\"s1\">&apos;apple.png&apos;</span><span class=\"p\">)</span>\n<span class=\"n\">snake_tiles</span> <span class=\"o\">=</span> <span class=\"p\">{}</span>\n<span class=\"k\">for</span> <span class=\"n\">start</span> <span class=\"ow\">in</span> <span class=\"p\">[</span><span class=\"s1\">&apos;bottom&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;end&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;left&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;right&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;top&apos;</span><span class=\"p\">]:</span>\n    <span class=\"k\">for</span> <span class=\"n\">end</span> <span class=\"ow\">in</span> <span class=\"p\">[</span><span class=\"s1\">&apos;bottom&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;end&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;left&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;right&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;top&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;dead&apos;</span><span class=\"p\">,</span> <span class=\"s1\">&apos;tongue&apos;</span><span class=\"p\">]:</span>\n        <span class=\"n\">key</span> <span class=\"o\">=</span> <span class=\"n\">start</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;-&apos;</span> <span class=\"o\">+</span> <span class=\"n\">end</span>\n        <span class=\"n\">image</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">image</span><span class=\"o\">.</span><span class=\"n\">load</span><span class=\"p\">(</span><span class=\"s1\">&apos;snake-tiles/&apos;</span> <span class=\"o\">+</span> <span class=\"n\">key</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;.png&apos;</span><span class=\"p\">)</span>\n        <span class=\"n\">snake_tiles</span><span class=\"p\">[</span><span class=\"n\">key</span><span class=\"p\">]</span> <span class=\"o\">=</span> <span class=\"n\">image</span>\n\n<span class=\"n\">window</span> <span class=\"o\">=</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">Window</span><span class=\"p\">()</span>\n\n<span class=\"n\">state</span> <span class=\"o\">=</span> <span class=\"n\">State</span><span class=\"p\">()</span>\n<span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">width</span> <span class=\"o\">=</span> <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">width</span> <span class=\"o\">//</span> <span class=\"n\">TILE_SIZE</span>\n<span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">height</span> <span class=\"o\">=</span> <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">height</span> <span class=\"o\">//</span> <span class=\"n\">TILE_SIZE</span>\n\n\n<span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_draw</span><span class=\"p\">():</span>\n    <span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">clear</span><span class=\"p\">()</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glEnable</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_BLEND</span><span class=\"p\">)</span>\n    <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">glBlendFunc</span><span class=\"p\">(</span><span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_SRC_ALPHA</span><span class=\"p\">,</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">gl</span><span class=\"o\">.</span><span class=\"n\">GL_ONE_MINUS_SRC_ALPHA</span><span class=\"p\">)</span>\n    <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake</span><span class=\"p\">:</span>\n        <span class=\"n\">before</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;end&apos;</span>     <span class=\"c1\"># (Tady p&#x159;&#xED;padn&#x11B; je n&#x11B;jak&#xE9;</span>\n        <span class=\"n\">after</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;end&apos;</span>      <span class=\"c1\">#  slo&#x17E;it&#x11B;j&#x161;&#xED; vyb&#xED;r&#xE1;n&#xED; pol&#xED;&#x10D;ka)</span>\n        <span class=\"k\">if</span> <span class=\"n\">after</span> <span class=\"o\">==</span> <span class=\"s1\">&apos;end&apos;</span> <span class=\"ow\">and</span> <span class=\"ow\">not</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">alive</span><span class=\"p\">:</span>\n            <span class=\"n\">after</span> <span class=\"o\">=</span> <span class=\"s1\">&apos;dead&apos;</span>\n        <span class=\"n\">snake_tiles</span><span class=\"p\">[</span><span class=\"n\">before</span> <span class=\"o\">+</span> <span class=\"s1\">&apos;-&apos;</span> <span class=\"o\">+</span> <span class=\"n\">after</span><span class=\"p\">]</span><span class=\"o\">.</span><span class=\"n\">blit</span><span class=\"p\">(</span>\n            <span class=\"n\">x</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">width</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">height</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">)</span>\n    <span class=\"k\">for</span> <span class=\"n\">x</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"ow\">in</span> <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">food</span><span class=\"p\">:</span>\n        <span class=\"n\">red_image</span><span class=\"o\">.</span><span class=\"n\">blit</span><span class=\"p\">(</span>\n            <span class=\"n\">x</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">y</span> <span class=\"o\">*</span> <span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">width</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">,</span> <span class=\"n\">height</span><span class=\"o\">=</span><span class=\"n\">TILE_SIZE</span><span class=\"p\">)</span>\n\n\n<span class=\"nd\">@window.event</span>\n<span class=\"k\">def</span> <span class=\"nf\">on_key_press</span><span class=\"p\">(</span><span class=\"n\">key_code</span><span class=\"p\">,</span> <span class=\"n\">modifier</span><span class=\"p\">):</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">LEFT</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"o\">-</span><span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">RIGHT</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">1</span><span class=\"p\">,</span> <span class=\"mi\">0</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">DOWN</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"o\">-</span><span class=\"mi\">1</span>\n    <span class=\"k\">if</span> <span class=\"n\">key_code</span> <span class=\"o\">==</span> <span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">window</span><span class=\"o\">.</span><span class=\"n\">key</span><span class=\"o\">.</span><span class=\"n\">UP</span><span class=\"p\">:</span>\n        <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">snake_direction</span> <span class=\"o\">=</span> <span class=\"mi\">0</span><span class=\"p\">,</span> <span class=\"mi\">1</span>\n\n\n<span class=\"k\">def</span> <span class=\"nf\">move</span><span class=\"p\">(</span><span class=\"n\">dt</span><span class=\"p\">):</span>\n    <span class=\"n\">state</span><span class=\"o\">.</span><span class=\"n\">move</span><span class=\"p\">()</span>\n\n\n<span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">clock</span><span class=\"o\">.</span><span class=\"n\">schedule_interval</span><span class=\"p\">(</span><span class=\"n\">move</span><span class=\"p\">,</span> <span class=\"mi\">1</span><span class=\"o\">/</span><span class=\"mi\">6</span><span class=\"p\">)</span>\n\n<span class=\"n\">pyglet</span><span class=\"o\">.</span><span class=\"n\">app</span><span class=\"o\">.</span><span class=\"n\">run</span><span class=\"p\">()</span>\n</pre></div>\n    </div>\n</div><h2>Co d&#xE1;l?</h2>\n<p>Najde&#x161; je&#x161;t&#x11B; n&#x11B;jak&#xE9; dal&#x161;&#xED; vylep&#x161;en&#xED;, kter&#xE9; by se dalo ud&#x11B;lat?</p>\n<p>Zkus t&#x159;eba n&#xE1;sleduj&#xED;c&#xED; roz&#x161;&#xED;&#x159;en&#xED;. Jsou se&#x159;azen&#xE9; zhruba podle slo&#x17E;itosti:</p>\n<ul>\n<li><p>Vylep&#x161;i ovl&#xE1;d&#xE1;n&#xED; (a hratelnost!) podle <a href=\"/2019/brno-podzim-snake/snake/handling/\">n&#xE1;vodu</a>.</p>\n</li>\n<li><p>Ka&#x17E;d&#xFD;ch 30 vte&#x159;in hry p&#x159;ibude samo od sebe nov&#xE9; j&#xED;dlo,\ntak&#x17E;e jich pak bude na hrac&#xED; plo&#x161;e v&#xED;c.</p>\n</li>\n<li><p>Hra se bude postupn&#x11B; zrychlovat.<br>\n<em>(Na to je nejlep&#x161;&#xED; p&#x159;ed&#x11B;lat funkci <code>move</code>, aby </em>sama<em>\nnapl&#xE1;novala, kdy se m&#xE1; p&#x159;&#xED;&#x161;t&#x11B; zavolat. Vol&#xE1;n&#xED; <code>schedule_interval</code> tak u&#x17E;\nnebude pot&#x159;eba.)</em></p>\n</li>\n<li><p>Kdy&#x17E; had vyleze ven z ok&#xFD;nka, m&#xED;sto konce hry se objev&#xED; na druh&#xE9; stran&#x11B;.\n(Viz <a href=\"/2019/brno-podzim-snake/snake/toroid/\">n&#xE1;vod</a>.)</p>\n</li>\n<li><p>Hadi budou dva; druh&#xFD; se ovl&#xE1;d&#xE1; kl&#xE1;vesami\n<kbd>W</kbd> <kbd>A</kbd> <kbd>S</kbd> <kbd>D</kbd>.<br>\n<em>(Na to je nejlep&#x161;&#xED; ud&#x11B;lat novou t&#x159;&#xED;du, <code>Snake</code>, a v&#x161;echen stav hada\np&#x159;esunout ze <code>State</code> do n&#xED;. Ve <code>State</code> pak m&#x11B;j seznam had&#x16F;.\nT&#xE9;hle zm&#x11B;n&#x11B; je pot&#x159;eba p&#x159;izp&#x16F;sobit cel&#xFD; zytek programu.)</em></p>\n</li>\n</ul>\n\n\n        "
    }
  }
}