WASM4 Snake

Hint: Snake game in Yaksha for WASM4 (ported)

import w4
import libs.random

class Point:
    # Point (x, y)
    x: i16
    y: i16

class Snake:
    # Snake's body and direction
    body: Array[Point]
    direction: Point

class State:
    # Game state
    snake: Snake
    fruit_sprite: Ptr[Const[u8]]
    fruit: Point
    frame_count: u32
    gamepad_prev: u8

def point(x: i16, y: i16) -> Point:
    my_point: Point = Point()
    my_point.x = x
    my_point.y = y
    return my_point

def set_random_point(p: Point) -> Point:
    x: i16 = cast("i16", random.random_u64() % 20u64)
    y: i16 = cast("i16", random.random_u64() % 20u64)
    p.x = x
    p.y = y

def random_point() -> Point:
    p: Point = Point()
    return set_random_point(p)

def draw_snake(snake: Snake) -> None:
    # Body
    w4.set_draw_colors(0x0043u16)
    i: int = 0
    while i < len(snake.body):
        body_part: Point = snake.body[i]
        x: int = cast("int", body_part.x * 8i16)
        y: int = cast("int", body_part.y * 8i16)
        w4.rect(x, y, 8u32, 8u32)
        i += 1
    # Head
    w4.set_draw_colors(0x0004u16)
    body_part: Point = snake.body[0]
    x: int = cast("int", body_part.x * 8i16)
    y: int = cast("int", body_part.y * 8i16)
    w4.rect(x, y, 8u32, 8u32)

def snake_push(snake: Snake, p: Point) -> None:
    arrput(snake.body, p)

def snake_update(snake: Snake) -> None:
    # Move snake a level up
    position: int = len(snake.body) - 1
    while position > 0:
        snake.body[position].x = snake.body[position - 1].x
        snake.body[position].y = snake.body[position - 1].y
        position -= 1
    snake.body[0].x = (snake.body[0].x + snake.direction.x) % 20i16
    snake.body[0].y = (snake.body[0].y + snake.direction.y) % 20i16
    if snake.body[0].x < 0i16:
        snake.body[0].x = 19i16
    if snake.body[0].y < 0i16:
        snake.body[0].y = 19i16

def snake_up(snake: Snake) -> None:
    if snake.direction.y == 0i16:
        snake.direction.x = 0i16
        snake.direction.y = -1i16

def snake_down(snake: Snake) -> None:
    if snake.direction.y == 0i16:
        snake.direction.x = 0i16
        snake.direction.y = 1i16

def snake_left(snake: Snake) -> None:
    if snake.direction.x == 0i16:
        snake.direction.x = -1i16
        snake.direction.y = 0i16

def snake_right(snake: Snake) -> None:
    if snake.direction.x == 0i16:
        snake.direction.x = 1i16
        snake.direction.y = 0i16

def snake_isdead(snake: Snake) -> bool:
    part: int = 1
    while part < len(snake.body):
        if snake.body[part].x == snake.body[0].x and snake.body[part].y == snake.body[0].y:
            return True
        part += 1
    return False

def del_point(p: Point, ignored: int) -> bool:
    del p
    return True

def snake_reset(snake: Snake) -> None:
    foreach(snake.body, del_point, 0)
    del snake.body
    body: Array[Point]
    arrput(body, point(2i16, 0i16))
    arrput(body, point(1i16, 0i16))
    arrput(body, point(0i16, 0i16))
    snake.body = body
    snake.direction.x = 1i16
    snake.direction.y = 0i16

def handle_input(state: State) -> None:
    just_pressed: u8 = w4.gamepad1() & (w4.gamepad1() ^ state.gamepad_prev)
    if just_pressed & w4.BUTTON_UP != 0u8:
        snake_up(state.snake)
    if just_pressed & w4.BUTTON_DOWN != 0u8:
        snake_down(state.snake)
    if just_pressed & w4.BUTTON_LEFT != 0u8:
        snake_left(state.snake)
    if just_pressed & w4.BUTTON_RIGHT != 0u8:
        snake_right(state.snake)
    state.gamepad_prev = w4.gamepad1()

def game_step(data: AnyPtr) -> None:
    state: State = cast("State", data)
    state.frame_count += 1u32
    random.set_seed(cast("u64", state.frame_count))
    x: int = 8 * cast("int", state.fruit.x)
    y: int = 8 * cast("int", state.fruit.y)

    handle_input(state)
    if state.frame_count % 15u32 == 0u32:
        snake_update(state.snake)
        if snake_isdead(state.snake):
            snake_reset(state.snake)
            state.fruit = set_random_point(state.fruit)
        # Ate fruit
        if state.snake.body[0].x == state.fruit.x and state.snake.body[0].y == state.fruit.y:
            penultimate: int = len(state.snake.body) - 1
            snake_push(state.snake, point(state.snake.body[penultimate].x, state.snake.body[penultimate].y))
            state.fruit = set_random_point(state.fruit)

    draw_snake(state.snake)
    # Draw sprite
    w4.set_draw_colors(0x4320u16)
    w4.blit(state.fruit_sprite, x, y, 8u32, 8u32, w4.BLIT_2BPP)

def main() -> int:
    random.set_seed(0x20u64)
    w4.set_palette(0xfbf7f3u32, 0xe5b083u32, 0x426e5du32, 0x20283du32)
    state: State = State()
    state.snake = Snake()
    state.fruit = point(10i16, 8i16)
    state.snake.direction = point(1i16, 0i16)
    state.frame_count = 0u32
    state.gamepad_prev = 0u8
    body: Array[Point]
    arrput(body, point(2i16, 0i16))
    arrput(body, point(1i16, 0i16))
    arrput(body, point(0i16, 0i16))
    state.snake.body = body
    state.fruit_sprite = binarydata("\x00\xa0\x02\x00\x0e\xf0\x36\x5c\xd6\x57\xd5\x57\x35\x5c\x0f\xf0")
    w4.set_game_state(cast("AnyPtr", state))
    return 0