NodesNim/examples/snake/main.nim

import nodesnim
import random
randomize()


Window("Snake game")


type
  Snake = ref object
    dir: Vector2Ref
    size: Vector2Ref
    food: Vector2Ref
    body: seq[Vector2Ref]


var
  main = Scene("Main")

  canvas = Canvas("Canvas")

  snake = Snake(
    dir: Vector2(),
    body: @[Vector2(0, 0)],
    size: Vector2(40, 40),
    food: Vector2(160, 160))
  time = 0

Input.addKeyAction("forward", "w")
Input.addKeyAction("backward", "s")
Input.addKeyAction("left", "a")
Input.addKeyAction("right", "d")


canvas.process =
  proc() =
    if Input.isActionJustPressed("forward"):
      snake.dir = Vector2(0, -40)
    elif Input.isActionJustPressed("backward"):
      snake.dir = Vector2(0, 40)
    elif Input.isActionJustPressed("left"):
      snake.dir = Vector2(-40, 0)
    elif Input.isActionJustPressed("right"):
      snake.dir = Vector2(40, 0)
    if time < 10:
      inc time
      return
    canvas.resize(main.rect_size.x, main.rect_size.y)
    let
      grid_size = Vector2(
        (main.rect_size.x.int div snake.size.x.int).float,
        (main.rect_size.y.int div snake.size.y.int).float
      )
    canvas.fill(Color(0, 0, 0, 0))


    if snake.dir.y < 0:
      for i in countdown(snake.body.len()-1, 0):
        if i > 0:
          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
        else:
          if snake.body[i].y > 0:
            snake.body[i].y += snake.dir.y
          else:
            snake.body[i].y = grid_size.y*snake.size.y - snake.size.y
    elif snake.dir.y > 0:
      for i in countdown(snake.body.len()-1, 0):
        if i > 0:
          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
        else:
          if snake.body[i].y < grid_size.y*snake.size.y - snake.size.y:
            snake.body[i].y += snake.dir.y
          else:
            snake.body[i].y = 0

    elif snake.dir.x < 0:
      for i in countdown(snake.body.len()-1, 0):
        if i > 0:
          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
        else:
          if snake.body[i].x > 0:
            snake.body[i].x += snake.dir.x
          else:
            snake.body[i].x = grid_size.x*snake.size.x - snake.size.x
    elif snake.dir.x > 0:
      for i in countdown(snake.body.len()-1, 0):
        if i > 0:
          snake.body[i] = Vector2(snake.body[i-1].x, snake.body[i-1].y)
        else:
          if snake.body[i].x < grid_size.x*snake.size.x - snake.size.x:
            snake.body[i].x += snake.dir.x
          else:
            snake.body[i].x = 0

    if snake.body[0] == snake.food:
      snake.body.add(snake.body[^1])
      snake.food.x = (rand(grid_size.x.int-1) * snake.size.x.int).float
      snake.food.y = (rand(grid_size.y.int-1) * snake.size.y.int).float

    # draw
    for i in snake.body:
      canvas.rect(i.x, i.y, i.x+snake.size.x, i.y+snake.size.y, Color(1f, 1f, 1f))
    # head
    canvas.rect(
      snake.body[0].x, snake.body[0].y,
      snake.body[0].x+snake.size.x, snake.body[0].y+snake.size.y,
      Color(0xaaccffff'u32))
    # food
    canvas.rect(
      snake.food.x, snake.food.y,
      snake.food.x+snake.size.x, snake.food.y+snake.size.y,
      Color(0xffccaaff'u32))
    time = 0


main.addChild(canvas)
addScene(main)
setMainScene("Main")
windowLaunch()