cfreshman · May 8, 2024 13:37 · guestpostingagency799-lgtm · Aug 16, 2026 · horaihero1 · Aug 19, 2026
diff --git a/snake_ultra_hydra.html b/snake_ultra_hydra.html
 <!DOCTYPE html>
 <html>
  <head>
    <meta charset=utf-8>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    <title>snake ultra hydra</title>
    <link rel="icon" href="https://i.guim.co.uk/img/media/993cc4a2107b870f78d1228874906ad9646fb204/0_144_2160_1296/master/2160.jpg?width=1200&height=1200&quality=85&auto=format&fit=crop&s=708569290282f1d206da9d72d5c2046c">
    <style>body{display:flex;flex-direction:column;margin:.5em;font-family:system-ui}</style>
    <style>
      #game-canvas {
        image-rendering: pixelated;
        /* 30rem by default, but shrink to window height w/ .5em margin */
        width: min(30rem, calc(100vh - 1em));
        height: min(30rem, calc(100vh - 1em));
      }
    </style>
    <script>
      // COMMON CODE

      // truthy: interpret the value as a boolean
      const truthy = x => Boolean(x)

      // V2: a two-dimensional vector value
      // - add: add to another vector
      // - equals: check if this vector equals another vector (e.g. same position)
      class V2 {
        constructor(x_or_vector, y) {
          let x, vector
          if (typeof x_or_vector === 'number') {
            x = x_or_vector
          } else {
            vector = x_or_vector
          }
          if (vector) {
            // allow copying another vector 
            this.x = vector.x
            this.y = vector.y
          } else {
            this.x = x
            this.y = y
          }
        }
        add(other) {
          return new V2(this.x + other.x, this.y + other.y)
        }
        equals(other) {
          return this.x === other.x && this.y === other.y
        }
      }

      // ListNode: linked list implementation
      // store reference to first node to access entire list
      class ListNode {
        constructor(value, next) {
          this.value = value
          this.next = next
        }
        map(func) {
          let curr = this
          const results = []
          while (curr) {
            results.push(func(curr.value))
            curr = curr.next
          }
          return results
        }
      }
    </script>
  </head>
  <body>

    <div>
      WASD or ARROW KEYS to move. any other key to reset
    </div>
    <canvas id="game-canvas"></canvas>
    <div>
      (DESKTOP ONLY)
    </div>

    <script>
      // board size 20x20 pixels
      const SIZE = 20
      // cardinal directions the snake can move in
      const DIRS = {
        RIGHT: new V2(1, 0),
        UP: new V2(0, -1),
        LEFT: new V2(-1, 0),
        DOWN: new V2(0, 1),
      }

      // set the canvas to SIZE width and height
      const canvas = document.querySelector('#game-canvas')
      canvas.width = canvas.height = SIZE
      // get the canvas graphics context for drawing the game pixels
      const ctx = canvas.getContext('2d')
      // game colors
      const COLORS = {
        BACKGROUND: '#000000',
        SNAKE: '#34eb7d',
        APPLE: '#ff0000',
      }

      // Pixel: a drawable position
      // - draw: draw a colored square at this position
      // - randomize: move pixel to random position
      class Pixel extends V2 {
        constructor(x, y, color) {
          super(x, y)
          this.color = color
        }
        draw(ctx, color) {
          ctx.fillStyle = color
          ctx.fillRect(this.x, this.y, 1, 1)
          return this
        }
        randomize() {
          this.x = Math.floor(Math.random() * SIZE)
          this.y = Math.floor(Math.random() * SIZE)
          return this
        }
      }

      // snake behaviors/functions
      function snake_move(head, dir, do_grow=false) {
        // moving the snake:
        // body nodes don't actually change
        // a new head is added to the front (in input direction)
        // if the snake isn't growing, the last node is removed
        const new_head = new ListNode(new Pixel(head.value.x + dir.x, head.value.y + dir.y, head.color), head)
        if (!do_grow) {
          let curr = head
          while (curr.next.next) curr = curr.next
          curr.next = undefined
        }
        return new_head
      }
      function snake_intersects(head, position) {
        // true if any body parts are placed at the position
        return head ? head.map(part => part.equals(position)).some(truthy) : false
      }

      // === GAME STATE ===
      // start the snake heading towards the right
      let head = new ListNode(new Pixel(SIZE/4, SIZE/2, COLORS.SNAKE))
      let direction = DIRS.RIGHT
      // how many new segments to grow
      let growth = 2
      // place the apple at a random position
      const apple = new Pixel(0, 0, COLORS.APPLE).randomize()
      // is the game over
      let gameover = false
      // last is used to avoid letting the snake do a 180
      let last = direction

      // === GAME LOOP ===
      function loop() {
        if (gameover) return
        // we check against 'last' in the input handler to prevent a 180
        // 'last' allows us to update direction immediately but always check the new direction against the actual last direction
        last = direction

        // move the snake
        // gameover if snake intersects itself or went out of bounds
        head = snake_move(head, direction, growth)
        if (growth > 0) growth--
        if (snake_intersects(head.next, head.value)
          || head.value.x < 0 || head.value.x > SIZE-1
          || head.value.y < 0 || head.value.y > SIZE-1) {
          gameover = true
          return
        }

        // check if the head is at the same position as the apple
        // if so, grow the body and move the apple to a new location
        if (head.value.equals(apple)) {
          growth += 1
          do {
            apple.randomize()
          } while (snake_intersects(head, apple))
        }

        // draw the scene:
        // 1) cover the entire scene with black
        // 2) fill each snake segment with green
        // 3) fill the apple position with red
        ctx.fillStyle = COLORS.BACKGROUND
        ctx.fillRect(0, 0, SIZE, SIZE)
        head.map(part => part.draw(ctx, COLORS.SNAKE))
        apple.draw(ctx, COLORS.APPLE)
      }

      // === GAME INPUT ===
      // listen for pressed keys to re-direct the snake
      window.addEventListener('keydown', e => {
        switch (e.key) {
          case 'w': case 'ArrowUp':
            if (last !== DIRS.DOWN) direction = DIRS.UP
            break
          case 'a': case 'ArrowLeft':
            if (last !== DIRS.RIGHT) direction = DIRS.LEFT
            break
          case 's': case 'ArrowDown':
            if (last !== DIRS.UP) direction = DIRS.DOWN
            break
          case 'd': case 'ArrowRight':
            if (last !== DIRS.LEFT) direction = DIRS.RIGHT
            break
          default:
            if (gameover) location.reload()
            break
        }
      })

      // run loop() 10 times per second (every 100ms) (snake moves 10 cells/sec)
      setInterval(loop, 100)

    </script>
  </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset=utf-8>
	<meta name="viewport" content="width=device-width, initial-scale=1.0">

	<title>snake ultra hydra</title>
	<link rel="icon" href="https://i.guim.co.uk/img/media/993cc4a2107b870f78d1228874906ad9646fb204/0_144_2160_1296/master/2160.jpg?width=1200&height=1200&quality=85&auto=format&fit=crop&s=708569290282f1d206da9d72d5c2046c">
	<style>body{display:flex;flex-direction:column;margin:.5em;font-family:system-ui}</style>
	<style>
	#game-canvas {
	image-rendering: pixelated;
	/* 30rem by default, but shrink to window height w/ .5em margin */
	width: min(30rem, calc(100vh - 1em));
	height: min(30rem, calc(100vh - 1em));
	}
	</style>
	<script>
	// COMMON CODE

	// truthy: interpret the value as a boolean
	const truthy = x => Boolean(x)

	// V2: a two-dimensional vector value
	// - add: add to another vector
	// - equals: check if this vector equals another vector (e.g. same position)
	class V2 {
	constructor(x_or_vector, y) {
	let x, vector
	if (typeof x_or_vector === 'number') {
	x = x_or_vector
	} else {
	vector = x_or_vector
	}
	if (vector) {
	// allow copying another vector
	this.x = vector.x
	this.y = vector.y
	} else {
	this.x = x
	this.y = y
	}
	}
	add(other) {
	return new V2(this.x + other.x, this.y + other.y)
	}
	equals(other) {
	return this.x === other.x && this.y === other.y
	}
	}

	// ListNode: linked list implementation
	// store reference to first node to access entire list
	class ListNode {
	constructor(value, next) {
	this.value = value
	this.next = next
	}
	map(func) {
	let curr = this
	const results = []
	while (curr) {
	results.push(func(curr.value))
	curr = curr.next
	}
	return results
	}
	}
	</script>
	</head>
	<body>

	<div>
	WASD or ARROW KEYS to move. any other key to reset
	</div>
	<canvas id="game-canvas"></canvas>
	<div>
	(DESKTOP ONLY)
	</div>

	<script>
	// board size 20x20 pixels
	const SIZE = 20
	// cardinal directions the snake can move in
	const DIRS = {
	RIGHT: new V2(1, 0),
	UP: new V2(0, -1),
	LEFT: new V2(-1, 0),
	DOWN: new V2(0, 1),
	}

	// set the canvas to SIZE width and height
	const canvas = document.querySelector('#game-canvas')
	canvas.width = canvas.height = SIZE
	// get the canvas graphics context for drawing the game pixels
	const ctx = canvas.getContext('2d')
	// game colors
	const COLORS = {
	BACKGROUND: '#000000',
	SNAKE: '#34eb7d',
	APPLE: '#ff0000',
	}

	// Pixel: a drawable position
	// - draw: draw a colored square at this position
	// - randomize: move pixel to random position
	class Pixel extends V2 {
	constructor(x, y, color) {
	super(x, y)
	this.color = color
	}
	draw(ctx, color) {
	ctx.fillStyle = color
	ctx.fillRect(this.x, this.y, 1, 1)
	return this
	}
	randomize() {
	this.x = Math.floor(Math.random() * SIZE)
	this.y = Math.floor(Math.random() * SIZE)
	return this
	}
	}

	// snake behaviors/functions
	function snake_move(head, dir, do_grow=false) {
	// moving the snake:
	// body nodes don't actually change
	// a new head is added to the front (in input direction)
	// if the snake isn't growing, the last node is removed
	const new_head = new ListNode(new Pixel(head.value.x + dir.x, head.value.y + dir.y, head.color), head)
	if (!do_grow) {
	let curr = head
	while (curr.next.next) curr = curr.next
	curr.next = undefined
	}
	return new_head
	}
	function snake_intersects(head, position) {
	// true if any body parts are placed at the position
	return head ? head.map(part => part.equals(position)).some(truthy) : false
	}

	// === GAME STATE ===
	// start the snake heading towards the right
	let head = new ListNode(new Pixel(SIZE/4, SIZE/2, COLORS.SNAKE))
	let direction = DIRS.RIGHT
	// how many new segments to grow
	let growth = 2
	// place the apple at a random position
	const apple = new Pixel(0, 0, COLORS.APPLE).randomize()
	// is the game over
	let gameover = false
	// last is used to avoid letting the snake do a 180
	let last = direction

	// === GAME LOOP ===
	function loop() {
	if (gameover) return
	// we check against 'last' in the input handler to prevent a 180
	// 'last' allows us to update direction immediately but always check the new direction against the actual last direction
	last = direction

	// move the snake
	// gameover if snake intersects itself or went out of bounds
	head = snake_move(head, direction, growth)
	if (growth > 0) growth--
	if (snake_intersects(head.next, head.value)
	\|\| head.value.x < 0 \|\| head.value.x > SIZE-1
	\|\| head.value.y < 0 \|\| head.value.y > SIZE-1) {
	gameover = true
	return
	}

	// check if the head is at the same position as the apple
	// if so, grow the body and move the apple to a new location
	if (head.value.equals(apple)) {
	growth += 1
	do {
	apple.randomize()
	} while (snake_intersects(head, apple))
	}

	// draw the scene:
	// 1) cover the entire scene with black
	// 2) fill each snake segment with green
	// 3) fill the apple position with red
	ctx.fillStyle = COLORS.BACKGROUND
	ctx.fillRect(0, 0, SIZE, SIZE)
	head.map(part => part.draw(ctx, COLORS.SNAKE))
	apple.draw(ctx, COLORS.APPLE)
	}

	// === GAME INPUT ===
	// listen for pressed keys to re-direct the snake
	window.addEventListener('keydown', e => {
	switch (e.key) {
	case 'w': case 'ArrowUp':
	if (last !== DIRS.DOWN) direction = DIRS.UP
	break
	case 'a': case 'ArrowLeft':
	if (last !== DIRS.RIGHT) direction = DIRS.LEFT
	break
	case 's': case 'ArrowDown':
	if (last !== DIRS.UP) direction = DIRS.DOWN
	break
	case 'd': case 'ArrowRight':
	if (last !== DIRS.LEFT) direction = DIRS.RIGHT
	break
	default:
	if (gameover) location.reload()
	break
	}
	})

	// run loop() 10 times per second (every 100ms) (snake moves 10 cells/sec)
	setInterval(loop, 100)

	</script>
	</body>
	</html>
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