giftrun.js

/*
Giftrun

MIT License

Copyright (c) 2009 Ole Martin Bjorndalen

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
 */

SKY_COLOR = '#b4b4ff';
NUM_SNOWFLAKES = 10;

image_names = ['reindeer1',
	       'reindeer2',
	       'rudolph1',
	       'rudolph2',
	       'santa1',
	       'santa2',
	       'santa3',
	       'chimney',
	       'gift',
	       'splat',
	       'star',
	       'smoke1',
	       'smoke2',
	       'poof',
	       'snowflake'];

sound_names = ['plingeling',
	       'poof',
	       'whistle',
	       'splat']

images = {};
sounds = {};

move_left = false;
move_right = false;
move_up = false;
move_down = false;
move_drop = false;

play_sounds = true;
play_music = false;

// 2D vector class (really basic)
// Used for positions and motion.
function Vec2(x, y) {
    this.x = x;
    this.y = y;

    this.add = function(other) {
	this.x += other.x;
	this.y += other.y;
    }

    this.copy = function() {
	return new Vec2(this.x, this.y);
    }
}

function vec(x, y) {
    return new Vec2(x, y);
}

// Call function for each element in the array
// and remove it if the function returns true.
// The list is iterated in reverse order.
function removeif(arr, func)
{
    for(var i=arr.length-1; i >= 0; i--) {
	if(func(arr[i])) {
	    arr.splice(i, 1);
	}
    }
}

// Call function for every item in list
function iter(arr, func)
{
    for(var i=0; i < arr.length; i++) {
	func(arr[i]);
    }
}

function randint(high)
{
    return Math.floor(Math.random() * high);
}

function randrange(low, high)
{
    return low + Math.floor(Math.random() * high);
}

function Sprite(pos, motion, image) {
    this.pos = pos;
    this.motion = motion;
    this.image = image;

    this.move = function(speed) {
	this.pos.x += speed;
	this.pos.add(this.motion);
    }

    this.draw = function() {
	ctx.drawImage(images[this.image], this.pos.x, this.pos.y);
    }
}

function House(pos, motion, image) {
    this.superClass = Sprite;
    this.superClass(pos, motion, image);
    this.smoking = (randint(4) == 0);  // 1 of 4 houses smoke
}

// Reindeer or Santa
function Character(pos, motion, image) {
    this.superClass = Sprite;
    this.superClass(pos, motion, image);

    this.move = function(speed) {
	// Characters don't move this way
    }
}

function Santa(pos, motion, image) {
    this.superClass = Sprite;
    this.superClass(pos, motion, image);
}

function Gift(pos, motion, image) {
    this.superClass = Sprite;
    this.superClass(pos, motion, image);

    this.move = function(speed) {
	this.motion.y += 0.5;
	this.pos.x += speed;
	this.pos.add(this.motion);
    }
}

function load_data(onload) {
    var remaining = image_names.length + sound_names.length;
    var onload = function() {
	remaining -= 1;
	if(remaining == 0) {
	    onload();
	}
    }

    for(i in image_names) {
	var name = image_names[i];
	var img = new Image();
	img.onload = onload;
	img.src = "images/" + name + ".png";
	images[name] = img;
    };

    for(i in sound_names) {
	var name = sound_names[i];
	var snd = new Audio();
	snd.onload = onload;
	snd.src = "sounds/" + name + ".wav";
	snd.load();
	sounds[name] = snd;
    };
}

whistle_sound = null;

function play_sound(name)
{
    if(play_sounds) {
	// Stop whistle sound if it is playing
	if(whistle_sound) {
 	    whistle_sound.pause();
	    delete whistle_sound;
	    whistle_sound = null;
	}
	
	if(sounds[name]) {
	    var url = sounds[name].src;
	    var a = new Audio(url);
	    a.load();
	    a.play();

	    if(name == 'whistle') {
		whistle_sound = a;
	    }
	}
    }
}

frame = 1;
deer = 0;

rudolph = new Character(vec(146, 180), vec(0, 0), 'rudolph1');
reindeer = new Character(vec(246, 180), vec(0, 0), 'reindeer1');
santa = new Character(vec(336, 170), vec(0, 0), 'santa1');

houses = [];
snowflakes = [];
gifts = [];
things = [];  // Smoke, puffs, stars and splatted gifts

next_house_in = 0;

function Timer() {
    this.now = 0;
    this.todo = [];
    
    this.timekey = function(n) {
	return "at" + n;
    }

    this.after = function(ticks, func) {
	var key = this.timekey(this.now + ticks);
	if(!this.todo[key]) {
	    this.todo[key] = [];
	}
	this.todo[key].push(func);
    }
    
    this.tick = function() {
	this.now += 1;
	var key = this.timekey(this.now);
	
	if(this.todo[key]) {
	    for(var i in this.todo[key]) {
		this.todo[key][i]();
	    }
	    delete this.todo[key];
	}
    }
}

timer = new Timer();

function animate()
{
    setTimeout("animate()", 33);

    timer.tick();

    ctx.fillStyle = SKY_COLOR;
    ctx.fillRect(0, 0, WIDTH, HEIGHT);

    var motion = vec(0, 0);
    var x = rudolph.pos.x;
    var y = rudolph.pos.y;

    if(move_left && x > 10) {
	motion.x -= 10;
    }

    if(move_right && x < (WIDTH-340)) {
	motion.x += 10;
    }

    if(move_up && y > 10) {
	motion.y -= 10;
    }
    
    if(move_down && y < (HEIGHT-110)) {
	motion.y += 10;
    }

    var speed;
    // Magic computation to get speed from Rudolph's position on screen
    speed = (320 - rudolph.pos.x + 50) / 30 - 2;
    if(speed < 0) {
	speed = 0;
    }
    speed = Math.round(speed);

    while(snowflakes.length < NUM_SNOWFLAKES) {
	var sfpos = vec(0, 0);

	if(randint(2)) {
	    // Start along top edge
	    sfpos.x = randint(WIDTH);
	    sfpos.y = -10;
	} else {
	    // Start along left edge
	    sfpos.x = -10;
	    sfpos.y = randint(HEIGHT);
	}

	snowflakes.push(new Sprite(sfpos, vec(0, randrange(1, 5)), 'snowflake'));
    }

    if(move_drop && santa.image == 'santa1' ) {
	play_sound('whistle');
	gifts.push(new Gift(vec(santa.pos.x+35, santa.pos.y+30), vec(-speed, 0), 'gift'));
	santa.image = 'santa2';
	timer.after(20, function() { santa.image = 'santa3'; });
	timer.after(30, function() { santa.image = 'santa1'; });
    }

    for(var i = 0; i < houses.length; i++) {
	houses[i].move(speed);
    }
    for(var i = 0; i < gifts.length; i++) {
	gifts[i].move(speed);
    }
    for(var i = 0; i < things.length; i++) {
	things[i].move(speed);
    }
    for(var i = 0; i < snowflakes.length; i++) {
	snowflakes[i].move(speed);
    }

    var outside = function(obj) {
	// True if obj is outside the screen
	return obj.pos.x + obj.image.width < 0 || obj.pos.x >= WIDTH ||
	obj.pos.y + obj.image.height < 0 || obj.pos.y >= HEIGHT;
    };

    removeif(things, outside);
    removeif(snowflakes, outside);
    removeif(houses,
   	     function(obj) {
    		 return obj.pos.x >= WIDTH;
    	     });

    next_house_in -= speed;
    if(next_house_in <= 0) {
	var house = new House(vec(-images['chimney'].width, 440), vec(0, 0), 'chimney');
	houses.push(house);
	
	next_house_in = randrange(200, 400);
    }

    removeif(gifts,
	     function(gift) {
		 if(gift.pos.y > HEIGHT || gift.pos.x > WIDTH) {
		     return true;
		 }

		 var remove = false;

		 // Hit?
		 for(var i = 0; i < houses.length; i++) {
		     var house = houses[i];

		     // Test upper/left corner against a box
		     var x1 = house.pos.x + 25;
		     var x2 = x1 + 35;
		     var y1 = house.pos.y - 20;
		     var y2 = y1 + 50;

		     // ctx.fillStyle = 'rgb(255, 255, 255)';
		     // ctx.fillRect(x1, y1, x2-x1+images.gift.width, y2-y1+images.gift.height);
		     
		     if(gift.pos.x >= x1 &&
			gift.pos.x <= x2 &&
			gift.pos.y >= y1 &&
			gift.pos.y <= y2 &&
			true) {

			 var image;
			 if(house.smoking) {
			     play_sound('poof');
			     image = 'poof';
			 } else {
			     play_sound('plingeling');
			     image = 'star';
			 }
			 things.push(new Sprite(vec(house.pos.x+35, house.pos.y-10), vec(0, -6), image));
			 return true;
		     }
		 }

		 // Splat
		 for(var i = 0; i < houses.length; i++) {
		     var house = houses[i];
		     if(gift.pos.y >= HEIGHT - 35
			// + 10 / -10 here to allow sit partly on roof
			&& gift.pos.x + 10 >= house.pos.x
			&& (gift.pos.x - 10 + images['gift'].width) <= (house.pos.x + images['chimney'].width)
			)
			 {
			     play_sound('splat');
			     things.push(new Sprite(gift.pos, vec(0, 0), 'splat'));
			     return true;
			 }
		 } 

		 return false;
	     });



    // xc = constrain(rudolph.pos.x + motion.x, 10, WIDTH-340);
    // yc = constrain(rudolph.pos.y + motion.y, 10, HEIGHT-110);

    rudolph.pos.add(motion);
    timer.after(3, function() { reindeer.pos.add(motion) });
    timer.after(6, function() { santa.pos.add(motion) });

    if(deer > 20) {
	if(frame == 1) {
	    frame = 2;
	} else {
	    frame = 1;
	}
	deer = 0;
    }
    deer += 1;

    //
    // Draw
    //

    rudolph.image = 'rudolph' + frame;
    reindeer.image = 'reindeer' + frame;
    
    for(var i=0; i < snowflakes.length; i++) {
	snowflakes[i].draw();
    }
    for(var i = 0; i < houses.length; i++) {
	var house = houses[i];
	houses[i].draw();

	if(house.smoking) {
	    ctx.drawImage(images['smoke'+frame], house.pos.x+42, house.pos.y-36);
	}
    }

    ctx.strokeStyle = "#000";
    ctx.beginPath();
    ctx.moveTo(rudolph.pos.x+30, rudolph.pos.y+40);
    ctx.lineTo(reindeer.pos.x+30, reindeer.pos.y+40);
    ctx.lineTo(santa.pos.x+2, santa.pos.y+62);
    // ctx.closePath();
    ctx.stroke();

    rudolph.draw();
    reindeer.draw();
    santa.draw();

    for(var i=0; i < gifts.length; i++) {
	gifts[i].draw();
    }
    for(var i=0; i < things.length; i++) {
	things[i].draw();
    }
}

function keyhandler(event)
{
    var value;

    if(event.type == "keydown") {
	value = true;
    } else {
	value = false;
    }

    switch(event.keyCode) {
    case 38:
	move_up = value;
	break;
    case 40:
	move_down = value;
	break;
    case 37:
	move_left = value;
	break;
    case 39:
	move_right = value;
	break;
    case 32:
	move_drop = value;
	break;
    }
}

function init()
{
    canvas = document.getElementById("canvas");
    ctx = canvas.getContext("2d");

    document.addEventListener('keydown', keyhandler, false);
    document.addEventListener('keyup', keyhandler, false);

    WIDTH = canvas.width;
    HEIGHT = canvas.height;

    

    load_data(onload=animate);
}

init();