Wytłuszczyłem miejsca które wymagały modyfikacji:
// Create the canvas
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
canvas.width = 512;
canvas.height = 480;
document.body.appendChild(canvas);
// Background image
var bgReady = false;
var bgImage = new Image();
bgImage.onload = function () {
bgReady = true;
};
bgImage.src = "images/background.png";
// Hero image
var heroReady = false;
var heroImage = new Image();
heroImage.onload = function () {
heroReady = true;
};
heroImage.src = "images/hero.png";
// Monster image
var monsterReady = false;
var monsterImage = new Image();
monsterImage.onload = function () {
monsterReady = true;
};
monsterImage.src = "images/monster.png";
// Game objects
var hero = {
speed: 256 // movement in pixels per second
};
var monster = [];
var monstersCaught = 0;
// Handle keyboard controls
var keysDown = {};
addEventListener("keydown", function (e) {
keysDown[e.keyCode] = true;
}, false);
addEventListener("keyup", function (e) {
delete keysDown[e.keyCode];
}, false);
// Reset the game when the player catches a monster
var reset = function (monsterNumber) {
hero.x = canvas.width / 2;
hero.y = canvas.height / 2;
// Throw the monster somewhere on the screen randomly
** if(monsterNumber == null)**
** { for(var i = 0; i < 3; i++)**
** {**
** var x = 32 + (Math.random() * (canvas.width - 64));**
** var y = 32 + (Math.random() * (canvas.height - 64));**
** monster.push({x: x, y: y});**
** }**
** }**
** else**
** {**
var x = 32 + (Math.random() * (canvas.width - 64));
** var y = 32 + (Math.random() * (canvas.height - 64));**
** monster[monsterNumber].x = x;**
** monster[monsterNumber].y = y;**
** }**
};
// Update game objects
var update = function (modifier) {
if (38 in keysDown) { // Player holding up
hero.y -= hero.speed * modifier;
}
if (40 in keysDown) { // Player holding down
hero.y += hero.speed * modifier;
}
if (37 in keysDown) { // Player holding left
hero.x -= hero.speed * modifier;
}
if (39 in keysDown) { // Player holding right
hero.x += hero.speed * modifier;
}
// Are they touching?
** for(var i = 0; i < 3; i++)**
** { **
** if (**
** hero.x <= (monster[i].x + 32)**
&& monster[i].x <= (hero.x + 32)
** && hero.y <= (monster[i].y + 32)**
** && monster[i].y <= (hero.y + 32)**
** ) {**
** ++monstersCaught;**
** reset(i);**
** }**
** }**
};
// Draw everything
var render = function () {
if (bgReady) {
ctx.drawImage(bgImage, 0, 0);
}
if (heroReady) {
ctx.drawImage(heroImage, hero.x, hero.y);
}
** if (monsterReady) {**
** * for(var i = 0; i < 3; i++)***
** ctx.drawImage(monsterImage, monster[i].x, monster[i].y);**
** }**
// Score
ctx.fillStyle = "rgb(250, 250, 250)";
ctx.font = "24px Helvetica";
ctx.textAlign = "left";
ctx.textBaseline = "top";
ctx.fillText("Goblins caught: " + monstersCaught, 32, 32);
};
// The main game loop
var main = function () {
var now = Date.now();
var delta = now - then;
update(delta / 1000);
render();
then = now;
// Request to do this again ASAP
requestAnimationFrame(main);
};
// Cross-browser support for requestAnimationFrame
var w = window;
requestAnimationFrame = w.requestAnimationFrame || w.webkitRequestAnimationFrame || w.msRequestAnimationFrame || w.mozRequestAnimationFrame;
// Let's play this game!
var then = Date.now();
reset();
main();