JAVASCRIPT
window.addEventListener("load",function() {
//constants
var GAME_WIDTH = 640;
var GAME_HEIGHT = 360;
//keep the game going
var gameLive = true;
//current level
var level = 1;
var life = 5;
//random color
var color = "#"+((1<<24)*Math.random()|0).toString(16);
//enemies
var enemies = [
{
x: 100, //x coordinate
y: 100, //y coordinate
speedY: 2, //speed in Y
w: 40, //width
h: 40 //heght
},
{
x: 200,
y: 0,
speedY: 2,
w: 40,
h: 40
},
{
x: 330,
y: 100,
speedY: 3,
w: 40,
h: 40
},
{
x: 450,
y: 100,
speedY: -3,
w: 40,
h: 40
}
];
//the player object
var player = {
x: 10,
y: 160,
speedX: 2,
isMoving: false, //keep track whether the player is moving or not
w: 40,
h: 40
};
//the goal object
var goal = {
x: 580,
y: 160,
w: 50,
h: 36
}
var sprites = {};
var movePlayer = function() {
player.isMoving = true;
}
var stopPlayer = function() {
player.isMoving = false;
}
//grab the canvas and context
var canvas = document.getElementById("mycanvas");
var ctx = canvas.getContext("2d");
//event listeners to move player
canvas.addEventListener('mousedown', movePlayer);
canvas.addEventListener('mouseup', stopPlayer);
canvas.addEventListener('touchstart', movePlayer);
canvas.addEventListener('touchend', stopPlayer);
//update the logic
var update = function() {
//check if you've won the game
if(checkCollision(player, goal)) {
alert('Win !');
level += 1;
life += 1;
player.speedX += 1;
player.x = 10;
player.y = 160;
player.isMoving = false;
for(var ab = 0; ab < enemies.length; ab++){
if(enemies[ab].speedY > 1){
enemies[ab].speedY += 1 ;
}
else{
enemies[ab].speedY -= 1 ;
}
}
}
//update player
if(player.isMoving) {
player.x = player.x + player.speedX;
}
//update enemies
var i = 0;
var n = enemies.length;
enemies.forEach(function(element, index){
//check for collision with player
if(checkCollision(player, element)) {
//stop the game
if(life === 0){
alert('Game Over');
for(var ab = 0; ab < enemies.length; ab++){
if(enemies[ab].speedY > 1){
enemies[ab].speedY -= (level - 1) ;
}
else{
enemies[ab].speedY += (level - 1) ;
}
}
level = 1;
life = 6;
player.speedX = 2;
color ="#"+((1<<24)*Math.random()|0).toString(16);
}
if(life > 0){
life -= 1 ;
color ="#"+((1<<24)*Math.random()|0).toString(16);
}
player.x = 10;
player.y = 160;
player.isMoving = false;
}
//move enemy
element.y += element.speedY;
//check borders
if(element.y <= 10) {
element.y = 10;
//element.speedY = element.speedY * -1;
element.speedY *= -1;
}
else if(element.y >= GAME_HEIGHT - 50) {
element.y = GAME_HEIGHT - 50;
element.speedY *= -1;
}
});
};
//show the game on the screen
var draw = function() {
//clear the canvas
ctx.clearRect(0,0,GAME_WIDTH,GAME_HEIGHT);
//draw level
ctx.font = "15px Verdana";
ctx.fillStyle = "rgb(0,0,0)";
ctx.fillText("Level : " + level , 10, 15);
ctx.fillText("Lives : " + life , 10, 35);
ctx.fillText("Level of Speed : " + player.speedX , 10, 55,);
//draw player with random color
ctx.fillStyle = color;
ctx.fillRect(player.x, player.y, player.w, player.h);
//draw enemies
ctx.fillStyle = "rgb(255,120,70)";
enemies.forEach(function(element, index){
ctx.fillRect(element.x, element.y, element.w, element.h);
});
//draw goal
ctx.fillStyle = "rgb(0,255,120)";
ctx.fillRect(goal.x, goal.y, goal.w, goal.h);
ctx.fillStyle = "rgb(0,0,0)";
ctx.fillText("Goal", goal.x + 7, goal.y + 25);
};
//gets executed multiple times per second
var step = function() {
update();
draw();
if(gameLive) {
window.requestAnimationFrame(step);
}
};
//check the collision between two rectangles
var checkCollision = function(rect1, rect2) {
var closeOnWidth = Math.abs(rect1.x - rect2.x) <= Math.max(rect1.w, rect2.w);
var closeOnHeight = Math.abs(rect1.y - rect2.y) <= Math.max(rect1.h, rect2.h);
return closeOnWidth && closeOnHeight;
}
//initial kick
step();
});
