Hi everyone,
everything works fine with my code, except the evil.collisionDetect function.
When a ball touch the evil nothing happend.
Pease find my code below, any help or suggestion will be welcome!!
I spent the whole last night to try to find my error…unsuccessfull!!
(sorry for my english).
My code :
// setup canvas
var canvas = document.querySelector(‘canvas’);
var ctx = canvas.getContext(‘2d’);
var width = canvas.width = window.innerWidth;
var height = canvas.height = window.innerHeight;
var compteur = document.querySelector (‘p’);
var count = 0;
// function to generate random number
function random(min,max) {
var num = Math.floor(Math.random()*(max+1-min)) + min;
return num;
}
function Shape(x, y, velX, velY, exists){
this.x = x;
this.y = y;
this.velX = velX;
this.velY = velY;
this.exists = exists;
}
function Ball(x, y, velX, velY, exists, color, size){
Shape.call(this, x, y, velX, velY, exists);
this.color = color;
this.size = size;
}
Ball.prototype = Object.create(Shape.prototype);
Ball.prototype.constructor = Ball;
function EvilCircle(x, y, exists){
Shape.call(this, x, y, 20, 20, exists);
this.color = ‘white’;
this.size = 10;
}
EvilCircle.prototype = Object.create(Shape.prototype);
EvilCircle.prototype.constructor = EvilCircle;
Ball.prototype.draw = function() {
ctx.beginPath();
ctx.fillStyle = this.color;
ctx.arc(this.x, this.y, this.size, 0, 2 * Math.PI);
ctx.fill();
}
Ball.prototype.update = function() {
if ((this.x + this.size) >= width){
this.velX = -(this.velX);
}
if ((this.x - this.size) <= 0){
this.velX = -(this.velX);
}
if ((this.y + this.size) >= height) {
this.velY = -(this.velY);
}
if ((this.y - this.size) <= 0) {
this.velY = -(this.velY);
}
this.x += this.velX;
this.y += this.velY;
}
EvilCircle.prototype.checkBounds = function() {
if ((this.x + this.size) >= width){
this.x = (width - this.size);
}
if ((this.x - this.size) <= 0){
this.x = this.size;
}
if ((this.y + this.size) >= height) {
this.y = (height - this.size);
}
if ((this.y - this.size) <= 0) {
this.y = this.size;
}
}
EvilCircle.prototype.setControls = function() {
var _this = this;
window.onkeydown = function(e) {
if (e.keyCode === 37) {
_this.x -= _this.velX;
} else if (e.keyCode === 39) {
_this.x += _this.velX;
} else if (e.keyCode === 38) {
_this.y -= _this.velY;
} else if (e.keyCode === 40) {
_this.y += _this.velY;
}
}
}
Ball.prototype.collisionDetect = function() {
for (var j = 0; j < balls.length; j++) {
if (!(this === balls[j])) {
var dx = this.x - balls[j].x;
var dy = this.y - balls[j].y;
var distance = Math.sqrt(dx * dx + dy * dy);
if (distance < this.size + balls[j].size) {
balls[j].color = this.color = 'rgb(' + random(0, 255) + ',' + random(0, 255) + ',' + random(0, 255) +')';
}
}
}
};
EvilCircle.prototype.collisionDetect = function() {
for (var j = 0; j < balls.length; j++) {
if (balls[j].exists = true) {
var dx = this.x - balls[j].x;
var dy = this.y - balls[j].y;
var distance = Math.sqrt(dx * dx + dy * dy);
if (distance < this.size + balls[j].size) {
balls[j].exists = false;
count--;
}
}
}
};
EvilCircle.prototype.draw = function() {
ctx.beginPath();
ctx.lineWidth = 3;
ctx.strokeStyle = this.color;
ctx.arc(this.x, this.y, this.size, 0, 2 * Math.PI);
ctx.stroke();
};
var balls = [];
var viseur = new EvilCircle(
random(0,width),
random(0,height),
20,
20,
true);
viseur.setControls();
function loop() {
ctx.fillStyle = ‘rgba(0, 0, 0, 0.5)’;
ctx.fillRect(0, 0, width, height);
while (balls.length < 15) {
var ball = new Ball(
random(0,width),
random(0,height),
random(-7,7),
random(-7,7),
true,
‘rgb(’ + random(0,255) + ‘,’ + random(0,255) + ‘,’ + random(0,255) +’)’,
random(10,20)
);
balls.push(ball);
count++;
};
viseur.draw();
viseur.collisionDetect();
viseur.checkBounds();
for (var i = 0; i < balls.length; i++) {
if (balls[i].exists = true){
balls[i].draw();
balls[i].update();
balls[i].collisionDetect();
}
}
requestAnimationFrame(loop);
}
loop();
compteur.textContent += (count);
