Develop Reference

want to style the all dots of pre built html canvas background

The code is different, I apologize may I didn't ask the question the right way, you can understand well in principle, When I'm hovering the dots get colours and connect to each other, other dots are invisible, I want that all dots should be visible all time. live example available on codepen, https://codepen.io/tati420/pen/RwBamQo?editors=1111
(function () {
var width,
height,
largeHeader,
canvas,
ctx,
points,
target,
animateHeader = true;
// Main
initHeader();
initAnimation();
addListeners();
function initHeader() {
width = window.innerWidth;
height = window.innerHeight;
target = { x: width / 2, y: height / 2 };
largeHeader = document.getElementById("large-header");
largeHeader.style.height = height + "px";
canvas = document.getElementById("demo-canvas");
canvas.width = width;
canvas.height = height;
ctx = canvas.getContext("2d");
// create points
points = [];
for (var x = 0; x < width; x = x + width / 20) {
for (var y = 0; y < height; y = y + height / 20) {
var px = x + (Math.random() * width) / 20;
var py = y + (Math.random() * height) / 20;
var p = { x: px, originX: px, y: py, originY: py };
points.push(p);
}
}
// for each point find the 5 closest points
for (var i = 0; i < points.length; i++) {
var closest = [];
var p1 = points[i];
for (var j = 0; j < points.length; j++) {
var p2 = points[j];
if (!(p1 == p2)) {
var placed = false;
for (var k = 0; k < 5; k++) {
if (!placed) {
if (closest[k] == undefined) {
closest[k] = p2;
placed = true;
}
}
}
for (var k = 0; k < 5; k++) {
if (!placed) {
if (getDistance(p1, p2) < getDistance(p1, closest[k])) {
closest[k] = p2;
placed = true;
}
}
}
}
}
p1.closest = closest;
}
// assign a circle to each point
for (var i in points) {
var c = new Circle(
points[i],
2 + Math.random() * 2,
"rgba(0,255,255,0.3)"
);
points[i].circle = c;
}
}
// Event handling
function addListeners() {
if (!("ontouchstart" in window)) {
window.addEventListener("mousemove", mouseMove);
}
window.addEventListener("scroll", scrollCheck);
window.addEventListener("resize", resize);
}
function mouseMove(e) {
var posx = (posy = 0);
if (e.pageX || e.pageY) {
posx = e.pageX;
posy = e.pageY;
} else if (e.clientX || e.clientY) {
posx =
e.clientX +
document.body.scrollLeft +
document.documentElement.scrollLeft;
posy =
e.clientY +
document.body.scrollTop +
document.documentElement.scrollTop;
}
target.x = posx;
target.y = posy;
}
function scrollCheck() {
if (document.body.scrollTop > height) animateHeader = false;
else animateHeader = true;
}
function resize() {
width = window.innerWidth;
height = window.innerHeight;
largeHeader.style.height = height + "px";
canvas.width = width;
canvas.height = height;
}
// animation
function initAnimation() {
animate();
for (var i in points) {
shiftPoint(points[i]);
}
}
function animate() {
if (animateHeader) {
ctx.clearRect(0, 0, width, height);
for (var i in points) {
// detect points in range
if (Math.abs(getDistance(target, points[i])) < 4000) {
points[i].active = 0.3;
points[i].circle.active = 0.6;
} else if (Math.abs(getDistance(target, points[i])) < 20000) {
points[i].active = 0.1;
points[i].circle.active = 0.3;
} else if (Math.abs(getDistance(target, points[i])) < 40000) {
points[i].active = 0.02;
points[i].circle.active = 0.1;
} else {
points[i].active = 0;
points[i].circle.active = 0;
}
drawLines(points[i]);
points[i].circle.draw();
}
}
requestAnimationFrame(animate);
}
function shiftPoint(p) {
TweenLite.to(p, 1 + 1 * Math.random(), {
x: p.originX - 50 + Math.random() * 100,
y: p.originY - 50 + Math.random() * 100,
ease: Circ.easeInOut,
onComplete: function () {
shiftPoint(p);
},
});
}
ctx.strokeStyle = "rgba(255,0,0," + p.active + ")";
// Canvas manipulation
function drawLines(p) {
if (!p.active) return;
for (var i in p.closest) {
ctx.beginPath();
ctx.moveTo(p.x, p.y);
ctx.lineTo(p.closest[i].x, p.closest[i].y);
ctx.strokeStyle = "rgba(0,255,255," + p.active + ")";
ctx.stroke();
}
}
function Circle(pos, rad, color) {
var _this = this;
// constructor
(function () {
_this.pos = pos || null;
_this.radius = rad || null;
_this.color = color || null;
})();
this.draw = function () {
if (!_this.active) return;
ctx.beginPath();
ctx.arc(_this.pos.x, _this.pos.y, _this.radius, 0, 2 * Math.PI, false);
ctx.fillStyle = "rgba(0,255,0," + _this.active + ")";
ctx.fill();
};
}
// Util
function getDistance(p1, p2) {
return Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2);
}
})();

If I understand your question correctly, you just want to make sure that every point.active = 1 and point.circle.active = 1:
function animate() {
if (animateHeader) {
ctx.clearRect(0, 0, width, height);
for (var i in points) {
points[i].active = 1;
points[i].circle.active = 1;
drawLines(points[i]);
points[i].circle.draw();
}
}
requestAnimationFrame(animate);
}

How do i move the "interaction" with the "blob" in this animated blob?

I downloaded this javascript blob graphic, I've added it to my page, and moved it to the right using CSS, But when I move the mouse to interact with the blob, it still thinks the blob is in the middle of the screen. How do I move the interaction to the right with the blob?
let canvas, ctx;
let render, init;
let blob;
class Blob {
constructor() {
this.points = [];
}
init() {
for (let i = 0; i < this.numPoints; i++) {
let point = new Point(this.divisional * (i + 1), this);
// point.acceleration = -1 + Math.random() * 2;
this.push(point);
}
}
render() {
let canvas = this.canvas;
let ctx = this.ctx;
let position = this.position;
let pointsArray = this.points;
let radius = this.radius;
let points = this.numPoints;
let divisional = this.divisional;
let center = this.center;
ctx.clearRect(0, 0, canvas.width, canvas.height);
pointsArray[0].solveWith(pointsArray[points - 1], pointsArray[1]);
let p0 = pointsArray[points - 1].position;
let p1 = pointsArray[0].position;
let _p2 = p1;
ctx.beginPath();
ctx.moveTo(center.x, center.y);
ctx.moveTo((p0.x + p1.x) / 2, (p0.y + p1.y) / 2);
for (let i = 1; i < points; i++) {
pointsArray[i].solveWith(pointsArray[i - 1], pointsArray[i + 1] || pointsArray[0]);
let p2 = pointsArray[i].position;
var xc = (p1.x + p2.x) / 2;
var yc = (p1.y + p2.y) / 2;
ctx.quadraticCurveTo(p1.x, p1.y, xc, yc);
// ctx.lineTo(p2.x, p2.y);
ctx.fillStyle = '#000000';
// ctx.fillRect(p1.x-2.5, p1.y-2.5, 5, 5);
p1 = p2;
}
var xc = (p1.x + _p2.x) / 2;
var yc = (p1.y + _p2.y) / 2;
ctx.quadraticCurveTo(p1.x, p1.y, xc, yc);
// ctx.lineTo(_p2.x, _p2.y);
// ctx.closePath();
ctx.fillStyle = this.color;
ctx.fill();
ctx.strokeStyle = '#000000';
// ctx.stroke();
/*
ctx.fillStyle = '#000000';
if(this.mousePos) {
let angle = Math.atan2(this.mousePos.y, this.mousePos.x) + Math.PI;
ctx.fillRect(center.x + Math.cos(angle) * this.radius, center.y + Math.sin(angle) * this.radius, 5, 5);
}
*/
requestAnimationFrame(this.render.bind(this));
}
push(item) {
if (item instanceof Point) {
this.points.push(item);
}
}
set color(value) {
this._color = value;
}
get color() {
return this._color || '#000000';
}
set canvas(value) {
if (value instanceof HTMLElement && value.tagName.toLowerCase() === 'canvas') {
this._canvas = canvas;
this.ctx = this._canvas.getContext('2d');
}
}
get canvas() {
return this._canvas;
}
set numPoints(value) {
if (value > 2) {
this._points = value;
}
}
get numPoints() {
return this._points || 32;
}
set radius(value) {
if (value > 0) {
this._radius = value;
}
}
get radius() {
return this._radius || 150;
}
set position(value) {
if (typeof value == 'object' && value.x && value.y) {
this._position = value;
}
}
get position() {
return this._position || { x: 0.5, y: 0.5 };
}
get divisional() {
return Math.PI * 2 / this.numPoints;
}
get center() {
return { x: this.canvas.width * this.position.x, y: this.canvas.height * this.position.y };
}
set running(value) {
this._running = value === true;
}
get running() {
return this.running !== false;
}}
class Point {
constructor(azimuth, parent) {
this.parent = parent;
this.azimuth = Math.PI - azimuth;
this._components = {
x: Math.cos(this.azimuth),
y: Math.sin(this.azimuth) };
this.acceleration = -0.3 + Math.random() * 0.6;
}
solveWith(leftPoint, rightPoint) {
this.acceleration = (-0.3 * this.radialEffect + (leftPoint.radialEffect - this.radialEffect) + (rightPoint.radialEffect - this.radialEffect)) * this.elasticity - this.speed * this.friction;
}
set acceleration(value) {
if (typeof value == 'number') {
this._acceleration = value;
this.speed += this._acceleration * 2;
}
}
get acceleration() {
return this._acceleration || 0;
}
set speed(value) {
if (typeof value == 'number') {
this._speed = value;
this.radialEffect += this._speed * 5;
}
}
get speed() {
return this._speed || 0;
}
set radialEffect(value) {
if (typeof value == 'number') {
this._radialEffect = value;
}
}
get radialEffect() {
return this._radialEffect || 0;
}
get position() {
return {
x: this.parent.center.x + this.components.x * (this.parent.radius + this.radialEffect),
y: this.parent.center.y + this.components.y * (this.parent.radius + this.radialEffect) };
}
get components() {
return this._components;
}
set elasticity(value) {
if (typeof value === 'number') {
this._elasticity = value;
}
}
get elasticity() {
return this._elasticity || 0.001;
}
set friction(value) {
if (typeof value === 'number') {
this._friction = value;
}
}
get friction() {
return this._friction || 0.0085;
}}
blob = new Blob();
init = function () {
canvas = document.getElementById('canvas');
canvas.setAttribute('touch-action', 'none');
let resize = function () {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
};
window.addEventListener('resize', resize);
resize();
let oldMousePoint = { x: 0, y: 0 };
let hover = false;
let mouseMove = function (e) {
let pos = blob.center;
let diff = { x: e.clientX - pos.x, y: e.clientY - pos.y };
let dist = Math.sqrt(diff.x * diff.x + diff.y * diff.y);
let angle = null;
blob.mousePos = { x: pos.x - e.clientX, y: pos.y - e.clientY };
if (dist < blob.radius && hover === false) {
let vector = { x: e.clientX - pos.x, y: e.clientY - pos.y };
angle = Math.atan2(vector.y, vector.x);
hover = true;
// blob.color = '#77FF00';
} else if (dist > blob.radius && hover === true) {
let vector = { x: e.clientX - pos.x, y: e.clientY - pos.y };
angle = Math.atan2(vector.y, vector.x);
hover = false;
blob.color = null;
}
if (typeof angle == 'number') {
let nearestPoint = null;
let distanceFromPoint = 100;
blob.points.forEach(point => {
if (Math.abs(angle - point.azimuth) < distanceFromPoint) {
// console.log(point.azimuth, angle, distanceFromPoint);
nearestPoint = point;
distanceFromPoint = Math.abs(angle - point.azimuth);
}
});
if (nearestPoint) {
let strength = { x: oldMousePoint.x - e.clientX, y: oldMousePoint.y - e.clientY };
strength = Math.sqrt(strength.x * strength.x + strength.y * strength.y) * 10;
if (strength > 100) strength = 100;
nearestPoint.acceleration = strength / 100 * (hover ? -1 : 1);
}
}
oldMousePoint.x = e.clientX;
oldMousePoint.y = e.clientY;
};
// window.addEventListener('mousemove', mouseMove);
window.addEventListener('pointermove', mouseMove);
blob.canvas = canvas;
blob.init();
blob.render();
};
window.addEventListener('DOMContentLoaded', () => {
init();
});
canvas {
position: absolute;
touch-action: none;
}
#canvarse {
padding-left: 800px;
}
<div id="canvarse">
<canvas id="canvas"></canvas>
<!-- partial:index.partial.html -->
<script src="https://code.jquery.com/pep/0.4.3/pep.js"></script>
<!-- partial -->
<script src="js/script.js"></script>
</div>
If you run the code snippet, you can see that the blob still thinks its in the middle of the canvas when it's actually where its supposed to be on the right.
I'm struggling to see how I can move the interaction across with the blob?
Anyone help?

seems like it was pretty easy you just have to play with the position function in your JavaScript, First remove your CSS completely because it is unnecessary and find this particular line on your JavaScript and change the X axis position if you want to move the blob horizontally and Y axis if you want vertical movement
get position() {
return this._position || { x: 0.8, y: 0.5 };
}
by default it was x:0.5 which means center so I changed it to 0.8 slight movement towards right side. hope this helps

Canvas particle animation mobile touch event with elements positioned on top

I have this canvas particle animation that follows the mouse event correctly but it does not follow a touch event on mobile. I realized that it's because I have this animation beneath the rest of the content which is positioned on top. When there is something on top of the canvas that it's hitting, it does not trigger the touch event. I'm hoping someone can help me figure out how to avoid this issue so that the animation will still follow the user underneath the page content.
JS
var PI2 = Math.PI * 2;
var HALF_PI = Math.PI / 2;
var isTouch = 'ontouchstart' in window;
var isSafari = !!navigator.userAgent.match(/Version\/[\d\.]+.*Safari/);
function Canvas(options) {
options = _.clone(options || {});
this.options = _.defaults(options, this.options);
this.el = this.options.el;
this.ctx = this.el.getContext('2d');
this.dpr = window.devicePixelRatio || 1;
this.updateDimensions();
window.addEventListener('resize', this.updateDimensions.bind(this), false);
this.resetTarget();
if(isTouch){
// touch
this.el.addEventListener('touchstart', this.touchMove.bind(this), false);
this.el.addEventListener('touchmove', this.touchMove.bind(this), false);
// this.el.addEventListener('touchend', this.resetTarget.bind(this), false);
} else {
// Mouse
window.addEventListener('mousemove', this.mouseMove.bind(this), false);
window.addEventListener('mouseout', this.resetTarget.bind(this), false);
}
this.setupParticles();
this.loop();
}
Canvas.prototype.updateDimensions = function() {
this.width = this.el.width = _.result(this.options, 'width') * this.dpr;
this.height = this.el.height = _.result(this.options, 'height') * this.dpr;
this.el.style.width = _.result(this.options, 'width') + 'px';
this.el.style.height = _.result(this.options, 'height') + 'px';
}
// Update the orb target
Canvas.prototype.mouseMove = function(event) {
this.target = new Vector(event.clientX * this.dpr, event.clientY* this.dpr);
}
// Reset to center when we mouse out
Canvas.prototype.resetTarget = function() {
this.target = new Vector(this.width / 2, this.height /2);
}
// Touch Eent
Canvas.prototype.touchMove = function(event) {
if(event.touches.length === 1) { event.preventDefault(); }
this.target = new Vector(event.touches[0].pageX * this.dpr, event.touches[0].pageY * this.dpr);
}
// Defaults
Canvas.prototype.options = {
count: 11,
speed: 0.001,
width: 400,
height: 400,
size: 5,
radius: 1,
background: '240, 240, 240, 0.6',
maxDistance: 100
}
Canvas.prototype.setupParticles = function() {
this.particles = [];
var index = -1;
var between = PI2 / this.options.count;
while(++index < this.options.count) {
var x;
var y;
var angle;
var max = Math.max(this.width, this.height);
angle = (index + 1) * between;
x = Math.cos(angle) * max;
x += this.width / 2;
y = Math.sin(angle) * max;
y += this.height / 2;
var particle = new Particle({
x: x,
y: y,
radius: this.options.radius,
size: this.options.size,
angle: angle,
color: this.options.color
});
this.particles.push(particle);
}
}
Canvas.prototype.findClosest = function() {
var index = -1;
var pointsLength = this.particles.length;
while(++index < pointsLength) {
var closestIndex = -1;
this.particles[index].closest = [];
while(++closestIndex < pointsLength) {
var closest = this.particles[closestIndex];
var distance = this.particles[index].position.distanceTo(closest.position);
if(distance < this.options.maxDistance) {
var vector = new Vector(closest.position.x, closest.position.y);
vector.opacity = 1 - (distance / this.options.maxDistance);
vector.distance = distance;
this.particles[index].closest.push(vector);
}
}
}
}
Canvas.prototype.loop = function() {
// this.clear();
if(isTouch || isSafari) {
this.ghost();
} else {
this.ghostGradient();
}
if(this.options.maxDistance > 0) {
this.findClosest();
}
this.draw();
window.requestAnimationFrame(_.bind(this.loop, this));
}
Canvas.prototype.clear = function() {
this.ctx.clearRect(0, 0 , this.width, this.height);
}
Canvas.prototype.ghost = function() {
this.ctx.globalCompositeOperation = "source-over";
this.ctx.rect(0, 0 , this.width, this.height);
if(typeof this.options.background === 'string') {
this.ctx.fillStyle = "rgba(" + this.options.background + ")";
} else {
this.ctx.fillStyle = "rgba(" + this.options.background[0] + ")";
}
this.ctx.fill();
}
Canvas.prototype.ghostGradient = function() {
var gradient;
if(typeof this.options.background === 'string') {
this.ctx.fillStyle = 'rgba(' + this.options.background + ')';
} else {
var gradient = this.ctx.createLinearGradient(0, 0, 0, this.height);
var length = this.options.background.length;
for(var i = 0; i < length; i++){
gradient.addColorStop((i+1) / length, 'rgba(' + this.options.background[i] + ')');
}
this.ctx.fillStyle = gradient;
}
this.ctx.globalOpacity = 0.1;
this.ctx.globalCompositeOperation = "darken";
this.ctx.fillRect(0, 0 , this.width, this.height);
}
// Draw
Canvas.prototype.draw = function() {
var index = -1;
var length = this.particles.length;
while(++index < length) {
var point = this.particles[index];
var color = point.color || this.options.color;
point.update(this.target, index);
this.ctx.globalAlpha = 0.3;
this.ctx.globalCompositeOperation = "lighten";
this.ctx.fillStyle = 'rgb(' + color + ')';
this.ctx.beginPath();
this.ctx.arc(point.position.x, point.position.y, point.size, 0, PI2, false);
this.ctx.closePath();
this.ctx.fill();
if(this.options.maxDistance > 0) {
this.drawLines(point, color);
}
}
}
// Draw connecting lines
Canvas.prototype.drawLines = function (point, color) {
color = color || this.options.color;
var index = -1;
var length = point.closest.length;
this.ctx.globalAlpha = 0.2;
this.ctx.globalCompositeOperation = "screen";
this.ctx.lineCap = 'round';
while(++index < length) {
this.ctx.lineWidth = (point.size * 2) * point.closest[index].opacity;
this.ctx.strokeStyle = 'rgba(250,250,250, ' + point.closest[index].opacity + ')';
this.ctx.beginPath();
this.ctx.moveTo(point.position.x, point.position.y);
this.ctx.lineTo(point.closest[index].x, point.closest[index].y);
this.ctx.stroke();
}
}
function Particle(options) {
options = _.clone(options || {});
this.options = _.defaults(options, this.options);
this.position = this.shift = new Vector(this.options.x, this.options.y);
this.speed = this.options.speed || 0.01 + Math.random() * 0.04;
this.angle = this.options.angle || 0;
if(this.options.color) {
var color = this.options.color.split(',');
var colorIndex = -1;
while(++colorIndex < 3) {
color[colorIndex] = Math.round(parseInt(color[colorIndex], 10) + (Math.random()*100)-50);
// Clamp
color[colorIndex] = Math.min(color[colorIndex], 255);
color[colorIndex] = Math.max(color[colorIndex], 0);
}
this.color = color.join(', ');
}
// Size
this.options.size = this.options.size || 7;
this.size = 1 + Math.random() * this.options.size;
this.targetSize = this.options.targetSize || this.options.size;
this.orbit = this.options.radius * 0.5 + (this.options.radius * 0.5 * Math.random());
}
Particle.prototype.update = function(target, index) {
this.angle += this.speed;
this.shift.x += (target.x - this.shift.x) * this.speed;
this.shift.y += (target.y - this.shift.y) * this.speed;
this.position.x = this.shift.x + Math.cos(index + this.angle) * this.orbit;
this.position.y = this.shift.y + Math.sin(index + this.angle) * this.orbit;
if(!isSafari) {
this.size += (this.targetSize - this.size) * 0.03;
if(Math.round(this.size) === Math.round(this.targetSize)) {
this.targetSize = 1 + Math.random() * this.options.size;
}
}
}
function Vector(x, y) {
this.x = x || 0;
this.y = y || 0;
}
Vector.prototype.distanceTo = function(vector, abs) {
var distance = Math.sqrt(Math.pow(this.x - vector.x, 2) + Math.pow(this.y - vector.y, 2));
return abs || false ? Math.abs(distance) : distance;
};
new Canvas({
el: document.getElementById('canvas'),
count: 25,
speed: 0.3,
radius: 6,
width: function() { return window.innerWidth; },
height: function() { return window.innerHeight; },
size: 15,
color: '30, 180, 1',
maxDistance: 100,
background: ['250,250,250,1', '215,216,215,0.8']
})
CSS
html, body {
min-height: 100%;
height: 100%;
}
#canvas {
width: 100%;
height: 100%;
position: fixed;
z-index: 100;
}
.page-content {
position: relative;
z-index: 900;
display: flex;
flex-direction: column;
}
HTML
<body>
<div id="container">
<canvas id="canvas"></canvas>
<div class="page-content">
</div>
</div>
</body>

Why the nextButton/startButton does not work?

I am working on a project on Khan Academy in which I have to create a game with at least 3 levels. I have developed most of the game but when I tried to proceed from one level to next the game somehow stops.
Here is the full project:
Project Link
/**
* Contains 3 levels
*
*
* Changed Ground
* Brown rectangle is replaced with Dirt Block.
*
* Scoring system changed
* Collecting Good sticks gets 1 point.
* Collecting Bad sticks gets -1 point. (i.e. loses point).
* Hitting rocks will lose 1 point.
*
**/
var level = 0;
var nosOfSticks = 5;
var target = 0;
var speed = 1;
var endLevel = false;
var buttonClicked = false;
var levelButtonEnabled = false;
var startButtonEnabled = true;
var Beaver = function(x, y) { // Beaver Constructor
this.x = x;
this.y = y;
this.img = getImage("creatures/Hopper-Happy");
this.sticks = 0;
};
Beaver.prototype.draw = function() { // Draw function to draw beaver
fill(255, 0, 0);
this.x = constrain(this.x, 0, width-40);
this.y = constrain(this.y, 0, height-50);
image(this.img, this.x, this.y, 40, 40);
};
Beaver.prototype.hop = function() { // Hop function to make beaver hop
this.img = getImage("creatures/Hopper-Jumping");
this.y -= speed * 5;
};
Beaver.prototype.hopLeft = function() {
this.img = getImage("creatures/Hopper-Jumping");
this.x -= speed * 5;
};
Beaver.prototype.hopRight = function() {
this.img = getImage("creatures/Hopper-Jumping");
this.x += speed * 5;
};
Beaver.prototype.fall = function() { // fall function makes beaver fall on the ground
this.img = getImage("creatures/Hopper-Happy");
this.y += speed * 5;
};
Beaver.prototype.checkForStickGrab = function(stick) { // function that checks sticks grab
if ((stick.x >= this.x && stick.x <= (this.x + 40)) &&
(stick.y >= this.y && stick.y <= (this.y + 40))) {
stick.y = -400;
this.sticks++;
}
};
Beaver.prototype.checkForBadStickGrab = function(badstick) { // function that checks badsticks grab
if ((badstick.x >= this.x && badstick.x <= (this.x + 40)) &&
(badstick.y >= this.y && badstick.y <= (this.y + 40))) {
badstick.y = -400;
this.sticks--;
}
};
Beaver.prototype.checkForRockHit = function(rock) { // function that checks rocks hit
if ((rock.x >= this.x - 40 && rock.x <= (this.x + 40)) &&
(rock.y >= this.y - 30 && rock.y <= (this.y + 40))) {
rock.x = -400;
this.sticks--;
}
};
// Drawing Sticks
var Stick = function(x, y) { // Stick constructor
this.x = x;
this.y = y;
};
Stick.prototype.draw = function() { // Draw function to draw sticks
fill(0, 0, 0);
rectMode(CENTER);
rect(this.x, this.y, 5, 40);
};
var Badstick = function(x, y) { // Bad Sticks constructor
Stick.call(this, x, y);
};
//Badstick.prototype = Object.create(Stick);
Badstick.prototype.draw = function() { //Draw function to draw badsticks
fill(255, 0, 13);
rectMode(CENTER);
rect(this.x, this.y, 5, 40);
};
// Drawings Rocks
var Rock = function(x, y) { // rocks constructor
this.x = x;
this.y = y;
this.img = getImage("cute/Rock");
};
Rock.prototype.draw = function(x, y) { // function to draw rocks
fill(0, 0, 0);
image(this.img, this.x, this.y, 40, 40);
};
var beaver = new Beaver(200, 300);
var sticks = [];
for (var i = 0; i < nosOfSticks; i++) {
sticks.push(new Stick(i * 100 + 400, random(20, 260)));
}
var badSticks = [];
for (var i = 0; i < nosOfSticks/2; i++) {
badSticks.push(new Badstick(i * 200 + 400, random(20, 270)));
}
var rocks = [];
for ( var i = 0; i < nosOfSticks * 0.375; i++) {
rocks.push(new Rock(random(0, 375), i * random() - (i * 100)));
}
var grassXs = [];
for (var i = 0; i < 25; i++) {
grassXs.push(i*20);
}
var blockXs = [];
for (var i = 0; i < 25; i++) {
blockXs.push(i*20);
}
var Button = function (x, y, w, h, color, text, size, font, textcolor, best) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.color = color;
this.text = text;
this.size = size;
this.font = font;
this.textcolor = textcolor;
this.best = best;
};
Button.prototype.draw = function() {
rectMode(CORNER);
fill(this.color);
rect(this.x, this.y, this.w, this.h);
fill(this.textcolor);
stroke(this.textcolor);
textFont(this.font, this.size);
text(this.text, this.x + (this.w/2 - this.w/2.5), this.y + (this.h/2 + this.size/2.5));
/*textFont(this.font, this.size / 2);
text("Best : " + this.best, this.x + 10, this.y + 90);*/
};
Button.prototype.clicked = function() {
if(mouseIsPressed && mouseX >= this.x && mouseX <= this.x + this.w && mouseY >= this.y && mouseY <= this.y + this.h ) {
return true;
}
};
var nextButton = new Button(315, 360, 75, 30, color(0, 255, 0), "Next Level", 12, "Aerial Bold", color(0, 0, 0));
var startButton = new Button(315, 360, 75, 30, color(0, 255, 0), "Start Again", 12, "Aerial Bold", color(0, 0, 0));
var playButton = new Button(140, 250, 120, 50, color(0, 0, 0), "PLAY", 40, "Aerial Bold", color(255, 255, 255));
var level1Button = new Button(30, 120, 100, 100, color(0, 0, 0), "Level 1", 25, "Aerial Bold", color(255, 255, 255));
var level2Button = new Button(140, 120, 100, 100, color(0, 0, 0), "Level 2", 25, "Aerial Bold", color(255, 255, 255));
var level3Button = new Button(250, 120, 100, 100, color(0, 0, 0), "Level 3", 25, "Aerial Bold", color(255, 255, 255));
var drawWin = function() {
fill(255, 0, 0);
textSize(36);
text("YOU WIN!!!!", 100, 200);
nextButton.draw();
};
var drawLoss = function() {
fill(255, 0, 0);
textSize(36);
text("YOU LOSE!!!!", 100, 200);
startButton.draw();
};
var movement = function() {
if (keyIsPressed) {
if(keyCode === UP) {
beaver.hop();
} /*else if(keyCode === LEFT) {
beaver.hopLeft();
} else if(keyCode === RIGHT) {
beaver.hopRight();
} */
} else { beaver.fall();}
};
var drawScore = function() {
fill(0, 255, 0);
textSize(18);
text("Score: " + beaver.sticks, 10, 390);
};
var isWin = function() {
if(beaver.sticks >= target) {
drawWin();
speed = 1;
return true;
}
};
var isLoss = function() {
if (beaver.sticks < target ) {
speed = 1;
drawLoss();
return true;
}
};
var drawBackground = function() {
//static
speed = 1;
background(227, 254, 255);
stroke(0, 0, 0);
rectMode(CORNER);
rect(0, height*0.90, width, height*0.10);
for (var i = 0; i < grassXs.length; i++) {
image(getImage("cute/GrassBlock"), grassXs[i], height*0.85, 35, 20);
image(getImage("cute/DirtBlock"), grassXs[i], height*0.85, 35, 60);
grassXs[i] -= speed;
if (grassXs[i] <= - 20) {
grassXs[i] = width;
}
}
};
var drawSticks = function() {
for (var i = 0; i < sticks.length; i++) {
sticks[i].draw();
beaver.checkForStickGrab(sticks[i]);
sticks[i].x -= speed;
}
};
var drawBadSticks = function() {
for (var i = 0; i < badSticks.length; i++) {
badSticks[i].draw();
beaver.checkForBadStickGrab(badSticks[i]);
badSticks[i].x -= speed;
}
};
var drawRocks = function() {
for (var i = 0; i < rocks.length; i++) {
rocks[i].draw();
beaver.checkForRockHit(rocks[i]);
rocks[i].y += speed;
}
};
var drawLevel = function() {
speed = 1;
drawBackground();
if (level === 1) {
target = 1;
drawSticks();
}
if (level === 2) {
target = 1;
drawSticks();
drawBadSticks();
}
if (level === 3) {
target = 1;
drawBadSticks();
drawSticks();
drawRocks();
}
beaver.draw();
movement();
drawScore();
if (sticks[nosOfSticks - 1].x < -5) {
isWin();
isLoss();
}
};
var drawLevels = function() {
level = "l";
background(0, 0, 0);
level1Button.draw();
level2Button.draw();
level3Button.draw();
if (level1Button.clicked() && level === "l") {
level = 1;
drawLevel();
} else if (level2Button.clicked() && level === "l") {
level = 2;
drawLevel();
} else if (level3Button.clicked() && level === "l") {
level = 3;
drawLevel();
}
};
var drawStart = function() {
level = 0;
background(0);
text("Hoppy Beaver", 75, 50);
text("Extreme", 120, 100);
playButton.draw();
if (playButton.clicked() && level === 0) {
levelButtonEnabled = false;
drawLevels();
}
};
//drawStart();
mouseClicked = function() {
if (nextButton.clicked() || startButton.clicked()) {
if (beaver.sticks >= 1) {
if (level === 0) {
level = 1;
sticks = [];
draw();
isWin = false;
}
if (level === 1) {
level = 2;
sticks = [];
draw();
isWin = false;
}
if (level === 2) {
level = 3;
sticks = [];
draw();
isWin = false;
}
if (level === 3) {
level = 1;
sticks = [];
isWin = false;
draw();
}
} else if (beaver.sticks < 1) {
if (level === 1) {
level = 1;
sticks = [];
drawLevel();
isLoss = false;
}
if (level === 2) {
level = 2;
sticks = [];
drawLevel();
isLoss = false;
}
if (level === 3) {
level = 3;
sticks = [];
drawLevel();
isLoss = false;
}
}
}
};
draw = function() {
speed = 1;
if (level === 1) {
drawLevel();
} else if (level === 2) {
drawLevel();
} else if (level === 3) {
drawLevel();
} else if (level === "l") {
drawLevels();
} else { drawStart(); }
};

welcome to stackoverflow. The problem with your code is this bit right here in the drawLevel function.
if (sticks[nosOfSticks - 1].x < -5) {
isWin();
isLoss();
}
At the start of your program you initialize the sticks array with some stick objects in line 124. When level 1 ends and the next button is clicked, you set the sticks array to an empty array sticks=[] in the mouseClicked function.However, you never re-add anything into the sticks array. Thus, when that block of code runs, the element at position nosOfSticks-1 is undefined, leading to your problem.My suggestion is to make a for loop after sticks=[] to refill the sticks array just like in line 124.
Good Luck!
Also, take a look at this guide for debugging help, how to debug small programs.

Delete or hide the image in previous frame - html 5 canvas

I'm trying to edit a pacman implementation (source) using htlm5 and js. The problem is when I make the background transparent, the ghosts and pacman images holding the previews frames. This is an example about my problem.
My js code:
Pacman.FPS = 30;
Pacman.Ghost = function (game, map, colour) {
function getColour() {
if (eatable) {
if (secondsAgo(eatable) > 5) {
return game.getTick() % 20 > 10 ? "rgba(0, 0, 0, 0.1)" : "rgba(0, 0, 0, 0.1)";
} else {
return "rgba(0, 0, 0, 0.1)";
}
} else if(eaten) {
return "#222";
}
return colour;
};
function draw(ctx) {
var s = map.blockSize,
top = (position.y/10) * s,
left = (position.x/10) * s;
if (eatable && secondsAgo(eatable) > 8) {
eatable = null;
}
if (eaten && secondsAgo(eaten) > 3) {
eaten = null;
}
var tl = left + s;
var base = top + s - 3;
var inc = s / 10;
var high = game.getTick() % 10 > 5 ? 3 : -3;
var low = game.getTick() % 10 > 5 ? -3 : 3;
ctx.fillStyle = getColour();
ctx.beginPath();
ctx.moveTo(left, base);
ctx.quadraticCurveTo(left, top, left + (s/2), top);
ctx.quadraticCurveTo(left + s, top, left+s, base);
// Wavy things at the bottom
ctx.quadraticCurveTo(tl-(inc*1), base+high, tl - (inc * 2), base);
ctx.quadraticCurveTo(tl-(inc*3), base+low, tl - (inc * 4), base);
ctx.quadraticCurveTo(tl-(inc*5), base+high, tl - (inc * 6), base);
ctx.quadraticCurveTo(tl-(inc*7), base+low, tl - (inc * 8), base);
ctx.quadraticCurveTo(tl-(inc*9), base+high, tl - (inc * 10), base);
ctx.closePath();
ctx.fill();
ctx.beginPath();
ctx.fillStyle = "#FFF";
ctx.arc(left + 6,top + 6, s / 6, 0, 300, false);
ctx.arc((left + s) - 6,top + 6, s / 6, 0, 300, false);
ctx.closePath();
ctx.fill();
var f = s / 12;
var off = {};
off[RIGHT] = [f, 0];
off[LEFT] = [-f, 0];
off[UP] = [0, -f];
off[DOWN] = [0, f];
ctx.beginPath();
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#000";
ctx.arc(left+6+off[direction][0], top+6+off[direction][3],
s / 15, 0, 300, false);
ctx.arc((left+s)-6+off[direction][0], top+6+off[direction][4],
s / 15, 0, 300, false);
ctx.closePath();
ctx.fill();
};
function pane(pos) {
if (pos.y === 100 && pos.x >= 190 && direction === RIGHT) {
return {"y": 100, "x": -10};
}
if (pos.y === 100 && pos.x <= -10 && direction === LEFT) {
return position = {"y": 100, "x": 190};
}
return false;
};
function move(ctx) {
var oldPos = position,
onGrid = onGridSquare(position),
npos = null;
if (due !== direction) {
npos = getNewCoord(due, position);
if (onGrid &&
map.isFloorSpace({
"y":pointToCoord(nextSquare(npos.y, due)),
"x":pointToCoord(nextSquare(npos.x, due))})) {
direction = due;
} else {
npos = null;
}
}
if (npos === null) {
npos = getNewCoord(direction, position);
}
if (onGrid &&
map.isWallSpace({
"y" : pointToCoord(nextSquare(npos.y, direction)),
"x" : pointToCoord(nextSquare(npos.x, direction))
})) {
due = getRandomDirection();
return move(ctx);
}
position = npos;
var tmp = pane(position);
if (tmp) {
position = tmp;
}
due = getRandomDirection();
return {
"new" : position,
"old" : oldPos
};
};
return {
"eat" : eat,
"isVunerable" : isVunerable,
"isDangerous" : isDangerous,
"makeEatable" : makeEatable,
"reset" : reset,
"move" : move,
"draw" : draw
};
};
Pacman.User = function (game, map) {
var position = null,
direction = null,
eaten = null,
due = null,
lives = null,
score = 5,
keyMap = {};
keyMap[KEY.ARROW_LEFT] = LEFT;
keyMap[KEY.ARROW_UP] = UP;
keyMap[KEY.ARROW_RIGHT] = RIGHT;
keyMap[KEY.ARROW_DOWN] = DOWN;
function addScore(nScore) {
score += nScore;
if (score >= 10000 && score - nScore < 10000) {
lives += 1;
}
};
function theScore() {
return score;
};
function loseLife() {
lives -= 1;
};
function getLives() {
return lives;
};
function initUser() {
score = 0;
lives = 3;
newLevel();
}
function newLevel() {
resetPosition();
eaten = 0;
};
function resetPosition() {
position = {"x": 90, "y": 120};
direction = LEFT;
due = LEFT;
};
function reset() {
initUser();
resetPosition();
};
function keyDown(e) {
if (typeof keyMap[e.keyCode] !== "undefined") {
due = keyMap[e.keyCode];
e.preventDefault();
e.stopPropagation();
return false;
}
return true;
};
function getNewCoord(dir, current) {
return {
"x": current.x + (dir === LEFT && -2 || dir === RIGHT && 2 || 0),
"y": current.y + (dir === DOWN && 2 || dir === UP && -2 || 0)
};
};
function onWholeSquare(x) {
return x % 10 === 0;
};
function pointToCoord(x) {
return Math.round(x/10);
};
function nextSquare(x, dir) {
var rem = x % 10;
if (rem === 0) {
return x;
} else if (dir === RIGHT || dir === DOWN) {
return x + (10 - rem);
} else {
return x - rem;
}
};
function next(pos, dir) {
return {
"y" : pointToCoord(nextSquare(pos.y, dir)),
"x" : pointToCoord(nextSquare(pos.x, dir)),
};
};
function onGridSquare(pos) {
return onWholeSquare(pos.y) && onWholeSquare(pos.x);
};
function isOnSamePlane(due, dir) {
return ((due === LEFT || due === RIGHT) &&
(dir === LEFT || dir === RIGHT)) ||
((due === UP || due === DOWN) &&
(dir === UP || dir === DOWN));
};
function move(ctx) {
var npos = null,
nextWhole = null,
oldPosition = position,
block = null;
if (due !== direction) {
npos = getNewCoord(due, position);
if (isOnSamePlane(due, direction) ||
(onGridSquare(position) &&
map.isFloorSpace(next(npos, due)))) {
direction = due;
} else {
npos = null;
}
}
if (npos === null) {
npos = getNewCoord(direction, position);
}
if (onGridSquare(position) && map.isWallSpace(next(npos, direction))) {
direction = NONE;
}
if (direction === NONE) {
return {"new" : position, "old" : position};
}
if (npos.y === 100 && npos.x >= 190 && direction === RIGHT) {
npos = {"y": 100, "x": -10};
}
if (npos.y === 100 && npos.x <= -12 && direction === LEFT) {
npos = {"y": 100, "x": 190};
}
position = npos;
nextWhole = next(position, direction);
block = map.block(nextWhole);
if ((isMidSquare(position.y) || isMidSquare(position.x)) &&
block === Pacman.BISCUIT || block === Pacman.PILL) {
map.setBlock(nextWhole, Pacman.EMPTY);
addScore((block === Pacman.BISCUIT) ? 10 : 50);
eaten += 1;
if (eaten === 182) {
game.completedLevel();
}
if (block === Pacman.PILL) {
game.eatenPill();
}
}
return {
"new" : position,
"old" : oldPosition
};
};
function isMidSquare(x) {
var rem = x % 10;
return rem > 3 || rem < 7;
};
function calcAngle(dir, pos) {
if (dir == RIGHT && (pos.x % 10 < 5)) {
return {"start":0.25, "end":1.75, "direction": false};
} else if (dir === DOWN && (pos.y % 10 < 5)) {
return {"start":0.75, "end":2.25, "direction": false};
} else if (dir === UP && (pos.y % 10 < 5)) {
return {"start":1.25, "end":1.75, "direction": true};
} else if (dir === LEFT && (pos.x % 10 < 5)) {
return {"start":0.75, "end":1.25, "direction": true};
}
return {"start":0, "end":2, "direction": false};
};
function drawDead(ctx, amount) {
var size = map.blockSize,
half = size / 2;
if (amount >= 1) {
return;
}
ctx.fillStyle = "#FFFF00";
ctx.beginPath();
ctx.moveTo(((position.x/10) * size) + half,
((position.y/10) * size) + half);
ctx.arc(((position.x/10) * size) + half,
((position.y/10) * size) + half,
half, 0, Math.PI * 2 * amount, true);
ctx.fill();
};
function draw(ctx) {
var s = map.blockSize,
angle = calcAngle(direction, position);
ctx.fillStyle = "#FFFF00";
ctx.beginPath();
ctx.moveTo(((position.x/10) * s) + s / 2,
((position.y/10) * s) + s / 2);
ctx.arc(((position.x/10) * s) + s / 2,
((position.y/10) * s) + s / 2,
s / 2, Math.PI * angle.start,
Math.PI * angle.end, angle.direction);
ctx.fill();
};
initUser();
return {
"draw" : draw,
"drawDead" : drawDead,
"loseLife" : loseLife,
"getLives" : getLives,
"score" : score,
"addScore" : addScore,
"theScore" : theScore,
"keyDown" : keyDown,
"move" : move,
"newLevel" : newLevel,
"reset" : reset,
"resetPosition" : resetPosition
};
};
Pacman.Map = function (size) {
var height = null,
width = null,
blockSize = size,
pillSize = 0,
map = null;
function withinBounds(y, x) {
return y >= 0 && y < height && x >= 0 && x < width;
}
function isWall(pos) {
return withinBounds(pos.y, pos.x) && map[pos.y][pos.x] === Pacman.WALL;
}
function isFloorSpace(pos) {
if (!withinBounds(pos.y, pos.x)) {
return false;
}
var peice = map[pos.y][pos.x];
return peice === Pacman.EMPTY ||
peice === Pacman.BISCUIT ||
peice === Pacman.PILL;
}
function drawWall(ctx) {
var i, j, p, line;
ctx.strokeStyle = "#fFF";
ctx.lineWidth = 5;
ctx.lineCap = "round";
for (i = 0; i < Pacman.WALLS.length; i += 1) {
line = Pacman.WALLS[i];
ctx.beginPath();
for (j = 0; j < line.length; j += 1) {
p = line[j];
if (p.move) {
ctx.moveTo(p.move[0] * blockSize, p.move[1] * blockSize);
} else if (p.line) {
ctx.lineTo(p.line[0] * blockSize, p.line[1] * blockSize);
} else if (p.curve) {
ctx.quadraticCurveTo(p.curve[0] * blockSize,
p.curve[1] * blockSize,
p.curve[2] * blockSize,
p.curve[3] * blockSize);
}
}
ctx.stroke();
}
}
function reset() {
map = Pacman.MAP.clone();
height = map.length;
width = map[0].length;
};
function block(pos) {
return map[pos.y][pos.x];
};
function setBlock(pos, type) {
map[pos.y][pos.x] = type;
};
function drawPills(ctx) {
if (++pillSize > 30) {
pillSize = 0;
}
for (i = 0; i < height; i += 1) {
for (j = 0; j < width; j += 1) {
if (map[i][j] === Pacman.PILL) {
ctx.beginPath();
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#000";
ctx.fillRect((j * blockSize), (i * blockSize),
blockSize, blockSize);
ctx.fillStyle = "#FFF";
ctx.arc((j * blockSize) + blockSize / 2,
(i * blockSize) + blockSize / 2,
Math.abs(5 - (pillSize/3)),
0,
Math.PI * 2, false);
ctx.fill();
ctx.closePath();
}
}
}
};
function draw(ctx) {
var i, j, size = blockSize;
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#000";
ctx.fillRect(0, 0, width * size, height * size);
drawWall(ctx);
for (i = 0; i < height; i += 1) {
for (j = 0; j < width; j += 1) {
drawBlock(i, j, ctx);
}
}
};
function drawBlock(y, x, ctx) {
var layout = map[y][x];
if (layout === Pacman.PILL) {
return;
}
ctx.beginPath();
if (layout === Pacman.EMPTY || layout === Pacman.BLOCK ||
layout === Pacman.BISCUIT) {
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#000";
ctx.fillRect((x * blockSize), (y * blockSize),
blockSize, blockSize);
if (layout === Pacman.BISCUIT) {
ctx.fillStyle = "#FFF";
ctx.fillRect((x * blockSize) + (blockSize / 2.5),
(y * blockSize) + (blockSize / 2.5),
blockSize / 6, blockSize / 6);
}
}
ctx.closePath();
};
reset();
return {
"draw" : draw,
"drawBlock" : drawBlock,
"drawPills" : drawPills,
"block" : block,
"setBlock" : setBlock,
"reset" : reset,
"isWallSpace" : isWall,
"isFloorSpace" : isFloorSpace,
"height" : height,
"width" : width,
"blockSize" : blockSize
};
};
Pacman.Audio = function(game) {
var files = [],
endEvents = [],
progressEvents = [],
playing = [];
function load(name, path, cb) {
var f = files[name] = document.createElement("audio");
progressEvents[name] = function(event) { progress(event, name, cb); };
f.addEventListener("canplaythrough", progressEvents[name], true);
f.setAttribute("preload", "true");
f.setAttribute("autobuffer", "true");
f.setAttribute("src", path);
f.pause();
};
function progress(event, name, callback) {
if (event.loaded === event.total && typeof callback === "function") {
callback();
files[name].removeEventListener("canplaythrough",
progressEvents[name], true);
}
};
function disableSound() {
for (var i = 0; i < playing.length; i++) {
files[playing[i]].pause();
files[playing[i]].currentTime = 0;
}
playing = [];
};
function ended(name) {
var i, tmp = [], found = false;
files[name].removeEventListener("ended", endEvents[name], true);
for (i = 0; i < playing.length; i++) {
if (!found && playing[i]) {
found = true;
} else {
tmp.push(playing[i]);
}
}
playing = tmp;
};
return {
"disableSound" : disableSound,
"load" : load,
"play" : play,
"pause" : pause,
"resume" : resume
};
};
var PACMAN = (function () {
var state = WAITING,
audio = null,
ghosts = [],
ghostSpecs = ["#00FFDE", "#FF0000", "#FFB8DE", "#FFB847"],
eatenCount = 0,
level = 0,
tick = 0,
ghostPos, userPos,
stateChanged = true,
timerStart = null,
lastTime = 0,
ctx = null,
timer = null,
map = null,
user = null,
stored = null;
function getTick() {
return tick;
};
function collided(user, ghost) {
return (Math.sqrt(Math.pow(ghost.x - user.x, 2) +
Math.pow(ghost.y - user.y, 2))) < 10;
};
function drawFooter() {
var topLeft = (map.height * map.blockSize),
textBase = topLeft + 17;
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#000000";
ctx.fillRect(0, topLeft, (map.width * map.blockSize), 30);
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#FFFF00";
for (var i = 0, len = user.getLives(); i < len; i++) {
ctx.fillStyle = "rgba(0, 0, 0, 0)";
//ctx.fillStyle = "#FFFF00";
ctx.beginPath();
ctx.moveTo(150 + (25 * i) + map.blockSize / 2,
(topLeft+1) + map.blockSize / 2);
ctx.arc(150 + (25 * i) + map.blockSize / 2,
(topLeft+1) + map.blockSize / 2,
map.blockSize / 2, Math.PI * 0.25, Math.PI * 1.75, false);
ctx.fill();
}
ctx.fillStyle = !soundDisabled() ? "#00FF00" : "#FF0000";
ctx.font = "bold 16px sans-serif";
//ctx.fillText("♪", 10, textBase);
ctx.fillText("s", 10, textBase);
ctx.fillStyle = "#FFF";
ctx.font = "14px BDCartoonShoutRegular";
ctx.fillText("Score: " + user.theScore(), 30, textBase);
ctx.fillText("Level: " + level, 260, textBase);
}
function redrawBlock(pos) {
map.drawBlock(Math.floor(pos.y/10), Math.floor(pos.x/10), ctx);
map.drawBlock(Math.ceil(pos.y/10), Math.ceil(pos.x/10), ctx);
}
function mainDraw() {
var diff, u, i, len, nScore;
ghostPos = [];
for (i = 0, len = ghosts.length; i < len; i += 1) {
ghostPos.push(ghosts[i].move(ctx));
}
u = user.move(ctx);
for (i = 0, len = ghosts.length; i < len; i += 1) {
redrawBlock(ghostPos[i].old);
}
redrawBlock(u.old);
for (i = 0, len = ghosts.length; i < len; i += 1) {
ghosts[i].draw(ctx);
}
user.draw(ctx);
userPos = u["new"];
for (i = 0, len = ghosts.length; i < len; i += 1) {
ctx.fillStyle = "rgba(0, 0, 0, 0)";
if (collided(userPos, ghostPos[i]["new"])) {
if (ghosts[i].isVunerable()) {
audio.play("eatghost");
ghosts[i].eat();
eatenCount += 1;
nScore = eatenCount * 50;
drawScore(nScore, ghostPos[i]);
user.addScore(nScore);
setState(EATEN_PAUSE);
timerStart = tick;
} else if (ghosts[i].isDangerous()) {
audio.play("die");
setState(DYING);
timerStart = tick;
}
}
}
};
function mainLoop() {
var diff;
if (state !== PAUSE) {
++tick;
}
map.drawPills(ctx);
if (state === PLAYING) {
mainDraw();
} else if (state === WAITING && stateChanged) {
stateChanged = false;
map.draw(ctx);
dialog("Press N to start a New game");
} else if (state === EATEN_PAUSE &&
(tick - timerStart) > (Pacman.FPS / 3)) {
map.draw(ctx);
setState(PLAYING);
} else if (state === DYING) {
if (tick - timerStart > (Pacman.FPS * 2)) {
loseLife();
} else {
redrawBlock(userPos);
for (i = 0, len = ghosts.length; i < len; i += 1) {
redrawBlock(ghostPos[i].old);
//ctx.fillStyle = "rgba(0, 0, 0, 0)";
ghostPos.push(ghosts[i].draw(ctx));
}
user.drawDead(ctx, (tick - timerStart) / (Pacman.FPS * 2));
}
} else if (state === COUNTDOWN) {
diff = 5 + Math.floor((timerStart - tick) / Pacman.FPS);
if (diff === 0) {
map.draw(ctx);
setState(PLAYING);
} else {
if (diff !== lastTime) {
lastTime = diff;
map.draw(ctx);
dialog("Starting in: " + diff);
}
}
}
drawFooter();
}
}());

For every game you want to make, your gameLoop should contain game logic like this (and in advance: GameAlchemist is right, everything should be redrawn every frame):
Clear the whole canvas
Draw background elements (don't use expensive calls, simply draw an image. If you have a lot of drawn elements, such as shapes, lines, etc., make sure to buffer this first on f.e. another, hidden canvas)
Draw more static (background) elements if you want to, that don't change position (f.e. walls)
Draw dynamic elements (your Hero, enemies, bullets, etc.)
Think of all these steps as layers (as in f.e. Photoshop) and make sure to do it in the right order.
This cheat sheet is very helpful.
Also, instead of setInterval, start using requestAnimationFrame. See f.e. this link.
PS Please don't beg for code, in the way you do. Experiment, try, fail, and try again. Then you will learn. Not by asking for gift wrapped pieces of code.