Canvas: Movement only allowed on X axis?

Canvas: Movement only allowed on X axis? - javascript

The Problem
I am creating a game where you have to move away from or dodge projectiles coming towards you, I have enabled the user to move the image they are controlling but at the moment the user can place the image anywhere on the canvas.
The Question
How can I only allow the user to move along designated part of the canvas and only along the X axis? for example:
Here is my game, "working progress":
The user is in control of the ship, they should only be able to move left or right like this for example:
The Code
<script>
var game = create_game();
game.init();
//music
var snd = new Audio("menu.mp3");
snd.play();
document.getElementById('mute').addEventListener('click', function (evt) {
if ( snd.muted ) {
snd.muted = false
evt.target.innerHTML = 'mute'
}
else {
snd.muted = true
evt.target.innerHTML = 'unmute'
}
})
function create_game() {
debugger;
var level = 1;
var projectiles_per_level = 1;
var min_speed_per_level = 1;
var max_speed_per_level = 2;
var last_projectile_time = 0;
var next_projectile_time = 0;
var width = 600;
var height = 500;
var delay = 1000;
var item_width = 30;
var item_height = 30;
var total_projectiles = 0;
var projectile_img = new Image();
var projectile_w = 30;
var projectile_h = 30;
var player_img = new Image();
var c, ctx;
var projectiles = [];
var player = {
x: 200,
y: 400,
score: 0
};
function init() {
projectile_img.src = "apple.png";
player_img.src = "basket.png";
level = 1;
total_projectiles = 0;
projectiles = [];
c = document.getElementById("c");
ctx = c.getContext("2d");
ctx.fillStyle = "#ff6600";
ctx.fillRect(0, 0, 500, 600);
c.addEventListener("mousemove", function (e) {
//moving over the canvas.
var bounding_box = c.getBoundingClientRect();
player.x = (e.clientX - bounding_box.left) * (c.width / bounding_box.width) - player_img.width / 2;
player.y = (e.clientY - bounding_box.top) * (c.height / bounding_box.height) - player_img.height / 2;
}, false);
setupProjectiles();
requestAnimationFrame(tick);
}
function setupProjectiles() {
var max_projectiles = level * projectiles_per_level;
while (projectiles.length < max_projectiles) {
initProjectile(projectiles.length);
}
}
function initProjectile(index) {
var max_speed = max_speed_per_level * level;
var min_speed = min_speed_per_level * level;
projectiles[index] = {
x: Math.round(Math.random() * (width - 2 * projectile_w)) + projectile_w,
y: -projectile_h,
v: Math.round(Math.random() * (max_speed - min_speed)) + min_speed,
delay: Date.now() + Math.random() * delay
}
total_projectiles++;
}
function collision(projectile) {
if (projectile.y + projectile_img.height < player.y + 74) {
return false;
}
if (projectile.y > player.y + 74) {
return false;
}
if (projectile.x + projectile_img.width < player.x + 177) {
return false;
}
if (projectile.x > player.x + 177) {
return false;
}
return true;
}
function maybeIncreaseDifficulty() {
level = Math.max(1, Math.ceil(player.score / 10));
setupProjectiles();
}
function tick() {
var i;
var projectile;
var dateNow = Date.now();
c.width = c.width;
for (i = 0; i < projectiles.length; i++) {
projectile = projectiles[i];
if (dateNow > projectile.delay) {
projectile.y += projectile.v;
if (collision(projectile)) {
initProjectile(i);
player.score++;
} else if (projectile.y > height) {
initProjectile(i);
} else {
ctx.drawImage(projectile_img, projectile.x, projectile.y);
}
}
}
ctx.font = "bold 24px sans-serif";
ctx.fillStyle = "#ff6600";
ctx.fillText(player.score, c.width - 50, 50);
ctx.fillText("Level: " + level, 20, 50);
ctx.drawImage(player_img, player.x, player.y);
maybeIncreaseDifficulty();
requestAnimationFrame(tick);
}
return {
init: init
};
}
</script>
JSFiddle (Broken)
https://jsfiddle.net/3oc4jsf6/10/

If your ship is tied to mouse movement, and you want to only allow movement across the X-axis you can simply avoid changing its .y property in your mousemove listener.
Remove this line:
player.y = (e.clientY - bounding_box.top) * (c.height / bounding_box.height) - player_img.height / 2;

Related

Can't read property 'addEventListener' of null

I am working on a college project that requires me to build a 2D game in javascript. A problem that I'm having at the moment is that it cannot read the 'addEventListener'. This error has caused my game to not work completely.
document.getElementById('restart').addEventListener('click', startGame);
Here is the full code that I have used. The error is down the very bottom.
(function()
{
//Define variables
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var player, score, stop, ticker;
var ground = [], water = [], enemies = [], environment = [];
//Platform variables
var platformHeight, platformLength, gapLength;
var platformWidth = 32;
var platformBase = canvas.height - platformWidth;
var platformSpacer = 64;
//Randomly generates a number
function random(low, high)
{
return Math.floor(Math.random() * (high - low + 1) + low);
}
//Bounds a number
function bound(num, low, high)
{
return Math.max(Math.min(num, high), low);
}
//Loads all of the assets
var assetLoader = (function()
{
this.imgs = {
'bg' : 'Images/bg.png',
'sky' : 'Images/sky.png',
'backdrop' : 'Images/backdrop.png',
'backdrop2' : 'Images/backdrop_ground.png',
'grass' : 'Images/grass.png',
'avatar_normal' : 'Images/normal_walk.png',
'water' : 'imgs/water.png',
'grass1' : 'imgs/grassMid1.png',
'grass2' : 'imgs/grassMid2.png',
'bridge' : 'imgs/bridge.png',
'plant' : 'imgs/plant.png',
'bush1' : 'imgs/bush1.png',
'bush2' : 'imgs/bush2.png',
'cliff' : 'imgs/grassCliffRight.png',
'spikes' : 'imgs/spikes.png',
'box' : 'imgs/boxCoin.png',
'slime' : 'imgs/slime.png'
};
var assetsLoaded = 0; //How many assets have been loaded
var numImgs = Object.keys(this.imgs).length; //Total number of image assets
this.totalAssest = numImgs; //Total number of assets
function assetLoaded(dic, name)
{
if(this[dic][name].status !== 'loading')
{
return;
}
this[dic][name].status = 'loaded';
assetsLoaded++;
if(assetsLoaded === this.totalAssest && typeof this.finished === 'function')
{
this.finished();
}
}
this.downloadAll = function()
{
var _this = this;
var src;
for (var img in this.imgs)
{
if (this.imgs.hasOwnProperty(img))
{
src = this.imgs[img];
(function(_this, img)
{
_this.imgs[img] = new Image();
_this.imgs[img].status = 'loading';
_this.imgs[img].name = img;
_this.imgs[img].onload = function() {assetLoaded.call(_this, 'imgs', img)};
_this.imgs[img].src = src;
})(_this, img);
}
}
}
return{
imgs: this.imgs,
totalAssest: this.totalAssest,
downloadAll: this.downloadAll
};
})();
assetLoader.finished = function()
{
startGame();
}
function SpriteSheet(path, frameWidth, frameHeight)
{
this.image = new Image();
this.frameWidth = frameWidth;
this.frameHeight = frameHeight;
var self = this;
this.image.onload = function()
{
self.framesPerRow = Math.floor(self.image.width / self.frameWidth);
};
this.image.src = path;
}
function Animation(spritesheet, frameSpeed, startFrame, endFrame)
{
var animationSequence = [];
var currentFrame = 0;
var counter = 0;
for (var frameNumber = startFrame; frameNumber <= endFrame; frameNumber++)
{
animationSequence.push(frameNumber);
}
this.update = function()
{
if (counter == (frameSpeed - 1))
{
currentFrame = (currentFrame + 1) % animationSequence.length;
}
counter = (counter + 1) % frameSpeed;
};
this.draw = function(x, y)
{
var row = Math.floor(animationSequence[currentFrame] / spritesheet.framesPerRow);
var col = Math.floor(animationSequence[currentFrame] % spritesheet.framesPerRow);
ctx.drawImage
(
spritesheet.image,
col * spritesheet.frameWidth, row * spritesheet.frameHeight,
spritesheet.frameWidth, spritesheet.frameHeight,
x, y,
spritesheet.frameWidth, spritesheet.frameHeight);
};
}
var background = (function()
{
var sky = {};
var backdrop = {};
var backdrop2 = {};
this.draw = function()
{
ctx.drawImage(assetLoader.imgs.bg, 0, 0);
sky.x -= sky.speed;
backdrop.x -= backdrop.speed;
backdrop2.x -= backdrop2.speed;
ctx.drawImage(assetLoader.imgs.sky, sky.x, sky.y);
ctx.drawImage(assetLoader.imgs.sky, sky.x + canvas.width, sky.y);
ctx.drawImage(assetLoader.imgs.backdrop, backdrop.x, backdrop.y);
ctx.drawImage(assetLoader.imgs.backdrop, backdrop.x + canvas.width, backdrop.y);
ctx.drawImage(assetLoader.imgs.backdrop2, backdrop2.x, backdrop2.y);
ctx.drawImage(assetLoader.imgs.backdrop2, backdrop2.x + canvas.width, backdrop2.y);
if (sky.x + assetLoader.imgs.sky.width <= 0)
{
sky.x = 0;
}
if (backdrop.x + assetLoader.imgs.backdrop.width <= 0)
{
backdrop.x = 0;
}
if (backdrop2.x + assetLoader.imgs.backdrop2.width <= 0)
{
backdrop2.x = 0;
}
};
this.reset = function()
{
sky.x = 0;
sky.y = 0;
sky.speed = 0.2;
backdrop.x = 0;
backdrop.y = 0;
backdrop.speed = 0.4;
backdrop2.x = 0;
backdrop2.y = 0;
backdrop2.speed = 0.6;
}
return{
draw: this.draw,
reset: this.reset
};
})();
//A vector for 2D space
function Vector(x, y, dx, dy)
{
// position
this.x = x || 0;
this.y = y || 0;
// direction
this.dx = dx || 0;
this.dy = dy || 0;
}
//Advances the vector's position
Vector.prototype.advance = function()
{
this.x += this.dx;
this.y += this.dy;
};
//Gets the minimum distance between two vectors
Vector.prototype.minDist = function(vec)
{
var minDist = Infinity;
var max = Math.max(Math.abs(this.dx), Math.abs(this.dy),Math.abs(vec.dx), Math.abs(vec.dy));
var slice = 1 / max;
var x, y, distSquared;
// get the middle of each vector
var vec1 = {}, vec2 = {};
vec1.x = this.x + this.width/2;
vec1.y = this.y + this.height/2;
vec2.x = vec.x + vec.width/2;
vec2.y = vec.y + vec.height/2;
for(var percent = 0; percent < 1; percent += slice)
{
x = (vec1.x + this.dx * percent) - (vec2.x + vec.dx * percent);
y = (vec1.y + this.dy * percent) - (vec2.y + vec.dy * percent);
distSquared = x * x + y * y;
minDist = Math.min(minDist, distSquared);
}
return Math.sqrt(minDist);
};
//The player object
var player = (function(player)
{
//Player properties
player.width = 60;
player.height = 96;
player.speed = 6;
//Jumping
player.gravity = 1;
player.dy = 0;
player.jumpDy = -10;
player.isFalling = false;
player.isJumping = false;
//Spritesheets
player.sheet = new SpriteSheet('Images/normal_walk.png', player.width, player.height);
player.walkAnim = new Animation(player.sheet, 4, 0, 15);
player.jumpAnim = new Animation(player.sheet, 4, 15, 15);
player.fallAnim = new Animation(player.sheet, 4, 11, 11);
player.anim = player.walkAnim;
Vector.call(player, 0, 0, 0, player.dy);
var jumpCounter = 0;
player.update = function()
{
//Jump if not currently jumping or falling
if(KEY_STATUS.space && player.dy === 0 && !player.isJumping)
{
player.isJumping = true;
player.dy = player.jumpDy;
jumpCounter = 12;
}
//Jump higher if the spacebar is continually pressed
if(KEY_STATUS.space && jumpCounter)
{
player.dy = player.jumpDy;
}
jumpCounter = Math.max(jumpCounter - 1, 0);
this.advance();
//Gravity
if(player.isFalling || player.isJumping)
{
player.dy += player.gravity;
}
//Falling Animation
if(player.dy > 0)
{
player.anim = player.fallAnim;
}
// change animation is jumping
else if(player.dy < 0)
{
player.anim = player.jumpAnim;
}
else
{
player.anim = player.walkAnim;
}
player.anim.update();
};
//Draw the player's current position
player.draw = function()
{
player.anim.draw(player.x, player.y);
};
//Resets the player's position
player.reset = function()
{
player.x = 64;
player.y = 250;
};
return player;
})(Object.create(Vector.prototype));
//Sprites
function Sprite(x, y, type)
{
this.x = x;
this.y = y;
this.width = platformWidth;
this.height = platformWidth;
this.type = type;
Vector.call(this, x, y, 0, 0);
//Updating the sprites
this.update = function()
{
this.dx = -player.speed;
this.advancer();
}
//Drawing the sprites
this.draw = function()
{
ctx.save();
ctx.translate(0.5, 0.5);
ctx.drawImage(assetLoader.imgs[this.type], this.x, this.y);
ctx.restore();
}
}
Sprite.prototype = Object.create(Vector.prototype);
//Platforms
function getType()
{
var type;
switch(platformHeight)
{
case 0:
case 1:
type = Math.random() > 0.5 ? 'grass1' : 'grass2';
break;
case 2:
type = 'grass';
break;
case 3:
type = 'bridge';
break;
case 4:
type = 'box';
break;
}
if (platformLength === 1 && platformHeight < 3 && rand(0, 3) === 0)
{
type = 'cliff';
}
return type;
}
//Update and draw all ground positions
function updateGround()
{
//Animate ground
player.isFalling = true;
for(var i = 0; i < ground.length; i++)
{
ground[i].update();
ground[i].draw();
//Stop the player going through the platforms when landing
var angle;
if(player.minDist(ground[i]) <= player.height/2 + platformWidth/2 && (angle = Math.atan2(player.y - ground[i].y, player.x - ground[i].x) * 180/Math.PI) > -130 &&angle < -50)
{
player.isJumping = false;
player.isFalling = false;
player.y = ground[i].y - player.height + 5;
player.dy = 0;
}
}
//Remove the ground that has gone off screen
if(ground[0] && ground[0].x < -platformWidth)
{
ground.splice(0, 1);
}
}
//Update and draw all water positions
function updateWater()
{
//Animate water
for(var i = 0; i < water.length; i++)
{
water[i].update();
water[i].draw();
}
//Remove water that has gone off screen
if (water[0] && water[0].x < -platformWidth)
{
var w = water.splice(0, 1)[0];
w.x = water[water.length-1].x + platformWidth;
water.push(w);
}
}
//Update and draw all environment positions
function updateEnvironment()
{
//Animate environment
for(var i = 0; i < environment.length; i++)
{
environment[i].update();
environment[i].draw();
}
//R emove environment that have gone off screen
if(environment[0] && environment[0].x < -platformWidth)
{
environment.splice(0, 1);
}
}
//Update and draw all enemies position. Also check for collision against the player.
function updateEnemies()
{
//Animate enemies
for(var i = 0; i < enemies.length; i++)
{
enemies[i].update();
enemies[i].draw();
//Player ran into enemy
if(player.minDist(enemies[i]) <= player.width - platformWidth/2)
{
gameOver();
}
}
//Remove enemies that have gone off screen
if(enemies[0] && enemies[0].x < -platformWidth)
{
enemies.splice(0, 1);
}
}
//Update and draw the players position
function updatePlayer()
{
player.update();
player.draw();
//Game over
if(player.y + player.height >= canvas.height)
{
gameOver();
}
}
//Spawn new sprites off screen
function spawnSprites()
{
//Increase score
score++;
//First create a gap
if(gapLength > 0)
{
gapLength--;
}
//Then create the ground
else if(platformLength > 0)
{
var type = getType();
ground.push(new Sprite(
canvas.width + platformWidth % player.speed,
platformBase - platformHeight * platformSpacer,
type
));
platformLength--;
//Add random environment sprites
spawnEnvironmentSprites();
//Add random enemies
spawnEnemySprites();
}
//Start over
else
{
//Increase gap length every speed increase of 4
gapLength = rand(player.speed - 2, player.speed);
// only allow a ground to increase by 1
platformHeight = bound(rand(0, platformHeight + rand(0, 2)), 0, 4);
platformLength = rand(Math.floor(player.speed/2), player.speed * 4);
}
}
//Spawn new environment sprites off screen
function spawnEnvironmentSprites()
{
if(score > 40 && rand(0, 20) === 0 && platformHeight < 3)
{
if (Math.random() > 0.5)
{
environment.push(new Sprite(canvas.width + platformWidth % player.speed, platformBase - platformHeight * platformSpacer - platformWidth, 'plant'));
}
else if(platformLength > 2)
{
environment.push(new Sprite(canvas.width + platformWidth % player.speed, platformBase - platformHeight * platformSpacer - platformWidth, 'bush1'));
environment.push(new Sprite(canvas.width + platformWidth % player.speed + platformWidth, platformBase - platformHeight * platformSpacer - platformWidth, 'bush2'));
}
}
}
//Spawn new enemy sprites off screen
function spawnEnemySprites()
{
if(score > 100 && Math.random() > 0.96 && enemies.length < 3 && platformLength > 5 && (enemies.length ? canvas.width - enemies[enemies.length-1].x >= platformWidth * 3 || canvas.width - enemies[enemies.length-1].x < platformWidth : true))
{
enemies.push(new Sprite(canvas.width + platformWidth % player.speed, platformBase - platformHeight * platformSpacer - platformWidth, Math.random() > 0.5 ? 'spikes' : 'slime'));
}
}
//Game Loop
function animate()
{
if(!stop)
{
requestAnimFrame(animate);
ctx.clearRect(0, 0, canvas.width, canvas.height);
background.draw();
//Update entities
updateWater();
updateEnvironment();
updatePlayer();
updateGround();
updateEnemies();
//Draw the score
ctx.fillText('Score: ' + score + 'm', canvas.width - 140, 30);
//Spawn a new Sprite
if(ticker % Math.floor(platformWidth / player.speed) === 0)
{
spawnSprites();
}
//Increase player's speed only when player is jumping
if(ticker > (Math.floor(platformWidth / player.speed) * player.speed * 20) && player.dy !== 0)
{
player.speed = bound(++player.speed, 0, 15);
player.walkAnim.frameSpeed = Math.floor(platformWidth / player.speed) - 1;
//Reset ticker
ticker = 0;
//Spawn a platform to fill in gap created by increasing player speed
if(gapLength === 0)
{
var type = getType();
ground.push(new Sprite(canvas.width + platformWidth % player.speed, platformBase - platformHeight * platformSpacer, type));
platformLength--;
}
}
ticker++;
}
}
//Spacebar events
var KEY_CODES = {
32: 'space'
};
var KEY_STATUS = {};
for(var code in KEY_CODES)
{
if(KEY_CODES.hasOwnProperty(code))
{
KEY_STATUS[KEY_CODES[code]] = false;
}
}
document.onkeydown - function(e)
{
var keyCode = (e.keyCode) ? e.keyCode : e.charCode;
if(KEY_CODES[keyCode])
{
e.preventDefault();
KEY_STATUS[KEY_CODES[keyCode]] = true;
}
};
document.onkeydown - function(e)
{
var keyCode = (e.keyCode) ? e.keyCode : e.charCode;
if(KEY_CODES[keyCode])
{
e.preventDefault();
KEY_STATUS[KEY_CODES[keyCode]] = false;
}
};
//Request Animation Polyfill
var requestAnimFrame = (function()
{
return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(callback, element)
{
window.setTimeout(callback, 1000 / 60);
};
})();
//Start the game and resets all variables and entities, spawn ground and water.
function startGame()
{
document.getElementById('game-over').style.display = 'none';
ground = [];
water = [];
environment = [];
enemies = [];
player.reset();
ticker = 0;
stop = false;
score = 0;
platformHeight = 2;
platformLength = 15;
gapLength = 0;
ctx.font = '16px arial, sans-serif';
for (var i = 0; i < 30; i++)
{
ground.push(new Sprite(i * (platformWidth-3), platformBase - platformHeight * platformSpacer, 'grass'));
}
for (i = 0; i < canvas.width / 32 + 2; i++)
{
water.push(new Sprite(i * platformWidth, platformBase, 'water'));
}
background.reset();
animate();
}
//End the game and restart
function gameOver()
{
stop = true;
document.getElementById('game-over').style.display = 'block';
}
document.getElementById('restart').addEventListener('click', startGame);
assetLoader.downloadAll();
})();

How to store scaled image in HTML5 canvas

I'm creating one drawing app, there I have option to zoom in/out of the canvas image which I have drawn using drawImage() method, after zoom the image I am trying to save the image using toDataUrl() method but its showing blank page after assigning width and height of zoomed image to canvas.
Below code is to save the image after zoomed
destinationCanvas.width = 500; // actual size given with integer values
destinationCanvas.height = 500;
destinationCanvas.style.width = '500px'; // show at 50% on screen
destinationCanvas.style.height = '500px';
var destinationCanvasURL = destinationCanvas.toDataURL();
console.log("markerNormalStyleChange() destinationCanvasURL - "+destinationCanvasURL);
function drawImage(_onScreenMarkingImagePath) {
var canvas = document.getElementById('drawOnScreen');
var ctx = canvas.getContext("2d");
var imageObject = new Image();
var div = $('#drawOnScreenContext'),
w = $(window).width() - 1,
h = $(window).height() - 150;
canvas.width = w;
canvas.height = h ;
$(imageObject).load(function () {
ctx.drawImage(imageObject, 0, 0, w,h);
});
}
Below code is for rawing and zooming the image, here after draw on canvas if I try to zoom then drawn contents will removed because its drawing image only, so for zooming I want to zoom drawn contents also
var requestID;
(function() {
var root = this; //global object
var ImgTouchCanvas = function(options) {
if( !options || !options.canvas || !options.path) {
throw 'ImgZoom constructor: missing arguments canvas or path';
}
this.canvas = options.canvas;
this.canvas.width = this.canvas.clientWidth;
this.canvas.height = this.canvas.clientHeight;
this.context = this.canvas.getContext('2d');
console.log("ImgTouchCanvas() initiated this.canvas.width - "+this.canvas.width);
console.log("ImgTouchCanvas() initiated this.canvas.height - "+this.canvas.height);
this.desktop = options.desktop || false; //non touch events
this.position = {
x: 0,
y: 0
};
this.scale = {
x: 0.5,
y: 0.5
};
this.imgTexture = new Image();
this.imgTexture.src = options.path;
this.lastZoomScale = null;
this.lastX = null;
this.lastY = null;
this.init = false;
this.checkRequestAnimationFrame();
requestID = requestAnimationFrame(this.animate.bind(this));
this.setEventListeners();
};
ImgTouchCanvas.prototype = {
animate: function() {
console.log("ImgTouchCanvas requestAnimationFrame()");
//set scale such as image cover all the canvas
if(!this.init) {
if(this.imgTexture.width) {
var scaleRatio = null;
if(this.canvas.clientWidth > this.canvas.clientHeight) {
scaleRatio = this.canvas.clientWidth / this.imgTexture.width;
}
else {
scaleRatio = this.canvas.clientHeight / this.imgTexture.height;
}
this.scale.x = scaleRatio;
this.scale.y = scaleRatio;
this.init = true;
}
}
//this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
//canvas.width = w;
//canvas.height = h ;
/*this.canvas.width = zoomWidth;
this.canvas.height = zoomHeight;*/
this.context.drawImage(
this.imgTexture,
this.position.x, this.position.y,
this.scale.x * this.imgTexture.width,
this.scale.y * this.imgTexture.height);
console.log("this.scale.x * this.imgTexture.width -- "+this.scale.x * this.imgTexture.width);
console.log("this.scale.y * this.imgTexture.height -- "+this.scale.y * this.imgTexture.height);
mWidth = this.scale.x * this.imgTexture.width;
mHeight = this.scale.y * this.imgTexture.height;
console.log("mWidth -- "+mWidth);
console.log("mHeight -- "+mHeight);
//if($('#pinchZoomInZoomOut').find('#pinchZoomInZoomOutBg').hasClass('btnIconHighLight')) {
//requestAnimationFrame(this.animate.bind(this));
//}else{
//cancelAnimationFrame(this.animate.bind(this));
//}
},
gesturePinchZoom: function(event) {
var zoom = false;
if( event.targetTouches.length >= 2 ) {
var p1 = event.targetTouches[0];
var p2 = event.targetTouches[1];
var zoomScale = Math.sqrt(Math.pow(p2.pageX - p1.pageX, 2) + Math.pow(p2.pageY - p1.pageY, 2)); //euclidian distance
if( this.lastZoomScale ) {
zoom = zoomScale - this.lastZoomScale;
}
this.lastZoomScale = zoomScale;
}
return zoom;
},
doZoom: function(zoom) {
if(!zoom) return;
//new scale
var currentScale = this.scale.x;
var newScale = this.scale.x + zoom/100;
//some helpers
var deltaScale = newScale - currentScale;
var currentWidth = (this.imgTexture.width * this.scale.x);
var currentHeight = (this.imgTexture.height * this.scale.y);
var deltaWidth = this.imgTexture.width*deltaScale;
var deltaHeight = this.imgTexture.height*deltaScale;
//by default scale doesnt change position and only add/remove pixel to right and bottom
//so we must move the image to the left to keep the image centered
//ex: coefX and coefY = 0.5 when image is centered <=> move image to the left 0.5x pixels added to the right
var canvasmiddleX = this.canvas.clientWidth / 2;
var canvasmiddleY = this.canvas.clientHeight / 2;
var xonmap = (-this.position.x) + canvasmiddleX;
var yonmap = (-this.position.y) + canvasmiddleY;
var coefX = -xonmap / (currentWidth);
var coefY = -yonmap / (currentHeight);
var newPosX = this.position.x + deltaWidth*coefX;
var newPosY = this.position.y + deltaHeight*coefY;
//edges cases
var newWidth = currentWidth + deltaWidth;
var newHeight = currentHeight + deltaHeight;
zoomWidth = newWidth;
zoomHeight = newHeight;
//console.log("doZoom() newWidth -- "+newWidth);
//console.log("doZoom() newHeight -- "+newHeight);
if( newWidth < this.canvas.clientWidth ) return;
if( newPosX > 0 ) { newPosX = 0; }
if( newPosX + newWidth < this.canvas.clientWidth ) { newPosX = this.canvas.clientWidth - newWidth;}
if( newHeight < this.canvas.clientHeight ) return;
if( newPosY > 0 ) { newPosY = 0; }
if( newPosY + newHeight < this.canvas.clientHeight ) { newPosY = this.canvas.clientHeight - newHeight; }
//finally affectations
this.scale.x = newScale;
this.scale.y = newScale;
this.position.x = newPosX;
this.position.y = newPosY;
},
doMove: function(relativeX, relativeY) {
if(this.lastX && this.lastY) {
var deltaX = relativeX - this.lastX;
var deltaY = relativeY - this.lastY;
var currentWidth = (this.imgTexture.width * this.scale.x);
var currentHeight = (this.imgTexture.height * this.scale.y);
//console.log("doZoom() currentWidth -- "+currentWidth);
//console.log("doZoom() currentHeight -- "+currentHeight);
this.position.x += deltaX;
this.position.y += deltaY;
//edge cases
if( this.position.x > 0 ) {
this.position.x = 0;
}
else if( this.position.x + currentWidth < this.canvas.clientWidth ) {
this.position.x = this.canvas.clientWidth - currentWidth;
}
if( this.position.y > 0 ) {
this.position.y = 0;
}
else if( this.position.y + currentHeight < this.canvas.clientHeight ) {
this.position.y = this.canvas.clientHeight - currentHeight;
}
}
this.lastX = relativeX;
this.lastY = relativeY;
},
Draw222: function(x, y, isDown) {
//console.log("Draw222() -- "+isDown);
if (isDown) {
this.context.beginPath();
this.context.strokeStyle="#FF0000";
this.context.lineWidth = 5;
this.context.lineJoin = "round";
this.context.moveTo(lx, ly);
this.context.lineTo(x, y);
this.context.closePath();
this.context.stroke();
}
lx = x; ly = y;
},
setEventListeners: function() {
// touch
this.canvas.addEventListener('touchstart', function(e) {
this.lastX = null;
this.lastY = null;
this.lastZoomScale = null;
//newCtx = this.canvas.getContext("2d");
var relativeX = e.targetTouches[0].pageX - this.canvas.getBoundingClientRect().left;
var relativeY = e.targetTouches[0].pageY - this.canvas.getBoundingClientRect().top;
if($('#pinchZoomInZoomOut').find('#pinchZoomInZoomOutBg').hasClass('btnIconHighLight')) {
//requestAnimationFrame(this.animate.bind(this));
}else{
$( '#undoIcon' ).css({
opacity: 1,
pointerEvents: 'auto'
});
cancelAnimationFrame(this.animate.bind(this));
canvasPressed = true;
this.Draw222(parseInt(relativeX), parseInt(relativeY), false);
}
}.bind(this));
this.canvas.addEventListener('touchmove', function(e) {
e.preventDefault();
if(e.targetTouches.length == 2 && $('#pinchZoomInZoomOut').find('#pinchZoomInZoomOutBg').hasClass('btnIconHighLight')) { //pinch
console.log("pinch zoom")
requestID = requestAnimationFrame(this.animate.bind(this));
this.doZoom(this.gesturePinchZoom(e));
}
else {
//console.log("touchmove --- 1")
var relativeX = e.targetTouches[0].pageX - this.canvas.getBoundingClientRect().left;
var relativeY = e.targetTouches[0].pageY - this.canvas.getBoundingClientRect().top;
if($('#pinchZoomInZoomOut').find('#pinchZoomInZoomOutBg').hasClass('btnIconHighLight')) {
//console.log("hasClass btnIconHighLight --- ");
requestID = requestAnimationFrame(this.animate.bind(this));
this.doMove(relativeX, relativeY);
}else{
//console.log("touchmove --- canvasPressed -- "+canvasPressed)
if (canvasPressed) {
cancelAnimationFrame(this.animate.bind(this));
this.Draw222(parseInt(relativeX), parseInt(relativeY), true);
}
}
}
}.bind(this));
this.canvas.addEventListener('touchend', function(e) {
e.preventDefault();
//cPush();
canvasPressed = false;
/*var base64String = null;
var canvas = document.getElementById('drawOnScreen');
var context = canvas.getContext('2d');
// save canvas image as data url (png format by default)
var dataURL = canvas.toDataURL();
console.log("dataURL - "+dataURL);*/
//base64ByteString = dataURL;
//dataURL = dataURL.substr(dataURL.lastIndexOf(',') + 1);
}.bind(this));
},
checkRequestAnimationFrame: function() {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for(var x = 0; x < vendors.length && !window.requestAnimationFrame; ++x) {
window.requestAnimationFrame = window[vendors[x]+'RequestAnimationFrame'];
window.cancelAnimationFrame =
window[vendors[x]+'CancelAnimationFrame'] || window[vendors[x]+'CancelRequestAnimationFrame'];
}
if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function(callback, element) {
var currTime = new Date().getTime();
var timeToCall = Math.max(0, 16 - (currTime - lastTime));
var id = window.setTimeout(function() { callback(currTime + timeToCall); },
timeToCall);
lastTime = currTime + timeToCall;
return id;
};
}
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function(id) {
clearTimeout(id);
};
}
}
};
root.ImgTouchCanvas = ImgTouchCanvas;
}).call(this);
And for pinch zoom in/out the image, I am using this https://github.com/rombdn/img-touch-canvas

how can i make two objects belonging to the same array move independently of each other using javascript and the canvas tag?

I am trying to create a blackhole simulation, where all the balls that are outside of it go away from it at a given speed and those that fall on it are dragged towards the circle until they reach the center of it, where they would stop and disappear, here is my code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<title>blackhole simulation escape velocity</title>
<script>
var canvas, ctx;
var blackhole;
var circle;
var circles = new Array();
var G = 6.67e-11, //gravitational constant
pixel_G = G / 1e-11,
c = 3e8, //speed of light (m/s)
M = 12e31, // masseof the blackhole in kg (60 solar masses)
pixel_M = M / 1e32
Rs = (2 * G * M) / 9e16, //Schwarzchild radius
pixel_Rs = Rs / 1e3, // scaled radius
ccolor = 128;
function update() {
var pos, i, distance, somethingMoved = false;
for (i = 0; i < circles.length; i++) {
pos = circles[i].position;
distance = Math.sqrt(((pos.x - 700) * (pos.x - 700)) + ((pos.y - 400) * (pos.y - 400)));
if (distance > pixel_Rs-5 ) {
var delta = new Vector2D(0, 0);
var forceDirection = Math.atan2(pos.y - 400, pos.x - 700);
var evelocity = Math.sqrt((2 * pixel_G * pixel_M) / (distance * 1e-2));
delta.x += Math.cos(forceDirection) * evelocity;
delta.y += Math.sin(forceDirection) * evelocity;
pos.x += delta.x;
pos.y += delta.y;
somethingMoved = true;
} else {
var delta2 = new Vector2D (0,0);
var forceDirection2 = Math.atan2(pos.y - 400, pos.x - 700);
var g = (pixel_G*pixel_M)/(distance*distance*1e2);
delta2.x += Math.cos(forceDirection2)*g;
delta2.y += Math.sin(forceDirection2)*g;
pos.x -= delta2.x;
pos.y -= delta2.y;
somethingMoved = true;
circles[i].color -= 1;
if (pos.x == 700 && pos.y == 400){
somethingMoved = false;
};
}
}
if (somethingMoved) {
drawEverything();
requestAnimationFrame(update);
};
}
function drawEverything() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
blackhole.draw(ctx);
for (var i = 0; i < circles.length; i++) {
circles[i].draw(ctx);
}
}
function init(event) {
canvas = document.getElementById("space");
ctx = canvas.getContext('2d');
blackhole = new Ball(pixel_Rs, { x: 700,
y: 400 }, 0);
for (var i = 0; i < 200; i++) {
var vec2D = new Vector2D(Math.floor(Math.random() * 1400), Math.floor(Math.random() * 800));
circle = new Ball(5, vec2D, ccolor);
circles.push(circle);
}
drawEverything();
requestAnimationFrame(update);
}
function Ball(radius, position, color) {
this.radius = radius;
this.position = position;
this.color = color;
}
Ball.prototype.draw = function(ctx) {
var c=parseInt(this.color);
ctx.fillStyle = 'rgba(' + c + ',' + c + ',' + c + ',1)';
ctx.beginPath();
ctx.arc(this.position.x, this.position.y, this.radius, 0, 2 * Math.PI);
ctx.closePath();
ctx.fill();
};
function Vector2D(x, y) {
this.x = x;
this.y = y;
}
function onClick (){
canvas = document.getElementById ('space');
ctx = canvas.getContext ('2d')
canvas.addEventListener ("mousedown", init, false)
blackhole = new Ball (5, {x: 700,
y: 400 }, 0);
blackhole.draw (ctx) ;
}
window.onload = onClick;
</script>
<style>
body {
background-color:#021c36 ;
margin: 0px;
}
</style>
</head>
<body>
<canvas id = "space", width = "1400", height = "800">
</canvas>
</body>
</html>
Now as you can see, I created a second variable called delta2, but the problem is that it can't update the position of the circles, which in term makes it impossible to move the circle, can someone tell me what is wrong. Also, how can I make the big black circle after a certain amount of time, i know i probably should create a timer, but i don't know how they work

The gravity is too weak. I put a pseudo gravity to demonstrate.
var canvas, ctx;
var blackhole;
var circle;
var circles = new Array();
var bh = {
w:500,
h:300
};
bh.cx = Math.floor(bh.w/2);
bh.cy = Math.floor(bh.h/2)
var G = 6.67e-11, //gravitational constant
pixel_G = G / 1e-11,
c = 3e8, //speed of light (m/s)
M = 12e31, // masseof the blackhole in kg (60 solar masses)
pixel_M = M / 1e32
Rs = (2 * G * M) / 9e16, //Schwarzchild radius
pixel_Rs = Rs / 1e3, // scaled radius
ccolor = 128;
function update() {
var pos, i, distance, somethingMoved = false;
for (i = 0; i < circles.length; i++) {
pos = circles[i].position;
distance = Math.sqrt(((pos.x - bh.cx) * (pos.x - bh.cx)) + ((pos.y - bh.cy) * (pos.y - bh.cy)));
if (distance > pixel_Rs - 5) {
var delta = new Vector2D(0, 0);
var forceDirection = Math.atan2(pos.y - bh.cy, pos.x - bh.cx);
var evelocity = Math.sqrt((2 * pixel_G * pixel_M) / (distance * 1e-2));
delta.x += Math.cos(forceDirection) * evelocity;
delta.y += Math.sin(forceDirection) * evelocity;
pos.x += delta.x;
pos.y += delta.y;
somethingMoved = true;
} else {
var delta2 = new Vector2D(0, 0);
var forceDirection2 = Math.atan2(pos.y - bh.cy, pos.x - bh.cx);
// FIX THIS!!!
var g = 1;//(pixel_G * pixel_M) / (distance * distance * 1e2);
delta2.x += Math.cos(forceDirection2) * g;
delta2.y += Math.sin(forceDirection2) * g;
pos.x -= delta2.x;
pos.y -= delta2.y;
somethingMoved = true;
circles[i].color -= 1;
if (pos.x == bh.cx && pos.y == bh.cy) {
somethingMoved = false;
};
}
}
if (somethingMoved) {
drawEverything();
requestAnimationFrame(update);
};
}
function drawEverything() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
blackhole.draw(ctx);
for (var i = 0; i < circles.length; i++) {
circles[i].draw(ctx);
}
}
function init(event) {
canvas = document.getElementById("space");
canvas.width = bh.w;
canvas.height = bh.h;
ctx = canvas.getContext('2d');
blackhole = new Ball(5, { //pixel_Rs, {
x: bh.cx,
y: bh.cy
}, 0);
for (var i = 0; i < 200; i++) {
var vec2D = new Vector2D(Math.floor(Math.random() * bh.w), Math.floor(Math.random() * bh.h));
circle = new Ball(5, vec2D, ccolor);
circles.push(circle);
}
drawEverything();
requestAnimationFrame(update);
}
function Ball(radius, position, color) {
this.radius = radius;
this.position = position;
this.color = color;
}
Ball.prototype.draw = function(ctx) {
var c = parseInt(this.color);
ctx.fillStyle = 'rgba(' + c + ',' + c + ',' + c + ',1)';
ctx.beginPath();
ctx.arc(this.position.x, this.position.y, this.radius, 0, 2 * Math.PI);
ctx.closePath();
ctx.fill();
};
function Vector2D(x, y) {
this.x = x;
this.y = y;
}
function onClick() {
canvas = document.getElementById('space');
ctx = canvas.getContext('2d')
canvas.addEventListener("mousedown", init, false)
blackhole = new Ball(5, {
x: bh.cx,
y: bh.cy
}, 0);
blackhole.draw(ctx);
}
window.onload = onClick;
body {
background-color: #021c36;
margin: 0px;
}
<canvas id="space" , width="700" , height="400"></canvas>

Why does my Javascript animation slowdown after a while

So I am in the process of making this rhythm game with canvas, all that it does up to this point is render the receivers (the point the blocks are going to collide with so the user can press the corresponding buttons and get points) and it renders the dancer animation. For some reason though after the page is open for a while the dancer slows down significantly and continues to gradually slow.
I can't figure out why or how to fix it. Anyone have any ideas?
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
canvas.width = 500;
canvas.height = 600;
document.body.appendChild(canvas);
var spritesheet = null;
var dancer = {
time:0,
speed:0,
image:null,
x:0,
y:0,
currentFrame:0,
width:50,
height:100,
ready:false
}
function onload() {
spritesheet = new Image();
spritesheet.src = "danceSheet.png";
spritesheet.onload = initiate;
}
function initiate() {
game.startTime = new Date().getTime() / 1000;
dancer.x = (canvas.width / 2) - dancer.width;
dancer.y = 120;
game.initiateReceivers();
main();
}
var game = {
startTime:0,
currentTime:0,
receivers:[],
senders:[],
lanes:[],
drawDancer: function() {
ctx.drawImage(spritesheet, dancer.width * dancer.currentFrame, 0, dancer.width, dancer.height, dancer.x, dancer.y, dancer.width, dancer.height );
},
clearWindow: function() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
},
initiateReceivers: function() {
var distanceRate = canvas.width / 4;
var position = 30;
for(initiates = 0; initiates < 4; initiates++) {
this.receivers[initiates] = new receivers;
this.receivers[initiates].x = position;
this.receivers[initiates].y = 300;
position += distanceRate;
}
}
}
var gameUpdates = {
updateMovement: function() {
game.currentTime = new Date().getTime() / 1000;
dancer.time = game.currentTime - game.startTime;
if(dancer.time >= 0.1) {
game.startTime = new Date().getTime() / 1000;
dancer.currentFrame += 1;
if(dancer.currentFrame == 12) dancer.currentFrame = 0;
}
},
collision: function(shapeA, shapeB) {
// get the vectors to check against
var vX = (shapeA.x + (shapeA.width / 2)) - (shapeB.x + (shapeB.width / 2)),
vY = (shapeA.y + (shapeA.height / 2)) - (shapeB.y + (shapeB.height / 2)),
// add the half widths and half heights of the objects
hWidths = (shapeA.width / 2) + (shapeB.width / 2),
hHeights = (shapeA.height / 2) + (shapeB.height / 2);
// if the x and y vector are less than the half width or half height, they we must be inside the object, causing a collision
if (Math.abs(vX) < hWidths && Math.abs(vY) < hHeights) {
return true;
}
return false;
}
}
function receivers() {
this.x = 0;
this.y = 0;
this.width = 60;
this.height = 10;
}
function senders() {
this.x = 0;
this.y = 0;
this.width = 60;
this.height = 10;
this.lane = 0;
this.status = true;
}
function update() {
gameUpdates.updateMovement();
}
function render() {
game.clearWindow();
game.drawDancer();
game.receivers.forEach( function(receiver) {
ctx.rect(receiver.x,receiver.y,receiver.width,receiver.height);
ctx.fillStyle = "red";
ctx.fill();
}
)
}
function main() {
update();
render();
requestAnimationFrame(main);
}

I'm trying to get an idea of the slowness you're seeing so I adjusted your code to get a frames-per-second. Haven't found the cause yet for the drop.
Update
I found that the frames were dropping from drawing the rectangles. I've altered the code to use fillRect put the fill style outside of the loop. This seems to have fixed the frame drop.
var canvas = document.createElement("canvas");
var ctx = canvas.getContext("2d");
canvas.width = 500;
canvas.height = 600;
document.body.appendChild(canvas);
var spritesheet = null;
var dancer = {
time: 0,
speed: 0,
image: null,
x: 0,
y: 0,
currentFrame: 0,
width: 50,
height: 100,
ready: false
}
function onload() {
spritesheet = document.createElement('canvas');
spritesheet.width = (dancer.width * 12);
spritesheet.height = dancer.height;
var ctx = spritesheet.getContext('2d');
ctx.font = "30px Arial";
ctx.fillStyle = "black";
ctx.strokeStyle = "red";
for (var i = 0; i < 12; i++) {
var x = (i * dancer.width) + 10;
ctx.fillText(i,x,60);
ctx.beginPath();
ctx.rect(i*dancer.width,0,dancer.width,dancer.height);
ctx.stroke();
}
initiate();
}
function initiate() {
game.startTime = new Date().getTime() / 1000;
dancer.x = (canvas.width / 2) - dancer.width;
dancer.y = 120;
game.initiateReceivers();
main();
}
var game = {
startTime: 0,
currentTime: 0,
receivers: [],
senders: [],
lanes: [],
drawDancer: function() {
ctx.drawImage(spritesheet, dancer.width * dancer.currentFrame, 0, dancer.width, dancer.height, dancer.x, dancer.y, dancer.width, dancer.height);
//ctx.strokeStyle="red";
//ctx.beginPath();
//ctx.lineWidth = 3;
//ctx.rect(dancer.x,dancer.y,dancer.width,dancer.height);
//ctx.stroke();
},
clearWindow: function() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
},
initiateReceivers: function() {
var distanceRate = canvas.width / 4;
var position = 30;
for (initiates = 0; initiates < 4; initiates++) {
this.receivers[initiates] = new receivers;
this.receivers[initiates].x = position;
this.receivers[initiates].y = 300;
position += distanceRate;
}
}
};
var gameUpdates = {
updateMovement: function() {
game.currentTime = new Date().getTime() / 1000;
dancer.time = game.currentTime - game.startTime;
if (dancer.time >= 0.1) {
game.startTime = new Date().getTime() / 1000;
dancer.currentFrame += 1;
if (dancer.currentFrame == 12) dancer.currentFrame = 0;
}
},
collision: function(shapeA, shapeB) {
// get the vectors to check against
var vX = (shapeA.x + (shapeA.width / 2)) - (shapeB.x + (shapeB.width / 2)),
vY = (shapeA.y + (shapeA.height / 2)) - (shapeB.y + (shapeB.height / 2)),
// add the half widths and half heights of the objects
hWidths = (shapeA.width / 2) + (shapeB.width / 2),
hHeights = (shapeA.height / 2) + (shapeB.height / 2);
// if the x and y vector are less than the half width or half height, they we must be inside the object, causing a collision
if (Math.abs(vX) < hWidths && Math.abs(vY) < hHeights) {
return true;
}
return false;
}
}
function receivers() {
this.x = 0;
this.y = 0;
this.width = 60;
this.height = 10;
}
function senders() {
this.x = 0;
this.y = 0;
this.width = 60;
this.height = 10;
this.lane = 0;
this.status = true;
}
function update() {
gameUpdates.updateMovement();
}
function render() {
game.clearWindow();
game.drawDancer();
ctx.fillStyle = "red";
game.receivers.forEach(function(receiver) {
ctx.fillRect(receiver.x, receiver.y, receiver.width, receiver.height);
});
ctx.fillText(fps,10,10);
}
var fps = 0;
var frames = 0;
function getFps() {
fps = frames;
frames = 0;
setTimeout(getFps,1000);
}
getFps();
function main() {
update();
render();
frames++;
requestAnimationFrame(main);
}
onload();
canvas {
border:1px solid blue;
}

How can i get the multiple apple/s to fall? [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 7 years ago.
Improve this question
I am creating a game (using HTML5 canvas) that involves catching falling apples, i know, how original! I am having trouble finding a way to make it so multiple apples fall?
Here is the code in JSFiddle: https://jsfiddle.net/pgkL09j7/12/
var apple_x = 100;
var apple_y = 0;
var basket_x = 100;
var basket_y = 100;
var points = 0;
var basket_img = new Image();
basket_img.src = "http://s18.postimg.org/h0oe1vj91/basket.png";
var Countable = function () {}
//Background colour of canvas
var c = document.getElementById("c");
var ctx = c.getContext("2d");
ctx.fillStyle = "#000";
ctx.fillRect(0, 0, 500, 500);
//Here is the event listener
c.addEventListener("mousemove", seenmotion, false);
//////////////////////
function seenmotion(e) {
//This is the code for the mouse
//moving over the canvas.
var bounding_box = c.getBoundingClientRect();
basket_x = (e.clientX - bounding_box.left) * (c.width / bounding_box.width) - basket_img.width / 2;
basket_y = (e.clientY - bounding_box.top) * (c.height / bounding_box.height) - basket_img.height / 2;
}
function start_game() {
setInterval(game_loop, 50);
}
function game_loop() {
// The code above is called every 50ms and is a
// frame-redraw-game-animation loop.
c.width = c.width;
// Below is the code that draws the objects
draw_apple(apple_x, apple_y);
draw_basket(basket_x, basket_y);
// Below is the code that updates the balloons location
apple_x++;
if (apple_y > c.height) {
apple_y = 0;
}
//Here is the collision detection code
if (collision(apple_x, apple_y, basket_x, basket_y)) {
points -= 0.5;
}
//Here is the code for the point system
points += 1;
// and let's stick it in the top right.
var integerpoints = Math.floor(points); // make it into an integer
ctx.font = "bold 24px sans-serif";
ctx.fillText(integerpoints, c.width - 50, 50);
}
context.clearRect(0, 0, 500, 500);
function collision(basket_x, basket_y, apple_x, apple_y) {
if (apple_y + 85 < basket_y) {
return false;
}
if (apple_y > basket_y + 91) {
return false;
}
if (apple_x + 80 < basket_x) {
return false;
}
if (apple_x > basket_x + 80) {
return false;
}
return true;
}
// Code to stop the game when we're finished playing
function stop_game() {
}
//Code for the ball
function draw_app
le(x, y) {
var apple_img = new Image();
apple_img.src = "http://s15.postimg.org/3nwjmzsiv/apple.png";
ctx.drawImage(apple_img, x, y);
}
//Code for the basket
function draw_basket(x, y) {
ctx.drawImage(basket_img, x, y);
}

Change the section
apple_x++;
if (apple_x > c.width) {
apple_x = 0;
}
to use vertical instead of horizontal...
apple_y++;
if (apple_y > c.height) {
apple_y = 0;
}

You've already accepted the answer, but this looked like fun. Check out this fiddle.
https://jsfiddle.net/h82gv4xn/
Improvements include:
Fixed scoreboard
Added level progression (Level increases every 10 apples)
Allowance for many many more apples on screen (play to level 9).
Apples will fall at different speeds and speed up as the levels increase.
Uses the animation frame system for much smoother animations.
Relaxed collision handling (The center of the bucket must touch the apple)
It all gets really silly as the levels wind upwards, but it should be a nice example to improve upon. The relevant javascript follows (this would go into your onLoad function):
var game = create_game();
game.init();
function create_game() {
debugger;
var level = 1;
var apples_per_level = 1;
var min_speed_per_level = 1;
var max_speed_per_level = 2;
var last_apple_time = 0;
var next_apple_time = 0;
var width = 500;
var height = 500;
var delay = 1000;
var item_width = 50;
var item_height = 50;
var total_apples = 0;
var apple_img = new Image();
var apple_w = 50;
var apple_h = 50;
var basket_img = new Image();
var c, ctx;
var apples = [];
var basket = {
x: 100,
y: 100,
score: 0
};
function init() {
apple_img.src = "http://s15.postimg.org/3nwjmzsiv/apple.png";
basket_img.src = "http://s18.postimg.org/h0oe1vj91/basket.png";
level = 1;
total_apples = 0;
apples = [];
c = document.getElementById("c");
ctx = c.getContext("2d");
ctx.fillStyle = "#000";
ctx.fillRect(0, 0, 500, 500);
c.addEventListener("mousemove", function (e) {
//moving over the canvas.
var bounding_box = c.getBoundingClientRect();
basket.x = (e.clientX - bounding_box.left) * (c.width / bounding_box.width) - basket_img.width / 2;
basket.y = (e.clientY - bounding_box.top) * (c.height / bounding_box.height) - basket_img.height / 2;
}, false);
setupApples();
requestAnimationFrame(tick);
}
function setupApples() {
var max_apples = level * apples_per_level;
while (apples.length < max_apples) {
initApple(apples.length);
}
}
function initApple(index) {
var max_speed = max_speed_per_level * level;
var min_speed = min_speed_per_level * level;
apples[index] = {
x: Math.round(Math.random() * (width - 2 * apple_w)) + apple_w,
y: -apple_h,
v: Math.round(Math.random() * (max_speed - min_speed)) + min_speed,
delay: Date.now() + Math.random() * delay
}
total_apples++;
}
function collision(apple) {
if (apple.y + apple_img.height < basket.y + 50) {
return false;
}
if (apple.y > basket.y + 50) {
return false;
}
if (apple.x + apple_img.width < basket.x + 50) {
return false;
}
if (apple.x > basket.x + 50) {
return false;
}
return true;
}
function maybeIncreaseDifficulty() {
level = Math.max(1, Math.ceil(basket.score / 10));
setupApples();
}
function tick() {
var i;
var apple;
var dateNow = Date.now();
c.width = c.width;
for (i = 0; i < apples.length; i++) {
apple = apples[i];
if (dateNow > apple.delay) {
apple.y += apple.v;
if (collision(apple)) {
initApple(i);
basket.score++;
} else if (apple.y > height) {
initApple(i);
} else {
ctx.drawImage(apple_img, apple.x, apple.y);
}
}
}
ctx.font = "bold 24px sans-serif";
ctx.fillStyle = "#2FFF2F";
ctx.fillText(basket.score, c.width - 50, 50);
ctx.fillText("Level: " + level, 20, 50);
ctx.drawImage(basket_img, basket.x, basket.y);
maybeIncreaseDifficulty();
requestAnimationFrame(tick);
}
return {
init: init
};
}

We Keep Coding

JavaScript is the programming language of the Web.

Canvas: Movement only allowed on X axis? - javascript

If your ship is tied to mouse movement, and you want to only allow movement across the X-axis you can simply avoid changing its .y property in your mousemove listener. Remove this line: player.y = (e.clientY - bounding_box.top) * (c.height / bounding_box.height) - player_img.height / 2;

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