I'm trying to have asteroids moving across the screen for a game. The first few asteroids work and then each asteroid will start blinking and bugging out to the point where they won't move across the screen. The variables acx and acy are the x and y coordinates for the asteroids respectively.
setInterval(throwAsteroid1A, 5000);
function throwAsteroid1A() {
var asteroidCanvas = document.getElementById('asteroidCanvas');
var context = asteroidCanvas.getContext('2d');
var acx = Math.floor(Math.random() * 200);
var acy = Math.floor(Math.random() * 10);
setInterval( () => {
asteroid.onload = function() {
context.drawImage(asteroid, asx, asy, aswidth, asheight, acx, acy, 20, 20);
acx += 1;
acy += 1;
}
asteroid.src = 'https://i.imgur.com/WfQKE6T.png';
}, 10)
setInterval(asteroidPath, 50)
}
function asteroidPath() {
// let computedStyle = getComputedStyle(canvasDisplay)
var asteroidCanvas = document.getElementById('asteroidCanvas');
let ctx = asteroidCanvas.getContext("2d");
ctx.clearRect(acx,acy, canvasDisplay.width, canvasDisplay.height);
}
Well there's obviously something conceptually wrong with your approach. I think the blinking is caused by a timing issue in-between the numerous individual interval timers you set up. The callback function asteroidPath() clears a part of the canvas and this might happen at the same time a new Asteroid has been added to the screen - which will delete it either entirely or partly depending on it's screen position.
To work around it you should:
keep a list of all asteroid objects
clear the screen completely once
update all asteroid's at once - not each one with it's own timer
So an example based on your code might look a little something like this (just click 'Run code snippet'):
Asteroid = function() {
this.acx = Math.floor(Math.random() * 200);
this.acy = Math.floor(Math.random() * 10);
this.image = new Image();
this.image.onload = function(e) {
this.loaded = true;
this.aswidth = e.target.naturalWidth;
this.asheight = e.target.naturalHeight;
}
this.image.src = 'https://i.imgur.com/WfQKE6T.png';
}
var asteroidCanvas = document.getElementById('asteroidCanvas');
var context = asteroidCanvas.getContext('2d');
let asteroids = [];
function spawnAsteroid() {
asteroids.push(new Asteroid());
}
function updateCanvas() {
context.clearRect(0, 0, asteroidCanvas.width, asteroidCanvas.height);
let asteroid;
for (let a = 0; a < asteroids.length; a++) {
asteroid = asteroids[a];
if (asteroid.image.loaded) {
context.drawImage(asteroid.image, 0, 0, asteroid.image.aswidth, asteroid.image.asheight, asteroid.acx, asteroid.acy, 20, 20);
asteroid.acx += 1;
asteroid.acy += 1;
}
}
}
setInterval(spawnAsteroid, 2000);
setInterval(updateCanvas, 50);
spawnAsteroid();
<canvas id="asteroidCanvas"></canvas>
Any ideas how to make switchable characters I have a html game it's finished but I want to implement a way to switch my main character.
Simple coding using Phaser framework
upload function() {
this.game.load.sprite ("bird" assets/bird.png);
this.game.load.sprite ("bird2" assets/bird2.png);
this.game.load.sprite ("bird3" assets/bird3.png);
},
create function() {
this.game.add.sprite (0, 0 "bird" );
},
I want to be able to switch my playable character the "bird" with the "bird2" or "bird3" through a selection button if a player selects a switch character button for the playable character to switch to that. I'm pretty sure this is something simple but I'm still pretty new with coding.
I want a button where I press then I can switch the character
(Button 1) switches to bird2
"if button 1 is selected button two and current bird are disabled"-only bird2 is visible
(Button 2) switches to bird3
"if button 2 is selected button one and current bird are disabled"-only bird3 is visible
Edit This is My current code and states
var MainState = {
//load the game assets before the game starts
preload: function () {
this.load.image('background', 'assets/spring2.png');
this.load.spritesheet('bird', 'assets/bird.png',52 ,28, 7);
this.load.spritesheet('bird2', 'assets/bird2.png',52 ,28, 7);
this.load.spritesheet('bird3', 'assets/bird3.png',52 ,28, 7);
this.load.image('pipe', 'assets/pipe4.png');
},
//executed after everything is loaded
create: function () {
this.background = game.add.tileSprite(0, game.height-736,game.width, 736, 'background');
this.background.autoScroll(-20,0);
/////Bird///////////////////////////////////////////////////
this.bird = this.game.add.sprite(100, 200, 'bird');
this.bird.animations.add('fly');
this.bird.animations.play('fly', 50, true);
game.physics.startSystem(Phaser.Physics.ARCADE);
game.physics.arcade.enable(this.bird);
this.bird.body.gravity.y = 1000;
var spaceKey = game.input.keyboard.addKey(Phaser.Keyboard.SPACEBAR);
this.bird.body.collideWorldBounds=true;
this.bird.body.immovable= true;
game.input.onDown.add(this.jump, this); //////touch screen jump
spaceKey.onDown.add(this.jump, this);
///////////////////////////////////////////////////////Pipes
this.pipes = game.add.group();
//timer
this.timer = game.time.events.loop(1600, this.addRowOfPipes, this); /////////////timer for pipes
///Bird anchor
this.bird.anchor.setTo(-0.2, 0.5)
},
// this is execated multiple times per second
update: function () {
if (this.bird.y < 0 || this.bird.y > 480)
game.state.start("StateOver");
///Collision
game.physics.arcade.overlap(
this.bird, this.pipes, this.restartGame, null, this);
///Bird Angle
if (this.bird.angle < 30)
this.bird.angle += 1;
///////////////music stop w top+bottom collision
if (this.bird.y < 0 || this.bird.y > 479)
music.stop();
},
jump: function () {
//this is for so the bird wount fly once dead
if (this.bird.alive == false)
return;
// Add a vertical velocity to the bird
this.bird.body.velocity.y = -350;
// Jump Animation
var animation = game.add.tween(this.bird);
// Change the angle of the bird to -20° in 100 milliseconds
animation.to({angle: -20}, 100);
// And start the animation
animation.start();
game.add.tween(this.bird).to({angle: -20}, 100).start();
},
restartGame: function () {
// Start the 'main' state, which restarts the game
game.state.start(game.state.StateOver); /////////////////////changed from current #########
///Hit pipe Null
game.physics.arcade.overlap(
this.bird, this.pipes, this.hitPipe, null, this);
},
addRowOfPipes: function() {
var hole = Math.floor(Math.random() * 5) + 1; ///Math.floor(Math.random() * 5) + 1;
for (var i = 0; i < 10 ; i++) ///// (var i = 0; i < 8; i++)
if (i != hole && i != hole + 1) ///// if (i != hole && i != hole + 1)
this.addOnePipe(440, i * 50 ); ///// 640 starting point of pipe 240 point of down ////this.addOnePipe(480, i * 60 + 10);
},
addOnePipe: function(x, y) {
var pipe = game.add.sprite(x, y, 'pipe');
this.pipes.add(pipe);
game.physics.arcade.enable(pipe);
pipe.body.velocity.x = -200;
pipe.checkWorldBounds = true;
pipe.outOfBoundsKill = true;
},
hitPipe: function() {
// If the bird has already hit a pipe, do nothing
// It means the bird is already falling off the screen
if (this.bird.alive == false)
return;
else {
game.state.start("StateOver");
}
// Set the alive property of the bird to false
this.bird.alive = false;
// Prevent new pipes from appearing
game.time.events.remove(this.timer);
// Go through all the pipes, and stop their movement
this.pipes.forEach(function(p){
p.body.velocity.x = 0;
}, this);
},
};
character.js
var characters={
preload:function()
{
game.load.spritesheet('button', 'assets/button.png', 215, 53, 8);
game.load.image("background", "assets/characterbackground.png");
game.load.image("pajaro", "assets/storeicon.png");
game.load.image("logo", "assets/extra/storef.png");
this.load.spritesheet('bird', 'assets/bird.png',52 ,28, 7);
this.load.spritesheet('bird2', 'assets/bird2.png',52 ,28, 7);
this.load.spritesheet('bird3', 'assets/bird3.png',52 ,28, 7);
game.load.spritesheet("button2", 'assets/button2.png', 100, 10, 10);
},
create:function()
{
bird = game.add.image(140, 150, 'pajaro');
logo = game.add.image (20, 350, 'logo');
this.background = game.add.tileSprite(0, game.height-736,game.width, 736, 'background');
this.background.autoScroll(-100,0);
this.btnMainMenu=game.add.button(130,500,'button',this.mainMenu,this,4,5,4);
this.btnbird=game.add.button(180,600,"button2",this.changebird2,this,0,1,0);
},
mainMenu:function()
{
game.state.start("stateTitle");
},
update:function()
{
// bird.x +=1;
},
changebird2: function(){
},
};
Instead of creating three sprites that you either hide or show, I might recommend just changing what texture is loaded when the sprite is created/added.
To do this you'll need to store a reference to the playable character, which you probably already have.
// On the game itself, add a reference.
this.bird = null;
// In your preload, load the different images.
this.load.image('bird', 'assets/bird.png');
this.load.image('bird2', 'assets/bird2.png');
this.load.image('bird3', 'assets/bird3.png');
// When creating, default to one.
this.bird = this.game.add.sprite(0, 0, 'bird');
// In your function where they select a new skin, you can load in a different texture.
this.bird.loadTexture('bird3');
Alternatively, you could store the key that should be used on the game.
// On the game itself, track which key to use.
this.birdSkin = 'bird';
// You'll still have to load your possible textures.
this.load.image('bird', 'assets/bird.png');
this.load.image('bird2', 'assets/bird2.png');
this.load.image('bird3', 'assets/bird3.png');
// Now when creating just use the variable.
this.bird.loadTexture(this.birdSkin);
The Phaser init() will allow 0 or more parameters to be passed in (see the end of Phaser Tutorial: understanding Phaser states), which is where you could populate this.birdSkin.
I would look at what states you're using to determine what's best for you. If you have one state for the game and another for selecting which image/texture is used, than the second option might be better.
Update for Character State
Given your comments and what I saw in your code, I created a short example that you could tweak for your use.
There's a JSFiddle available, but the code is also included below.
var mainState = {
preload: function() {
// Load the three sprites that they can choose between.
this.load.crossOrigin = 'anonymous';
this.load.image('ball', 'https://raw.githubusercontent.com/photonstorm/phaser-examples/master/examples/assets/sprites/orb-blue.png');
this.load.image('ball2', 'https://raw.githubusercontent.com/photonstorm/phaser-examples/master/examples/assets/sprites/orb-green.png');
this.load.image('ball3', 'https://raw.githubusercontent.com/photonstorm/phaser-examples/master/examples/assets/sprites/orb-red.png');
},
create: function() {
this.ball = this.game.add.sprite(this.game.world.centerX, this.game.world.centerY, this.game.global.skin);
this.ball.anchor.setTo(0.5);
// Let the ball be acted upon. This will allow the player to change the sprite used.
this.ball.inputEnabled = true;
this.ball.events.onInputDown.add(this.changeCharacter, this);
},
update: function() {
},
changeCharacter: function() {
game.state.start('character');
}
};
var characterState = {
preload: function() {
},
create: function() {
// For this, add our three possible ball skins.
this.ball1 = this.game.add.sprite(this.game.world.centerX, this.game.world.centerY / 2, 'ball');
this.ball1.anchor.setTo(0.5);
this.ball1.inputEnabled = true;
this.ball2 = this.game.add.sprite(this.game.world.centerX, this.game.world.centerY, 'ball2');
this.ball2.anchor.setTo(0.5);
this.ball2.inputEnabled = true;
this.ball3 = this.game.add.sprite(this.game.world.centerX, this.game.world.centerY * 1.5, 'ball3');
this.ball3.anchor.setTo(0.5);
this.ball3.inputEnabled = true;
// Use the selected ball's sprite in our main game.
this.ball1.events.onInputDown.add(this.selectBall, this);
this.ball2.events.onInputDown.add(this.selectBall, this);
this.ball3.events.onInputDown.add(this.selectBall, this);
},
update: function() {
},
selectBall: function(sprite, pointer) {
// Grab the key of the sprite and save it to our global variable.
this.game.global.skin = sprite.key;
this.game.state.start('main');
}
};
var game = new Phaser.Game(200, 200);
// Create a global object that we can add custom variables to.
game.global = {
skin: 'ball'
};
game.state.add('main', mainState);
game.state.add('character', characterState);
game.state.start('main');
This actually simplifies things a bit, in that it just uses a global variable (I've been using TypeScript the last handful of months, so there's probably a better way to declare this).
I'm trying to create objects on my game update and move them. This is my banana object:
function Banana() {
this.height = 1.96;
this.width = 3.955;
this.pos_x = CENTER - this.width/2;
this.pos_y = -475;
this.banana_image = banana_image;
};
And this is the Move method:
Banana.prototype.move = function(){
if (this.pos_y > 500) {
//this.banana_image.parentElement.removeChild(this.banana_image);
}
this.height += ZOOM_RATE;
this.width += ZOOM_RATE;
this.pos_y += 3;
this.pos_x -= SIDES_RATE;
};
This is the Game Update part:
Game.update = function() {
this.player.move();
//creating bananas
if (objs.lenght <= 0) {
this.banana = new Banana();
} else {
for (i = 0; i < 10; i++) {
objs.push(new Banana());
}
}
//moving bananas
for (i = 0; i < objs.lenght; i++) {
this.objs[0].move();
}
};
Game Draw:
function Game.draw = function() {
this.context.drawImage(road, 0,0, rw, rh);
this.context.drawImage(
this.player.player_image,
this.player.pos_x, this.player.pos_y,
this.player.width, this.player.height);
this.context.drawImage(
this.banana.banana_image,
this.banana.pos_x, this.banana.pos_y,
this.banana.width, this.banana.height);
};
I tried to ask this to multiple people, but I can't find an answer for it.
Let's say you want to move the objects 10 times and then stop.
First you need to add a line to the start of Game.draw, so that it clears the canvas making you always start drawing from scratch:
this.context.clearRect(0,0,500,500); // clear canvas, adjust box size if needed
Then make a function to call both update and draw, and queue that function to be called again:
var count = 10;
function updateAndDraw() {
Game.update();
Game.draw();
count--;
if (count) requestAnimationFrame(updateAndDraw);
}
// start moving:
requestAnimationFrame(updateAndDraw);
The movement may go too fast to your liking, so then adjust the move method to make smaller changes, or use setTimeout instead of requestAnimationFrame (but that will make the animation less fluent).
Note that you have a few errors in your code, which you will need to fix first:
lenght should be length
function Game.draw = function() {: remove function before Game.draw.
... check the error messages you get in console.
i have problem with undo button for my drawing application
<input id="undo" type="image" src="images/undo.ico" onclick="cUndo()" width="25" height="25">
var cPushArray = new Array();
var cStep = -1;
var ctx;
// ctx = document.getElementById('myCanvas').getContext("2d");
function cPush() {
cStep++;
if (cStep < cPushArray.length) { cPushArray.length = cStep; }
cPushArray.push(document.getElementById('myCanvas').toDataURL());
}
function cUndo() {
if (cStep > 0) {
cStep--;
var canvasPic = new Image();
canvasPic.src = cPushArray[cStep];
canvasPic.onload = function () { ctx.drawImage(canvasPic, 0, 0); }
}
}
But this doesn't work.Please help
First remark : As #markE underlines, saving with DataURL has a high memory cost. You might consider saving the draw commands + their arguments within an array instead.
Seek for tuts/Stack Overflow post on the topic, out of a few posts you should get some nice ideas.
Anyway, you can go with the dataURL solution in a first time to get your application working (with a limit of 20 undos or like to avoid memory explosion), then you can later improve the undo to reach a higher limit.
I updated my code to handle such a stack limit.
For your issue : onload should be hooked prior to setting the src, but anyway with a DataURL you are not async : the image is built at once, so no need to hook unload.
var canvas = document.getElementById('myCanvas');
var ctx = canvas.getContext("2d");
var historic = [];
var maxHistoricLength = 20; // might be more or less, depending on canvas size...
function saveForUndo() {
historic.push(canvas.toDataURL());
if (historic.length === maxHistoricLength +1) historic.shift();
}
function canUndo() {
return (historic.length !== 0 );
}
function undo() {
if (!canUndo()) return;
var lastDataURL = historic.pop();
var tmpImage = new Image();
tmpImage.src = lastDataURL;
ctx.drawImage(tmpImage, 0, 0);
}
I'm trying to implement a speedtest by downloading 3 image files from the internet, and averaging the time it took to load them. If there is an error for whatever reason, I want to skip loading that image and proceed with the next one. If the error occurs on the last image, then I want to calculate the average speed at that point and return to the caller.
Right now, once an error occurs (I deliberately changed the url of an image so it doesn't exist), it won't go further. I've tried returning true from the .onerror function, but no luck. Any suggestions?
var images = [{
"url": 'http://<removed>250k.jpg?n=' + Math.random(),
"size": 256000
}, {
"url": 'http://<removed>500k.jpg?n=' + Math.random(),
"size": 512000
}, {
"url": '<removed>1000k.jpg?n=' + Math.random(),
"size": 1024000
}
];
function calculateBandwidth() {
var results = [];
for (var i = 0; i < images.length; i++) {
var startTime, endTime;
var downloadSize = images[i].size;
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
var duration = (endTime - startTime) / 1000;
var bitsLoaded = downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
results.push(speedMbps);
//Calculate the average speed
if (results.length == 3) {
var avg = (parseFloat(results[0]) + parseFloat(results[1]) + parseFloat(results[2])).toFixed(2);
return avg;
}
}
download.onerror = function (e) {
console.log("Failed to load image!");
return true;
};
startTime = (new Date()).getTime();
download.src = images[i].url;
}
}
I think what you're not doing is controlling the process as each event occurs. Each onerror and onload tells you that the process stopped, not that it should quit per se. You initialize one image, it doesn't load, maybe take note, otherwise continue.
The thing is, you do the same thing at the end of onload too. That is, do whatever measurements, then move to the next or, if no more, run the script that cleans up and reports or whatnot.
For instance:
var site = 'http://upload.wikimedia.org/',
imgs = [
'wikipedia/commons/6/6e/Brandenburger_Tor_2004.jpg',
'wikipedia/commons/a/ad/Cegonha_alsaciana.jpg',
'wikipe/Cegonha_alsaciana.jpg',
'wikipedia/commons/d/da/CrayonLogs.jpg',
'wikipedia/commons/1/17/Bobbahn_ep.jpg',
'wikipedia/commons/9/90/DS_Citro%C3%ABn.jpg',
'wikipedia/commons/f/f0/DeutzFahr_Ladewagen_K_7.39.jpg',
'wikipedia/commons/c/c7/DenglerSW-Peach-faced-Lovebird-20051026-1280x960.jpg',
'wikipedia/commons/4/4d/FA-18F_Breaking_SoundBarrier.jpg'
];
My array of images. Hint, wikipe/Cegonha_alsaciana.jpg won't load. Be forewarned, these are large and load slowly and I use a cache buster to keep them firing onloads.
getimg();
In the fiddle, this is all within a window.onload event handler, so when that gets called, this initializes the process. I don't have a setup phase, per se, or otherwise I might have called it init() or setup().
function getimg() {
var img = document.createElement('img'),
path = imgs.shift();
if (path) {
img.onload = loaded;
img.onerror = notloaded;
img.src = site + path + '?cach=bust' + Math.floor(Math.random() * 9999);
console.log('Loading ', img.src);
document.body.appendChild(img);
} else {
console.log('Finished loading images.');
}
function loaded(e) {
console.log('Loaded ', e.target.src);
next();
}
function notloaded(e) {
console.log('Not loaded ', e.target.src);
next();
}
function next() {
console.log(imgs.length, ' imgs left to load.');
getimg();
}
}
http://jsfiddle.net/userdude/vfTfP/
This does what you're trying to do, without the timing mechanism built-in. I can break things off into steps, actions and events, so that I can control the steps as necessary. In a basic way, your script should not run much differently.