I am using KineticJS to perform HTML Canvas animations. Animations work perfectly on all desktop browsers, and non retina iDevices (including iPad mini). However, from a retina device (browser or in-app webview using appcelerator) these animations are very sluggish. I have seen similar issues with canvas animations on retina display, but have not found any true solution.
My Stage constructor is 1024w x 768h.
All images are preloaded. And animations are constructed using the preloader's callback function.
If I reduce my stage size by half (and scale inner contents accordingly), the animation will play almost normally (still a little choppier than other ipads). My only justification for trying this was my very poor understanding that a retina display is two 'points'/pixel.
Any insight or ideas are welcome. My next attempt is to start changing image resolutions, rather than scaling dynamically.
This is due to a feature added four months ago. KineticJS will recognize if the pixelratio of the device is over 1 and try to make it as sharp as with pixelratio 1. The problem is, like you have found out, that it kills the performance to the point that it's useless. We have found this to be the case for our use cases.
Our solution: We commented out the pixel ratio part in KineticJS and hard coded it to always be one.
Pros:
The performance goes back up to normal
Cons:
Image is not as sharp
This is the part where we have made the change:
Kinetic.Canvas = function(width, height, pixelRatio) {
// eduplus change to fix pixel ratio performance problems
this.pixelRatio = 1; //pixelRatio || _pixelRatio;
When discussing this with Eric, he made comments to investigate pixel ratio performance, but I don't think he has had the time to do that yet. Hope this helps!
Using KineticJS 5 or above (I am not sure when exactly this global setting was introduced), the simplest and least intrusive way to do this is to set Kinetic.pixelRatio to your desired value before instantiating your stage:
Kinetic.pixelRatio = 1;
var stage = new Kinetic.Stage({
...
});
I use this before instantiating my Stage to overload pixelRatio without modifying KineticJS's source file. (Saves you from having to update the source file after any updates.)
https://gist.github.com/echong/6107722
CoffeeScript:
# Adjust device pixel ratio
for className in ["HitCanvas", "SceneCanvas", "Canvas"]
Kinetic[className].prototype.init = ((p_method) -> (p_config={}) ->
p_config.pixelRatio = 1
p_method.call #, p_config
) Kinetic[className].prototype.init
JavaScript:
_ref = ["HitCanvas", "SceneCanvas", "Canvas"];
for (_i = 0, _len = _ref.length; _i < _len; _i++) {
className = _ref[_i];
Kinetic[className].prototype.init = (function(p_method) {
return function(p_config) {
if (p_config == null) {
p_config = {};
}
p_config.pixelRatio = 1;
return p_method.call(this, p_config);
};
})(Kinetic[className].prototype.init);
}
Related
I've got an issue with an experiment I'm working on.
My plan is to have a beautiful and shining stars Background on a whole page.
Using that wondeful tutorial (http://timothypoon.com/blog/2011/01/19/html5-canvas-particle-animation/) I managed to get the perfect background.
I use a static canvas to display static stars and an animated canvas for the shining ones.
The fact is it's very memory hungry! On chrome and opera it runs quite smoothly, but on firefox IE or tablet, it was a total mess 1s to render each frame etc... It is worse on pages where HEIGHT is huge.
So i went into some optimisations:
-Using a buffer canvas, the problem was createRadialGradient which was called 1500 times each frame
-Using a big buffer canvas, and 1 canvas for each stars with an only call to createRadialGradient at init.
-Remove that buffer canvas and drawing every stars canvas to the main one
That last optimisation was the best i could achieve so i wrote a fiddle displaying how is the code right now.
//Buffering the star image
this.scanvas = document.createElement('canvas');
this.scanvas.width=2*this.r;
this.scanvas.height=2*this.r;
this.scon=this.scanvas.getContext('2d');
g = this.scon.createRadialGradient(this.r,this.r,0,this.r,this.r,this.r);
g.addColorStop(0.0, 'rgba(255,255,255,0.9)');
g.addColorStop(this.stop, 'rgba('+this.color.r+','+this.color.g+','+this.color.b+','+this.stop+')');
g.addColorStop(1.0, 'rgba('+this.color.r+','+this.color.g+','+this.color.b+',0)');
this.scon.fillStyle = g;
this.scon.fillRect(0,0,2*this.r,2*this.r);
That's the point where I need you:
-A way to adjust the number of shining stars according to the user perfomance
-Optimisation tips
Thanks in advance to everyone minding to help me and I apologize if I made grammar mistakes, my english isn't perfect.
EDIT
Thanks for your feedbacks,
Let me explains the whole process,
Every stars has it's own different gradient and size, that's why I stored it into a personal canvas, the shining effect is only done by scaling that canvas on the main one with drawImage.
I think the best would be to prerender 50 or 100 different stars in a buffer canvas then picking and drawing a random one, don't you think?
EDIT2
Updated fiddle according to Warlock great advises, one prerendered star, scaled to match the current size. The stars are less pretty, but the whole thing runs a lot smoother.
EDIT3
Updated fiddle to use a sprite sheet. Gorgeous!!!!
//generate the star strip
var len=(ttlm/rint)|0;
scanvas = document.createElement('canvas');
scanvas.width=len*2*r;
scanvas.height=2*r;
scon=scanvas.getContext('2d');
for(var i=0;i<len;i++){
var newo = (i/len);
var cr = r*newo;
g = scon.createRadialGradient(2*r*i+r,r,0,2*r*i+r,r,(cr <= 2 ? 2 : cr));
g.addColorStop(0.0, 'rgba(200,220,255,'+newo+')');
g.addColorStop(0.2, 'rgba(200,220,255,'+(newo*.7)+')');
g.addColorStop(0.4, 'rgba(150,170,205,'+(newo*.2)+')');
g.addColorStop(0.7, 'rgba(150,170,205,0)');
scon.fillStyle = g;
scon.fillRect(2*r*i,0,2*r,2*r);
}
EDIT 4(Final)
Dynamic stars creations
function draw() {
frameTime.push(Date.now());
con.clearRect(0,0,WIDTH,HEIGHT);
for(var i = 0, len = pxs.length; i < len; i++) {
pxs[i].fade();
pxs[i].draw();
}
requestAnimationFrame(draw);
if(allowMore === true && frameTime.length == monitoredFrame)
{
if(getAvgTime()<threshold && pxs.length<totalStars )
{
addStars();
}
else
{
allowMore=false;
static=true;
fillpxs(totalStars-pxs.length,pxss);
drawstatic();
static=false;
}
}
}
Here is the updated and final fiddle, with spritesheet, dynamic stars creation and several optimisations. If you see anything else i should update don't hesitate.
POST EDIT Reenabled shooting stars/Prototyped object/got rid of Jquery
http://jsfiddle.net/macintox/K8YTu/32/
Thanks everyone who helped me, that was really kind and instructive, and I hope it will help somebody sometimes.
Aesdotjs.
PS: I'm so happy. After testing, that script run smoothly on every browser even IE9. Yatta!!
Adopting to browser performance
To measure capability of the user's setup you can implement a dynamic star creator which stops at a certain threshold.
For example, in your code you define a minimum number of stars to draw. Then in your main loop you measure the time and if the time spent drawing the stars are less than your max threshold you add 10 more stars (I'm just throwing out a number here).
Not many are aware of that requestAnimationFrame gives an argument (DOMHighResTimeStamp) to the function it calls with time in milliseconds spent since last request. This will help you keep track of load and as we know that 60 fps is about 16.7 ms per frame we can set a threshold a little under this to be optimal and still allow some overhead for other browser stuff.
A code could look like this:
var minCount = 100, /// minimum number of stars
batchCount = 10, /// stars to add each frame
threshold= 14, /// milliseconds for each frame used
allowMore = true; /// keep adding
/// generate initial stars
generateStarts(minCount);
/// timeUsed contains the time in ms since last requestAnimationFrame was called
function loop(timeUsed) {
if (allowMore === true && timeUsed < threshold) {
addMoreStars(batchNumber);
} else {
allowMore = false;
}
/// render stars
requestAnimationFrame(loop);
}
Just note that this is a bit simplified. You will need to run a few rounds first and measure the average to have this work better as you can and will get peak when you add stars (and due to other browser operations).
So add stars, measure a few rounds, if average is below threshold add stars and repeat.
Optimizations
Sprite-sheets
As to optimizations sprite-sheets are the way to go. And they don't have to just be the stars (I'll try to explain below).
The gradient and arc is the costly part of this applications. Even when pre-rendering a single star there is cost in resizing so many stars due to interpolation etc.
When there becomes a lot of costly operations it is better to do a compromise with memory usage and pre-render everything you can.
For example: render the various sizes by first rendering a big star using gradient and arc.
Use that star to draw the other sizes as a strip of stars with the same cell size.
Now, draw only half of the number of stars using the sprite-sheet and draw clipped parts of the sprite-sheet (and not re-sized). Then rotate the canvas 90 degrees and draw the canvas itself on top of itself in a different position (the canvas becoming a big "sprite-sheet" in itself).
Rotating 90 degrees is not so performance hungry as other degrees (0, 90, 180, 270 are optimized). This will give you the illusion of having the actual amount of stars and since it's rotated we are not able to detect a repetitive pattern that easy.
A single drawImage operation of canvas is faster than many small draw operations of all the stars.
(and of course, you can do this many times instead of just once up to a point right before where you start see patterns - there is no key answer to how many, what size etc. so to find the right balance is always an experiment).
Integer numbers
Other optimizations can be using only integer positions and sizes. When you use float numbers sub-pixeling is activated which is costly as the browser need to calculate anti-alias for the offset pixels.
Using integer values can help as sub-pixeling isn't needed (but this doesn't mean the image won't be interpolated if not 1:1 dimension).
Memory bounds
You can also help the underlying low-lowel bitmap handling a tiny bit by using sizes and positions dividable on 4. This has to do with memory copy and low-level clipping. You can always make several sprite-sheet to variate positions within a cell that is dividable on 4.
This trick is more valuable on slower computers (ie. typical consumer spec'ed computers).
Turn off anti-aliasing
Turn off anti-aliasing for images. This will help performance but will give a little more rough result of the stars. To turn off image anti-aliasing do this:
ctx.webkitEnableImageSmoothing = false;
ctx.mozEnableImageSmoothing = false;
ctx.enableImageSmoothing = false;
You will by doing this see a noticeable improvement in performance as long as you use drawImage to render the stars.
Cache everything
Cache everything you can cache, being the star image as well as variables.
When you do this stars.length the browser's parser need to first find stars and then traverse that tree to find length - for each round (this may be optimized in some browsers).
If you first cache this to a variable var len = stars.length the browser only need to traverse the tree and branch once and in the loop it will only need to look up the local scope to find variable len which is faster.
Resolution reduction
You can also reduce resolution in half, ie. do everything at half the target size. In the final step draw your render enlarged to full size. This will save you initially 75% render area but give you a bit low-res look as a result.
From the professional video world we often use low-resolution when things are animated (primarily moving) as the eye/brain patch up (or can't detect) so much details when objects are moving and therefor isn't so noticeable. If this can help here must be tested - perhaps not since the stars aren't actually moving, but worth a try for the second benefit: increased performance.
How about just creating a spritesheet of a star in its various stages of radial glow.
You could even use canvas to initially create the spritesheet.
Then use context.drawImage(spritesheet,spriteX,spriteY,starWidth,starHeight) to display the star.
Spritesheet images can be drawn to the screen very quickly with very little overhead.
You might further optimize by breaking the spritesheet into individual star images.
Good luck on your project :)
1. Minimize operations, related to the DOM;
In the LINE 93 you are creating canvas:
this.scanvas = document.createElement('canvas');
You need only one canvas instead of this. Move canvas creation to the initialization step.
2. Use integer coordinates for canvas;
3. Use Object Pool design pattern to improve performance.
4. In for loops cache the length variable:
for(var i = 0; i < pxs.length; i++) {...
}
Better:
for(var i = 0, len = pxs.length; i < len; i++) {
...
}
Note: don't mix jquery with native js.
I'm writting about the mobile browser performance with HTML5 canvas. I'm trying to make a simple platform game (like super mario bros). I have a main character, two enemies and blocks imitating jumping platforms. Character and enemies are drawn by drawImage, block are drwn by fillRect (for now, later it will be also drawImage). Everything is animated (when character moves, the character X is added to blocks X and so on).
Now I'm trying to add some random coins.
First I created variable for Image
var coinB = new Image();
coinB.src = 'coin.png';
Next I'm creating array with objects with random X and Y:
var k;
for (k = 0; k <= 30; k++) {
coins.push({
x: Math.floor(Math.random() * 36 + 4) * 100,
y: Math.floor(Math.random() * 3 + 1) * 100,
width:25,
height:25
});
}
And after that I'm trying to select everything and draw:
var l;
/* left is the character X for the animation */
for (l = 0; l < coins.length; l++) {
ctx.drawImage(coinB, coins[l].x - left, coins[l].y, coins[l].width, coins[l].height);
}
Everything is in a function() that is in requestAnimFrame.
Unfortunately after that, game has about 30fps (from previously 60 fps without coins) on Mobile FireFox (Chrome Mobile 20-30 fps). So it's about half of fps with coins.
Is there a better way to import images and draw them? For example I do the new Image() for all thing (mainchar = new Image(), enemy = new Image(), coin = new Image()= ect), the same with .src. I assume it's not the best solution.
How should I do, to gain better performance (to lose less fps) ?
Thank you for help.
I have a similar experience; I have looked for tips and trick, but there are no magic ways to solve the performance problem.
The key to improving performances is reducing the calls to "drawImage" to the absolute minimum... keep in mind that it is the bottleneck of your process!
So, be sure to draw only what is currently visible (i.e. dont draw coins/blocks/background) that are out of the view).
For what concern images loading, I dont see any alternative to what you are currently doing.
The best you can do is using a unique file, containing all the images, and then using the right portion when you need it; this should reduce download times (1 larger files is better than many smaller files), but wont increase performances.
Hope this helped a little, have fun!
My demo is up here
You'll notice the zooming is quite choppy. The rotating is very static.
I'm looking to achieve similar results to Google's WebGL Globe.
At first I was using the standard OrbitControl.js file
but I wasn't liking the overall feel of it. So I started using this one which
includes some part about momentum and such.
I've tried embedding it but I had little luck.
// CONTROLS
cameraControls = new THREE.OrbitAndPanControls(camera, renderer.domElement);
cameraControls.target.set(0, 0, 0);
cameraControls.maxDistance = 610;
cameraControls.minDistance = 210;
cameraControls.userRotateSpeed = 500;
cameraControls.momentumDampingFactor = 8;
cameraControls.momentumScalingFactor = 0.005;
cameraControls.getMouseProjectionOnBall2 = cameraControls.getMouseProjectionOnBall;
cameraControls.getMouseProjectionOnBall = function(x, y){ return cameraControls.getMouseProjectionOnBall2.call(cameraControls, x, cameraControls.screen.height/2);}
Playing around with the numbers on the momentum lines hasn't helped much.
Is there something I'm not doing right or is this just a limitation of the script?
Are there any other scripts out there with a smoother feel than OrbitConrol.js?
Note: Changing the user rotating speed parameter does nothing.
Note2: I am basically trying to build this
Notice how smooth the rotating is. I don't want to use trackballcontrol.js because it doesn't limit the rotating angle like orbitcontrol.js
I have this piece of canvas animation that is exhibiting some weird characteristics:
http://jsbin.com/olasol/2/edit
I'm on the latest version of Chrome. I'm using Chrome's inbuilt FPS monitor (you can activate it by going to about:flags).
I have marked the line in the JavaScript section which I think is the potential culprit:
fallingctx.clear();
This line does nothing special. It calls a function which in-turn calls clearRect().
The "weird" things I notice are:
The clear(); function causes very noticeable FPS drop on my laptop (Core 2 Duo), but not on my desktop (i5 2500k).
Removing that line alone is sufficient to produce 60fps on my laptop as well. As expected, the canvas doesn't clear after each frame, but still, it produces stable 60fps.
The FPS drop happens only when my Chrome window is on the larger side! When I shrink the window and reload, it doesn't happen! (Is it more expensive to clear a larger rectangle?).
I tried replacing the clear() with a drawImage() of a full white JPEG to cover the canvas. The JavaScript is able to do 200 drawImage() executions each cycle for the smaller image particles (evident from the second point). However, when I add one single drawImage for the overall canvas, it lags again! (Make sure the output occupies the entire screen in order to reproduce the result.)
Why is all this happening? How do I fix it?
It really depends on the hardware, but think about what the invocation of clearRect has to do! Something essentially must zero-out a piece of memory large enough to handle the canvas contents. That can be costly. Think about how much memory has to hold RGBA at HD resolutions... That's over two million pixels of data, around 8 MB in bytes Admittedly, it's not all that much these days in general, but if there's any bandwidth or caching issues related to pushing memory to the video card or something you are doing 60 times a second... well, expect problems.
What I've heard often works is just to clear around where the image is formerly drawn. See http://jsbin.com/olasol/6/edit
I made the following changes for you.
for (var i=0; i< noOfDrops; ++i)
{
fallingctx.clearRect(
fallingDrops[i].x-1,
fallingDrops[i].y-1,
fallingDrops[i].image.width+2,
fallingDrops[i].image.height+2);
}
for (var i=0; i< noOfDrops; ++i)
{
fallingDrops[i].y += fallingDrops[i].speed; //Set the falling speed
fallingctx.drawImage (fallingDrops[i].image, fallingDrops[i].x, fallingDrops[i].y);
}
There's probably a good reason that I need to clearRect around where the image was rendered but a simple reason escapes me. (It is something to do with things being rendered not quite at the pixel specified... I forget exactly).
You also need to do something about the fact you are starting the render loop before the image is loaded (also in the jsbin) so I added
var imgSource = "http://lorempixel.com/20/20/sports/";
var imgObj = new Image();
and replaced superinit
function superinit()
{
imgObj.onload = function(){
flowerfallsetup();
requestAnimFrame(flowerfall);
}
imgObj.onerror = function (){
alert("could not load image");
}
imgObj.src = imgSource;
}
Edit: I forgot to mention because of the prior image setup, I did change the line in your flowerfallsetup :
fallingDr["image"] = imgObj;
There are many ways to handle the asynchronous loading of images, I just chose one that was easy for this example.
Edit: I have to confess, there might be a bit more to this. It works fine on desktop browsers, but on the iPhone, there are clipping issues. If I can figure out what's causing the problem I'll try to post an update.
I'm using the Canvas object with javascript. Just doing some tests to see how fast I can set pixels in a draw loop.
On mac, it works great in FF, safari, chrome. On windows, I get a flickering effect on FF and chrome. It looks like somehow the canvas implementation on windows is different than on mac for the different browsers? (not sure if that's true).
This is the basic code I'm using to do the drawing (taken from the article below - I've optimized the below to tighten the draw loop, it runs pretty smooth now):
var canvas = document.getElementById('myCanvasElt');
var ctx = canvas.getContext('2d');
var canvasData = ctx.getImageData(0, 0, canvas.width, canvas.height);
for (var x = 0; x < canvasData.width; x++) {
for (var y = 0; y < canvasData.height; y++) {
// Index of the pixel in the array
var idx = (x + y * canvas.width) * 4;
canvasData.data[idx + 0] = 0;
canvasData.data[idx + 1] = 255;
canvasData.data[idx + 2] = 0;
canvasData.data[idx + 3] = 255;
}
}
ctx.putImageData(canvasData, 0, 0);
again, browers on windows will flicker a bit. It looks like the canvas implementation is trying to clear the canvas to white before the next drawing operation takes place (this does not happen on mac). I'm wondering if there is a setting I can change in the Canvas object to modify that value (double-buffering, clear before draw, etc)?
This is the article I am using as reference:
http://hacks.mozilla.org/2009/06/pushing-pixels-with-canvas/
Thanks
I think it's fairly clear that browsers who implement the Canvas object use DIBS (device independent bitmaps). The fact that you have access to the pixelbuffer without having to lock the handle first is proof of this. And Direct2D has nothing to do with JS in a browser thats for sure. GDI is different since it uses DDBs (device dependent bitmaps, i.e allocated from video memory rather than conventional ram). All of this however has nothing to do with optimal JS rendering speed. I think writing the RGBA values as you do is probably the best way.
The crucial factor in the code above is the call to putImageData(). This is where browsers can differ in their implementation. Are you in fact writing directly to the DIB, and putImageData is simply a wrapper around InvalidateRect? Or are you in fact writing to a duplicate in memory, which in turn is copied into the canvas device context? If you use linux or mac then this is still a valid question. Although device contexts etc. are typically "windows" terms, most OS'es deal with handles or structures in pretty much the same way. But once again, we are at the mercy of the browser vendor.
I think the following can be said:
If you are drawing many pixels in one go, then writing directly to the pixelbuffer as you do is probably the best. It is faster to "bitblt" (copy) the pixelbuffer in one go after X number of operations. The reason for this is that the native graphics functions like FillRect also calls "invalidate rectangle" which tells the system that a portion if the screen needs a re-draw (refresh). So if you call 100 line commands, then 100 update's will be issued - slowing down the process. Unless (and this is the catch) you use the beginPath/EndPath methods as they should be used. Then it's a whole different ballgame.
It's here that the Begin/End path "system" comes into play, and also the Stroke/Outline commands. They allow you to execute X number of drawing operations within a single update. But a lot of people get this wrong and issue a redraw for each call to line/fillrect etc.
Also, have you tried creating an invisible canvas object, drawing to that, and then copying to a visible canvas? This could be faster (proper double-buffering).
The problem is with the way the browsers use the native graphics APIs on the different OSes. And even on the same OS, using different APIs (for example GDI vs. Direct2D in Windows) would also produce different results.