Coming from the backbone side of web development we are trying to find a solution for a request to add visual and sound effects to our task management web application.
For starters - we are looking for a way to create an exploding stars effect like you see in games.
Can this be done with HTML5 canvas?
Should we use flash?
Any ideas how to start?
By now, just about anything Flash can do visually can be done by the HTML5 canvas on modern browsers.
For a 'star burst' visual effect, it sounds like a simple matter of creating a random array of objects that move away in random pre-set directions every time the canvas updates.
Example: http://jsfiddle.net/amDAW/ (click on the canvas to create a starburst)
As for sounds, this isn't handled in the canvas, but rather either the Audio tag or the fairly new WebAudio API. If you go with the former (more browser support), your biggest concern will be with resource preloading, but there are some helper libraries that can abstract this away (shameless advertising: https://github.com/jsweeneydev/ResourceLoader).
Related
I'm trying to apply filters to full-hd videos in javascript using pixel manipulation.
I created a demo using hidden canvases, web workers and transferables:
http://lab.jure.it/ww/ww.html
The result is that using web workers the browser's tab crashes in a short time, and the video has very low performances (~5fps).
If you select "Web workers: 0" ww are not used, the performance is better (~15fps) and the tab doesn't crash.
What can i do about it? The goal is to obtain a good framerate (~30fps) avoiding SVG or CSS filters.
Thanks.
Looping through all pixels and converting them on CPU is not a good idea. That's what GPUs are for. In past, that would mean you have to use something nasty, like Flash.
Fortunately, new technologies are emerging and graphic acceleration is available in most popular browsers. It's called WebGL and it allows you to make use of graphic card for these things.
Unless you want to learn all the internal secrets of WebGL (it's quite complicated), I advise you to use PixiJS framework, which is designed for 2D animation.
You can see their filtering demo here: http://www.goodboydigital.com/pixijs/examples/15/indexAll.html
More demos and examples are here: https://pixijs.github.io/examples/#/basics/basic.js
I am planning on creating a real-time multiplayer platformer game in HTML5 using javascript. After searching about 4 hours on the webs, i couldn't find an up-to-date answer on the eternal question: rendering my game with DOM will be faster than rendering it inside a canvas? The game will be the whole document. 2/4 players will be jumping on the map and will shoot at each other, bombs will explode. So? What will it be. I remember I made 2 years ago a draw application with DOM and it worked kinda smoothly, but i guess canvas speed is better nowadays? Thank you guys.
P.S. I think of using Dart too.
I use canvas, and would say to do the same since it's a direct drawing mode. However, you should absolutely make sure it is forced into hardware acceleration wherever possible. You do this by setting the style of the <canvas> element into transform:translateZ(0); (or different browser interpretations of that, e.g. -webkit-transform:translateZ(0);). Manipulating the DOM can be slow now that canvas is closer and closer to native code, especially with simple methods to get the most performance out of it.
My games seem to do pretty well on different platforms with this - not universally well on every single platform (older Android OSes lag, but their JS & browser rendering engines weren't that fast to begin with), but quite well on many platforms.
Canvas is the best choice for the type of game you are describing, but some DOM elements are still very useful even using canvas, for example, asking the player's name, or creating a menú or profile section inside the game. You can render a div with absolute position on top of your canvas when you need to display DOM elements, and do all the "game stuff" like drawing and animate sprites in the canvas element.
The reason why Canvas is the best choice is simple. I'm pretty sure that you can't or it would be really hard to do things like this without the canvas element:
http://galloman.github.io/ss2d/samples/skeletons2.html
More at: http://ss2d.wordpress.com/support/
I'm looking for a simple JavaScript library or framework to create interactive 2D animations in the browser. (Excuse the buzzword in the title, but I'm not set on any particular rendering technology like Canvas or SVG.)
This should make it simple to draw and animate arbitrary (though not very sophisticated) shapes on a canvas screen and allow users to select and move these shapes as objects (kind of like a very basic RTS game engine).
Ideally, the following features should be supported (directly or indirectly; I'd implement it myself if necessary):
panning
zooming
fisheye partial zooming
box selection (selecting multiple objects by drawing a box around them)
Not being familiar with such things yet, I find it tricky to research what's out there (e.g. regarding search terms). Also, I have no illusions about some magical package that doesn't require any effort on my part - indeed, I'd prefer simple and readable libraries so I can learn about the basics by reading the source.
If you like simple libraries, perhaps take a look at GameJS. It claims to be "a thin library on top of the HTML5 canvas element." It's a port of PyGame to JavaScript, which in my experience is a fairly nice abstraction layer that at the same time doesn't overdo it.
If that doesn't cut it, have a look at this list of JS game (and animation) engines.
You probably did make a search and found dozens of js game engines. I will just narrow it down for you. It is impossible to just spit out one single js game engine. Also, you might find some to be more appropriate than others based on the type of game you want to make. So here they are
LimeJS
Impact
Crafty
I want to create not complex interactive web application. It has some pinboard and user can create many simple objects on this pinboard (e.g. many small circles). After this user can:
move these objects
delete some of them or create new ones
make multiple selection and move/rotate elements of selected group
place members of the selected group in some special order (grid, line, circle, etc)
Zoom in/out pinboard
I think that I can use Flash/Flex or JavaScript/SVG/VML for this purpose. Disadvantage of Flash is that user must have plugin. Minus of JS/SVG/VML is that there aren't such powerfull developing tools as in Flash case, but if we use some library (like http://raphaeljs.com/) application won't require flash plug-in.
I'm finding right tool for this aim. So give me some recommendations, please. Thanks in advance.
I believe that you can achieve your goals without Flash using HTML(5), JavaScript and not the least the Canvas element present in HTML5.
Bottomline is, unless you today require your application to animate a lot of objects with framerates approaching three digits, the above should suffice fine and will also pair you with a prospective Web development platform. I am often sceptical of the new stuff, but HTML5 and Canvas are fairly standardized, patent-free and are being actively adopted.
The only benefit of going with Flash that I can think of is being backed by a rich API that does 2D as well as 3D, and the fact that you can later port your ActionScript code to say, JavaScript when you finally decide to go with HTML+JavaScript instead. Aside from having to perhaps rewrite part of your drawing stack, your ActionScript code will require minimal (syntactic mostly) changes.
I would still advise you to go with my first suggestion, unless you need live (camera) video publishing, 3D, sound editing and few features not available easily outside Flash Player. Which I don't think you will need.
You might want to have a look at existing similar projects, such as SVG Edit (MIT license).
Kind of a dilemma here. I am making a mobile version of a website, that has some interactive things more specifically I have this object in 3D that you can spin, I was using papervision in Flash but now I need to do this differently since there is no flash in mobile and I feel I am on thin ice.
I was thinking of exporting a 360 degree spin # 30 FPS using a PNG sequence with alpha channel, and then simply stiching them together into a sprite, then using this as a background in CSS and using background-position to then "simulate" an animation.
That or simply switch source image very rapidly, or somehow using "canvas" maybe, the thing is I am not sure if this will produce completely subpar performance? I mean switching the background-position or image source file # 30 FPS is that even possible? Would it be smooth, or is this simply something that is not feasible todo yet? Keep in mind it's just one single 3D object that needs to spin based on user input, not any other interactive elements.
So is sprite the way togo or canvas or something cool I havent even heard of? Thanks everyone in advance!
If I was making a mobile version of a website, I would strip it of most of the graphics and definitely of all the animated gifs, flash, etc. -- people using mobile phones for browsing the web are usually not after the multimedia experience -- they just need some information quickly and use a suboptimal device with poor bandwidth and even worse display and performance to get it. Don't make it even harder for them.
On the other hand, I found that using a background image with all the frames of animation in it, and manipulating the background-position from javascript is a fine way of making small animated sprites, for example for a simple javascript game for mobile phones :)