I am doing some pre-production on a project that requires drawing on a 3d canvas, which I think flash is the best way to go. But there is a chance down the line that this client might want the site to show up on the ipad, iphone or other mobile devices that don't support flash.
So I was playing with the idea of doing everything in html and javascript except for the actual drawing/3D area. Almost like using flash as the element. I think html5 is too premature to start using this, but might be beneficial down the line. Chances are I will just go the entire flash route, but I thought it would be interesting to try.
Anyway, my question is pretty top level. 1) how hard would it be to drag an object from an html page using javascript, and dropping it into the flashplayer. And then manipulating it from there.
Are there any examples out there that have tried to do this?
Communication between Flash and an HTML page requires the use of ExternalInterface. That's a good place to start. These guys seem to have figured out some of the details.
As far as the iPad and iPhone are concerned, Flash just ain't gonna happen.
However, I don't think it's fair to say HTML5 is "too premature". Lots of people are doing lots of cool things with the canvas element. You could too. :)
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So sorry that I'm so very newbie, and have googled only to find the same result again and again, till desperately I decided to ask here...
So, I need to make a webpage that can detect/reading hand gesture. At first, I was so very lost in what to do, but then this and that, I've found these questions:
Using webcam to track hand gestures
Generating events for gesture-controlled websites
How to detect hand gesture in live webcam using javascript?
hand gesture recognition with camera video in actionscript
And after surfed things I found there, then I (thought that I) got that it could be done using Javascript or Flash ActionSript, and have seen some of the examples for both. While I (thought that I) understood that people did it through Javascript by implementing algorithm for image processing and its friends, actually I'm kinda lost at how Flash did that. I found the common usage of gesture using Flash is in 'webcam game', and then I found these tutorial:
Webcam Motion Detection: Using the BitmapData API in Flash 8
Np's Webcam Game Tutorial
While I (thought that I) kinda get how the first one did it, I'm lost at how the second working out his collision detection... And I don't really understand why, while mostly the Javascript I found has pretty good documentation, so hard to find something like that for Flash ActionScript, and the one I found is kinda old (the first tutorial said it's created at 2005, and the second uploaded in 2007). I would just use Javascript because of those things, but then this Incubator Quasimondo Minority Cube is really cool, and I haven't found an implementation in that level for Javascript...
Thus all of it leads me to a question, roughly:
how hand gesture detection usually implemented in Flash? like, in webcame games?
does those implementation really 'recognize' it's a hand? or does it just execute anything that moves?
what support Flash/ActionScript have for detecting gesture? Like Camera.activityLevel property, is there another property or library?
I'm so sorry for my lack of knowledge...
All the examples I've seen are simply using the 'image recognition method'. Thus the results are not solid and sometimes there won't be anything to detect at all. That's why Eugene created augmented reality framework, but you need a marker in order to use it. He did some experiments without markers, but I cannot find any of them now, sorry.
I've used Kinect for gestures and it works pretty well, and it has AIR sdk.. Maybe you should give it a try :)
I think there are two diffrent solutions for the problem:
1) First the solution shown by aves Engine, which renders the whole game with html elements and external stylesheets e.g. CSS3 transfomations. Pro's are that the event-handling is much easier when working with div's than by rendering on canvas.
2) Like isogenicengine.com shows you could render the game on html5 canvas element. Mabye that's the better solution, because rendering on canvas is the way that millions of 2D-games were written before and in future the industry will optimize the drawing methods e.g. with hardware acceleration. At the moment the contra is that rendering on canvas is slow if you would like to render in fullscreen. If you would like to render only in a specific area of 200x200px that's okay, but in fullscreen you get stuck with a framerate of 10fps.
What do you think is the better way to create a game for the web?
Thanks for your opinion!
PS: If you have some articles about the topic please paste some links
I don't think it's a clear one size fits all kind of thing. I really think it depends on what you want to do with your game.
If you are doing a lot of vector graphic manipulation, perhaps canvas is a better choice vs engine like aves. For tiled based, maybe aves will work better.
You can render fast on fullscreen canvas if you're clever about only re-rendering dirty regions. But if your whole canvas needs to change every frame this obviously isn't going to help much.
I've spent alot of time recently looking into this issue and my conclusion is pretty simple.
Use HTML Elements, lets say that HTML5 actually makes progress and in one year the major browser support it. How long does it then take to get the general user base of the web on the latest browser (IE6 still has a choke hold in some sectors). So making the game available to as many people as possible is key! (In my mind anyways)
If however, your looking to learn and develop, go with canvas.
What is the best cross-browser way to get a flat mouse coordinate input data and simple callback for mouse events for my rectangular game area on my web page, even when it has loads of larger and smaller images and text string overlaid haphazard onto it?
And what is the best way to insert or remove a text string or semi-transparent image overlay at an arbitrary location (and Z order, specified relative to existing objects) in a board game rectangle with cross-browser DHTML?
And how can I stop the user selecting part or all of my montage of images (I just want them to interact with it as if it was Flash), and can I stop the right click menus coming up in IE, FF etc?
I want to do this without Flash because I want something that will work both on desktops and on iPhone and potentially other mobile platforms too.
I appreciate there are serious limitations (eg less image scaling capabilities, not vector, no rotation capability) to what I can do if I'm not using Flash but I'm very interested to know what capabilities are available.
Are there perhaps any frameworks available to make it easier than coding from scratch?
Would J/Query be a good match for some of the requirements? What else do I need?
I would recommend Google Web Toolkit. It lets you program in Java, which gives you all the type-safety and nice IDE functionality that Java entails, but compiles to Javascript so that you can just run it in a browser. It also does a ton of optimization and supports tons of features.
jQuery is excellent at doing this. I used jQuery's UI and Ajax functionality to implement the frontend for a game of chess.
I made it a little easier by creating an 8-by-8 table with unique div names for each tile, so Javascript can access them by getting the elements by id. If you can't create something like that, you do have the option of placing elements anywhere on the page (either absolute or relative to a given element). You can also easily change the z-index, including when the use is dragging a piece or when they have dropped it.
As far as disable right click and item selection goes, that's something that I didn't figure out how to do. You might want to take a look at some other Ajax games like Grand Strategy, which are much more polished than my experiment and may have figured out how to do this.
There are two main APIs for working with arbitrary drawing and positioning on the web, Canvas and SVG.
Take a look at Chrome Canvas Experiments and the Raphael Javascript toolkit to see some examples and Javascript abstractions.
The key is element.style.position = 'absolute'. To illustrate just what's possible here's how far I've managed to push javascript (and from scratch at that!):
http://slebetman.110mb.com/tank3.html - RTS in DOM! Click on units/squads then click somewhere else to tell them where to go. You can control both sides.
I'm doing some animations and I want to implement something like this on the web. I was thinking that the HTML canvas can do this kind of job. Because I can scale part of an image. I just need the algorithm to actually make it work.
The effect is elastic, if the window is small, the greater the elasticity of the window when you restore it. I was thinking that I can make this work in web images.. if the user click the image it will scale with this kind of effect, not the boring way of scaling.
This is ubuntu, I know that we can look at the source code maybe to see how it actually implements the animation. But I dont know where to find it. Or i don't even understand codes written in linux because I just understand php, javascript. Basically I'm not a software developer, My core expertise is in web development.
http://www.youtube.com/watch?v=hgQP-aFragQ
I believe your best bet is having a look at John Resig's Processing.js.
Processing is a animation language for Java; John has ported it to the browser using canvas.
Your not going to find a web based solution that is going to do this for you. If you need something like this done it will have to be in flash or some other application (Lenni mentioned Java) that runs in a separate media box embedded in a web page.
People don't want big flashy animations, seeing something that is 'boring' is much better if it becomes more usable.
First up - I don't know the actual algorithm they use here.
However, I'd attack this by creating a grid of points (say 10x10), each point attached to it's neighbors by damped springs. It might be worth anchoring the edge/corner points to the screen with springs too.
By deforming the grid (stretching and compressing the springs) and then modeling the spring responses, you'd get some interesting effects like those shown. You might then be able to record the patterns so that the points can follow a pre-computed path for faster animation if your animations are predictable.
Then you need to work out how to split the image and map it onto the grid. The splitting may be better done once on the server, but the client can do it if you use canvas.
svg & vml is a possibility - they'll work without plugins and are similar enough to code for, but I don't think you'll get correct enough image deformation. However, you can scale and rotate with impunity (and quickly) so if you just anchor 2 cell image points to the grid rather than all 4, you'll get an interesting animation - not quite like the video, but pretty good.
As for how to model damped springs, you'll need to keep track of the mass of each point (how heavy it is), how much force the spring is exerting on each point (scalar of how compressed/stretched it is and it's vector) and a damping force on the points (resistive force to the square of the velocity of the point).
It's physics modeling, to be sure, but quite possible.
The response may well be slow. Especially on IE. Canvas needs a plug-in on IE, so if you use canvas, IE folk wont see it. SVG works on almost everything except IE, but it does have VML which is similar. http://raphaeljs.com/ is a library that uses whatever's available. This will be a challenge to tune up :)
However you do this, it will always look best in chrome, the V8 javascript engine outstrips everything else for this kind of work. IE has the slowest javascript engine.
I have an idea for a website which involves a canvas area which has no limit to its size. Basically you would be able to add items to the canvas (notes, photos whatever really). You would then be able to drag the canvas which would move those items along with the canvas until they disappear of screen. If you dragged the canvas back the other way they would appear again.
Question:
Which would be the best suited to this type of thing, Flash or Javacsript?
My main worries are the speed at which javascript/ flash could handle moving multiple items around on screen in the way discribed. Which language would handle better for a user on a slow machine.
UPDATE:
Thanks for your opnions guys, but to clarify what are the benefits of canvas over straight jQuery DOM manipulation? or visa versa. I've never used canvas before.
I don't think this is a question that will get you an objective answer - Flash developers will tell you Flash is better, web developers will say JavaScript. Trying to remain objective, I'd say that both technologies are suitable for what you describe, but have different advantages.
Flash will definitely render faster, even on slow machines, and is much richer graphically.
JavaScript is more accessible and works on a greater number of devices. Use a good JS framework though.
My initial thought would be to go with Javascript - if it's good enough for Google Maps, it's probably good enough for your app too.
Do you need to use canvas, what you're describing could be done with just javascript and the DOM. It would perform perfectly well unless there are a huge number of elements and it would be cross-browser compatible. For canvas you would require exCanvas to support IE which can sometimes slow things down.
The best way would surely be Javascript. And I would even say that you should reconsider the use of canvas. It sounds like it could be done in pure DHTML. In that way you wouldn't lose support for IE.
Consider using one of the javascript frameworks; Prototype or jQuery come to mind. It will ease your coding immensely. Given the development in javascript-engine performance (next versions of Webkit (Squirrelfish Extreme) and Mozilla (TraceMonkey) will be lightning fast) the worries about performance may be moot.
Also if you decide that you can't do it without canvas consider using John Resig's processing.js.
I'd say go with flash (or DOM if you don't need the extra punch). Here's my reasoning:
You can do cool transformations with canvas (skewing, rotations, gradient fade-ins in images, reflection effects, etc) that you can't with DOM. The downside is that doing these cool things is math heavy.
Canvas doesn't work in IE. IE's equivalent (VML) apparently has a root-access security hole.
The DOM has been around for longer than canvas and since it's more widely used (and depended upon), it's more optimized and polished than canvas.
The Flash community has a lot of good free components available that may already do what exactly you want.
Flash and DOM have a lot of good documentation and tutorials, canvas not so much.
Flash can do pretty much everything that the DOM and canvas can, plus audio, video and grabbing input from your web cam.