java, gpu and the web

Newbie & Debugging Questions
#1

Hi,

My question basically deals with the best approach to doing a fluid sim on the web using the GPU so that web users can interact with it. I currently have a fluid sim running on the gpu using openGL and GLSL. Its a multi pass approach using framebuffers to capture data from the GPU and feed it into the next pass as input. I have been doing some research, and have read about jogl, javaCL, processing, and webGL. I'm looking for some guidance on what would be the best approach (mostly in terms of performance). I need to be able to use the gpu for acceleration purposes, and it would be great to be able to leverage some of my existing code. My concern with webGL is it is so new and is only in preview builds of browsers. I tried using processing, but there aren't many resources out there for getting help. I appreciate any responses. Thanks,

Patrick

#2

Whats the problem with just using Java + OpenGL (with either LWJGL or JOGL as binding)? Most people have java, and all the user has to do is to accept a confirmation dialog. WebGL is still somewhat of a prototype rather than a functional product, so I would not recommend using it.
From my experience Java is the best platform on the web for hardware accelerated 3D.

#3

bienator may answer you… Use JOGL and JOCL, it works just fine, you should have a look at Michael’s demos.

#4

ok cool, i’ll do that, thanks!

#5

not so fast :wink: web + OpenCL is currently a bit risky. Drivers are not yet very stable especially if you want buffer sharing with GL.

At the end it really depends what you want to do if you say “fluid sim”.
2D? use plain java and a handfull threads.
3D+focusing on pseudo-realistic graphical effects? OpenGL + GLSL (maybe OpenCL if you want to be cool, look at Apples demos)
3D+physical simulation of fluids, forget anything webgl except you want to render on the server :wink:
realtime or not…?

#6

There are also no plans for WebGL to be implemented in IE, and it’s only supported in the nightly builds of FireFox, Chrome and Safari. If you use WebGL then practically no one will be able to run your app.

#7

Hi bienator,

I will be doing 2d. I'm using the lattice boltzmann method which scales well on the gpu. What do you guys think of wljgl? My concern with threads is it won't allow the parallel processing that the gpu does.
#8

you can use LWJGL for the job too. Both JOGL and LWJGL expose GLSL. And shaders are the parallelization vehicle what you are asking for. Although there were initially designed for graphics exclusively, they are sometimes abused for general purpose algorithms (esp. before CUDA, OpenCL etc. was available).

#9

Also, more people will be able to run a shader version than OpenCL, et al. As an example, on one of my machines I’ve a DX10 Nvidia card, update-to-date drivers and Nvidia’s OpenCL…it no worky.

#10

Right now OpenCL probably won’t work on many machines, since it requires specialized drivers and/or modifications.
See this page: http://www.geeks3d.com/20091221/how-to-enable-opencl-support-on-nvidia-and-amd-platforms/
I do not recommend relying heavily on OpenCL unless it becomes standard across all machines and gpus.

#11

thanks for all the info, I’m trying out lwjgl

#12

Why not giving a try with JOGL? ??? LWJGL has no interoperabily with OpenCL as far as I know.

#13

Er, how can it not interoperate?

Cas :slight_smile:

#14

I was thinking about this :

/**
     * The cl_mem that has the contents of the VBO
     */
    private cl_mem vboMem;

// Create the vertex buffer object
        int buffer[] = new int[1];
        gl.glGenBuffers(1, IntBuffer.wrap(buffer));
        vertexBufferObject = buffer[0];

if (GL_INTEROP)
        {
            // Create OpenCL buffer from GL VBO
            vboMem = clCreateFromGLBuffer(context, CL_MEM_WRITE_ONLY,
                vertexBufferObject, null);
        }

but finally, you’re right, it uses plain OpenGL, it should work with LWJGL too.