Those who know me know I used to do quite abit of development in c# using Microsoft’s XNA platform.

Well I like to check back in every now and then with some of the big players in the community to see what’s going on.

One of those players is Catalin Zima, who is famous for producing many great shader and effect samples.

One of Catalin’s reccent project particularly caught my eye however as I had tried to tackle the same problem several years ago when I was in my final year of university. That is, Dynamic 2D Shadows Calculated on the GPU (http://mikecann.co.uk/university-projects/shadowshader-in-rendermonkey/)

Catalin’s approach to the problem is far more elegant that my brute force iterative approach. He uses a clever technique of distorting the desired casting image about the light in such a way as not to require iterative pixel lookups.

If you are interested in the more details in the technique I encourage you to check it out over on Catalin’s blog: http://www.catalinzima.com/2010/07/my-technique-for-the-shader-based-dynamic-2d-shadows/

http://www.mikecann.co.uk/?p=163
httpvh://www.youtube.com/watch?v=vxrg1YavBIg

http://www.mikecann.co.uk/?p=169
httpvh://www.youtube.com/watch?v=3wdIiCCAb9U

I have another reason for these old re-posts, something a little more flash orientated.. Stay tuned for more info

Basically it takes a texture and picks out pixel colours from the texture and maps it onto a large vertex buffer which then is used as the input to my Vetex Texture particle system.

I have made a few adjustments to the way the vertex texture system works, now each particle has its own centre of gravity that it revolves about.

You can grab the new binary: http://www.mikecann.co.uk/Work/XNAGPUParticles_v1-1.zip

As per last time if you wish to see the source please dont hestitate to email me.

The project is a continuation based on work from before Christmas and is an experiment into state preserving particle systems. I started out with examining the basic particle systems such as a static system and one that updates on the CPU. I then moved onto more advanced systems such as the GPU based system described by Lance Latta and others. I soon discovered however that XNA doesn’t support “uber buffers” and as such had to invent a new solution using vertex textures. The result is a particle system written in XNA that is able to update and render 1,000,000 particles at about 22 frames a second with 4 forces.

To view this demo you first need to have the XNA runtimes. If you dont have those just go HERE.

Once installed you can grab the binary for this project http://www.mikecann.co.uk/Work/XNAGPUParticles.zip

If you are interested in seeing the source code for this project, just drop me an email: mike.cann@gmail.com

Oh also, the written report for this can be found http://www.mikecann.co.uk/Work/GPUParticles2003.doc

So i decided to have a go and this was the outcome. In the end however its too slow to be used in the game but serves as a usfull learning tool when the hardware catches up.

To view this you will need to download RenderMonkey.

Download: ShadowShader.zip

This is my first little dabble with the excellent shader creation tool, RenderMonkey. To view this you will need to download the free app.

This was acually a peice of work for one of my modules so the .zip file contains the written report too.

Download: Particles01.zip