Hi, if you take a look at the latest movie of this new upcoming flight simulator ( www.lo-mac.com ), you will see a very interesting heat effect. Can you tell me, in your opinion, how did they achieve it ?
Render-to-texture, then deform in screen-space.
You can even use the nvidia texture shaders using the offset texture operation along with some way to generate the offset how ever much you want. I guess some noise function would work fine. Actually you don’t have to use texture shaders, it can be done on the CPU but it would be faster on the GPU.
This can be done on an ATI card too but using their own extensions of course. I don’t exactly know which ones since I don’t have an ATI card but I’m sure it wouldn’t be hard to figure out.
Texture-dependant read is possible in GeForce3+ hardware using the NV_texture_shader extension, and in ATi Radeon 7000+ hardware using the ATI_envmap_bumpmap extension.
But for an effect in screen-space you don’t really need those fancy extensions.