Transform feedback (GL)/ stream output (DX10+)

[Mel]

Two names, the same idea, which consists in that the output of a vertex/geometry shader can be stored in a buffer so it can be reused later, the utility of this is to store meshes after complex transforms done in the GPU, so they can be reused without being processed again. Shader skinned models get skinned only once, but rendered many times, for multipass shadow map techniques this is an advantage, and other meshes can benefit of this.

Thoughts? ideas?

http://www.opengl.org/wiki/Transform_Feedback
http://msdn.microsoft.com/en-us/library ... 85%29.aspx

[Granyte]

the dx10 driver already suport this although i think the feature has been hidden when it got integrated with the trunk it's still there and could be exposed

on the though side it's a real nice feature and hopefully it will be included with irrlicht it would make my current main project much easier

[Mel]

But, besides the skinned thing i said, what else does this thing work for?

[Granyte]

is allows for meshes to be constructed entirely on the gpu from scratch and can also be used for particle entirely handeled on the gpu

[Nadro]

For example it is useful for Radeon HD2-4k tesselation system. On these cards you have an access to tesselation oparations from vertex shader, so eg. skinning + tesselation don't work efficient, you can't also use geometry shaders together with tesselation extension. You can easy solve these problems thanks to transform feedback, just do eg. skinning and put geometry in the output buffer and in next step do tesselation.

This is really nice feature, it should be available in Irrlicht v2.0

[hendu]

Complicated particles is a good use. For example snow that accumulates on ground.