Diffuse maps

OpenGL OpenGL: Advanced Coding
1

Hi All,

What are the diffuse maps below? Where can I learn more? Have they something to do with occlusion culling? Are they generated on the fly or something the 3D artist needs to paint manually?

Thanks,

Alberto

2

Done completely automatically. Well, maybe the texture atlas coordinates unwrapping is done by hand or semi-assisted.
Project texels in texcoord space into 3D world space, compute diffuse value with your (potentially offline) renderer (which can use occlusion or raytracing for this), store in on texture. When done, uninitialized parts of the texture are ‘colonized’ by nearby values, to avoid bleeding on mipmaps.

3

Therefore, if we need more realistic real-time rendering we would need:

  1. to compute this texture for each mechanical part face
  2. to nest all of them on a square texture
  3. modulate the face diffuse color with the texture color

Right?

Thanks,

Alberto

4

Yes, this is also called ‘baking’ :
http://wiki.blender.org/index.php/Doc:Manual/Render/Bake
http://www.katsbits.com/tutorials/blender/blender-2.5-baking-ambient-occlusion_adv.php

All sort of stuff can be baked, be it ambient occlusion, normals from a highly detailed object to a coarse mesh, static cast shadows, a complex procedural material, etc.

“All programming is an exercise in caching.” - Terje Mathisen

5

Thanks sooo much!