OpenGL - normal maps

Code samples derived from work by Joey de Vries, @joeydevries, author of learnopengl.com/
All code samples, unless explicitly stated otherwise, are licensed under the terms of the CC BY-NC 4.0 license as published by Creative Commons, either version 4 of the License, or (at your option) any later version.

[@abogadojon]

No one does it better than Brian "The Brain" Will. Sincere thanks to you.

[@kadealicious]

Your OpenGL videos are extremely informative and well done. Thank you!

[@Vagelis_Prokopiou]

Thanks Brian. Really informative.

[@andrewh111]

For the smoothed/non-orthogonal normals/tangents I think re-orthogonising them in the fragment shader should work.

[@briantwill]

I've seen some suggest doing so in the vertex shader too, but either way I'm skeptical about the correctness. I suppose it depends on what the authors of the models and normal maps expect to see (but then you have the problem of stretching in animation, in which case in may not be possible to visually check all possible states).

[@glowiever]

I did this for my animated character, reorthogonalizing in vertex shader, and renormalizing in fragment shader. as long as the mesh do not become degenerate it works quite fine.