iluGammaCorrect

[malytomas]

Hi,
I have looked at this code:

DevIL/DevIL/src-ILU/src/ilu_filter.cpp

Line 935 in e34284a

ILboolean ILAPIENTRY iluGammaCorrect(ILfloat Gamma)

As I understand it, there are two issues with it.

1. With bpc (bytes per channel) > 1 the algorithm throws away any higher precision data and outputs just 256 different levels. It should properly compute the power instead of using the precomputed table. (Or precompute higher-precision table depending on the image resolution.)

2. The algorithm applies to alpha channel too. Since Devil was designed to work well with OpenGL, I would assume that it would behave similar to sRGB textures, which do NOT alter the alpha channel.
   https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glTexImage2D.xhtml
   Or is alpha channel stored separately? I am not that much familiar with Devil internals.