In this case only diffuseMatColor really matters, other values are constant.
It improves performance on GLES renderer and it's also noticeably faster for GL on desktop.
For example:
- fps increased for me from 60 to 69 on Hacienda with intel HD 4000
- from 43 to 49 on lighthouse
There is much less difference on nvidia graphics card, but still it gives small performance improvement.
- Don't use BGRA format at all. It doesn't work with non-typical cases (i.e. with srgb or compressed textures) and also casues artifacts on some android devices. I kept the extension in central settings, but it probably won't be used.
- Use sRGB texture format when advanced lighting is enabled. This makes it closer to the original OpenGL renderer and also avoids to have even more #ifdef's for sRGB conversions.
- Keep RGBA textures for non-advanced lighting to make it simpler.
Now advanced lighting in GLES looks almost the same as in OpenGL 3.x (without shadows/GI)
It's a bit ugly solution because we should handle it properly in one place and not add another sRGB correction... But it's already working solution and it doesn't affect the OpenGL renderer, so we can use it until better fix will be done.
Now the GLES renderer looks almost the same as the original OpenGL 3.x one :)
It allows to enable it easily in GLES renderer. And we check if this extension is available anyway because it's needed for shadows, so we can use it for other shaders too.
This function was used by Cand for his OpenGL 2.1 renderer. The round function is available since GLSL 1.3 (OpenGL 3.0), so there is no need to override it.
If it will be needed in future, I suggest to change the name to round_stk or something similar.
