r_alternateBrightness

[fromhell]

Basically, a technique to simulate the r_overbrightBits screen color adjusting by having a GL_SRC_ALPHA GL_DST_COLOR white plane overlay on the rendering output entirely (even above the console), using overbrightbits' brightness compensation in effect for it, having the brightness cvar adjust its alpha.

PROS:
- Do it in a window!
- Do it on X!!!!!!!!!!!!!!!
- no combines!

CONS:
- it blends. could be expensive on REALLY OLD hardware or even software GL rasterizers

[andrewj]

That'll just make everything whiter (e.g. black becomes #808080).

If GL_DST_COLOR could be used as the source (i.e. as Cs in the C = CsS + CdD equation) then you'd be adding the framebuffer into itself and getting the same effect as overbrightbits=1, however I'm fairly sure (having checked the OpenGL 1.3 specs) that GL_DST_COLOR is not supported there.