The fog mode is compleatly a vertex parameter is it not? I can change my glFogf parameters without affecting my end result at all when arb_vertex_program is enabled. All the OpenGL spec to my knowledge says is If enabled, fog blends a fog color with a rasterized fragment’s post-texturing color
using a blending factor f. That blending factor is given by result.fogcoord.x in ARBVP.
Now if i tell glFog that my color is a certain color why is my regcomb final combiner doing the correct blend of fogcol,finalcol, and fogfactor, whereas opengl is doing something different.
I ask because the problem doesnt seem as simple as the fogcoord isnt being generated correctly. In both cases my entire scene is bicolored one correct color my fog color for the regcomb objects, and two some seemingly random color for all glFogged objects. I deduce that in both cases my fogCoord is correctly set to 1 since all textures are bled out to the fog color.
When you write “For a fogcoord of 1 with a fogcolor of 243,220,197, register combiners give me 243,220,197 but normal glFog gives me 211,141,90.”, what do you mean by “gives me” ? How do you query the value ?
Sorry bout all the hassle fellows. I discovered the problem and as you can imagine it was pretty simple, that section of code was going through extra blending passes, to which fog was also enabled. Thanks for all the interest… I spend way to much time looking for something complicated to be the solution.