bug in GL_EXT_blend_color with 3Dlabs cards ?

Hi, I’m working on Wildcat 4110 support for an OpenGL renderer. Since that card doesn’t support GL_ARB_texture_env_combine, I’m using GL_EXT_blend_color for some effects.

GL_EXT_blend_color works fine with nVidia and ATI drivers, but doesn’t work at all with 3Dlabs card (latest drivers for XP)

I changed a nehe tutorial to show the problem : http://oplayez.free.fr/BlendColorBug.zip

here is some screenshots : http://oplayez.free.fr/BlendColornVidia.png http://oplayez.free.fr/BlendColorWildcat4110.png

Can you have a look to the code and confirm me that it’s a driver bug or not ?