opengl.cpp
find this : Code:
void APIENTRY pglBegin

somewhere in body add following:
Code:
if(cvar.fullbright && mode != GL_TRIANGLES && mode != GL_TRIANGLE_STRIP && mode != GL_TRIANGLE_FAN && mode != GL_QUADS )
    {
      glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
      glDisable(GL_TEXTURE_2D);
    }

Register your cvars!