i have a problem using an textures alpha value as a mask for rendering a terrain chunk. GL seems to ignore the texture and uses vertex alpha instead. Although texture targets are enabled. I cannot see anything wrong in the tex_env_combine setup.
No gl errors are reported. The setup is here: http://www.eisscholle.de/TextureMask.cpp
The masks texture format is GL_ALPHA and GL_ALPHA8 internally.
Thank you very much for any hints.