detecting supported opengl extensions

[almos]

Mesa supports frame buffer objects(this is where most cards will bail out I think) but not floating point textures?

In reply to my bugreport they wrote that:

The game uses GL_RGBA16F, which is a texture format from the extension GL_ARB_texture_float, that is not supported by Mesa.

Now I asked on IRC, and they don't support GL_ARB_texture_float on r600g either, so it's safe to assume that it's a global issue in Mesa.

BTW I was told that r3xx and r4xx cards bail out primarily because they cannot support dFdx/dFdy/fwidth calls.

I saw your committed fix. You didn't add the GL_ARB_shader_texture_lod check, which is not advertized by Mesa, and I was told that r3xx/r4xx cannot support it.