the manual doesn't say so; however, I get error message saying something about video device not being open if I try to execute bmap_to_alpha before the first call to engine_frame.

the funny thing is it looks like it actually worked even though I got the error???

so must the first frame be executed before this function can be called? if so the manual should state that.

I think this is because you need to have initialized DirectX before you can using DirectX functions. Most engine functions need DirectX, bitmap functions for certain.

Its the same as if you would use entity functions without having created an entity before.