Thanks a lot, jansoft.
That was easier than I expected.

Is there an equally easy way to draw a texture onto another texture?
I managed to write a pixel-by-pixel routine (two address pointers) but it is quite slow compared to the texture-drawing routines of powerdraw (factor 10).
Can one draw textures onto each other using DX or D3D accelerated routines?

thanks,
strangerranger