Can OpenGL render to DirectDraw surface ?

Can OpenGL render to DirectDraw surface ?

Post by THX 113 » Sat, 27 Jun 1998 04:00:00



Thx jrmac and tplanie2 for your responses!

It looks like I can set them up together on some hardware... but on my
newer system this is a non issue because I am forced to choose between
the main card or the 3D accelerators.  With 3D accelerators, I'm
going with a pure OpenGL solution.  But I will miss the blitting power
available with a 256 Megabyte AGP aperture!

Just a note about Direct Draw rotation:

Quote:>                   ....   If your not doing any 3D then the question might
> should be do you need GL at all.  DDraw will do the color keys and rotated
> blitting and will use any hardware acceleration your 2d card has.  DDraw can
> scale and rotate bitmaps nicely.

Direct Draw does NOT emulate blit rotation and most hardware does NOT
support it. You just get an unrotated blit with DDERR_NOROTATIONHW error
returned. That's what generated this thread to begin with.  You are correct
about scaling and color keys of course!

What I don't understand is why, in order to make OpenGL a viable competitor
with DDraw/D3D IM, better pixel resolution support isn't included in an
ancillary library.  With the DX solution, I know exactly how much video
mem space I need for texture caching for a given hardware configuration,
and I can tweak things.  This seems to be impossible under OpenGL.  But
I've only read half the Open GL programming guide, so maybe I just haven't
figured this out yet.

Thanks again. See ya.