OpenGL vs Direct3D; dgl

I was poring through SDL_dx5video.c and saw a
comment to the effect than setting an OpenGL mode
will use the GDI instead of DirectX.

What I want to know is even if OpenGL uses a
hardware accelerated driver will it always be
at a disadvantage speedwise vis-a-vis Direct3D
because it cannot use DirectDraw?

And by the way what happened to Scitech’s dgl?

What I want to know is even if OpenGL uses a
hardware accelerated driver will it always be
at a disadvantage speedwise vis-a-vis Direct3D
because it cannot use DirectDraw?

many (all?) cards will fail initializing openGL when you call
IDirectDraw::SetDisplayMode()
that’s why SDL only use GDI when using OpenGL

in 3D only, there is no speed disadvantage with OpenGL
( the features are not the same, but no OpenGL/D3D war here :slight_smile: )

locking and accessing the frame buffer comes with a big penalty anyway, even
with D3D

Gautier - www.tlk.fr