So far I have successfully loaded bitmaps to DirectDraw surfaces and flip them to create animation. Right now I am trying to mirror an image and the most peculiar thing happens. Snippets of my code as follows. The mirror (and color key) works only if the destination rectangle has a different height/width than the source rectangle. Otherwise, I can Blt to the destination, but no mirror and no transparency.

...

destRect.top = y;
destRect.left = x;
destRect.bottom = y + width;
destRect.right = x + height;

ZeroMemory( &ddfx, sizeof( ddfx ) );
ddfx.dwSize = sizeof( ddfx );
ddfx.dwDDFX = DDBLTFX_MIRRORLEFTRIGHT;

result = pCanvas->Blt( &destRect, pSurface, &srcRect, DDBLT_KEYSRC | DDBLT_DDFX, &ddfx );

...

The code as above will blt the image from pSurface to pCanvas. However it will not mirror or use transparency when blitting. Yet if I add one to destRect.bottom or destRect.right, it works. Of course the image is thus a little distorted due to stretching. Just hoping that someone else has also come across this and know what is going on...? [edited by - flamewill on August 15, 2003 8:32:02 PM]

Thanks for your help, KalvinB. I tried to reply to my previous (identical) post, but the "Reply To Topic" doesn''t work! I really need to get that gremlin off my back.

Back on topic. It must have something to do with the RECT''s because blitting that image results in the error: DDERR_INVALIDRECT. Unfortunately, even after I adjusted the source and destination rectangles the problem wasn''t fixed.

The more peculiar thing is that the DDERR_INVALIDRECT error only pops up during the first three scans. The image is still there... What am I missing?

Just found out what the DDERR_INVALIDRECT problem is: a dumb bug in my code (as it usually is). The initial problem is still there, no mirror, no transparency, and no DDERR...

Oh, no. Please don''t misunderstand, I''m not blaming Microsoft for this - although I love blaming Microsoft on many other things. I''m trying to find out if others have also experienced this or a similar problem.

I agree that 99% of the time the programmer has overlooked something. That''s why I spend 99% of the time debugging my code, and 1% of the time asking for help in the forums.