Re: [AD] Fw: Acquire/Release speed issue

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Angelo, what is the situation under MacOS X? I see the driver implements the create_video_bitmap method, so you're likely on the Windows side. But it doesn't seem to reuse the screen for the first video bitmap with the same
dimensions?  If so, how does it support page flipping?

When I implemented the OSX video bitmaps support the whole Carbon Quickdraw hw acceleration issue was still somewhat unknown for me. I modeled after the QNX port, but eventually there was some problem with reusing the screen IIRC... In any way, I left the thing untouched just to make the OSX port to support at least page flipping. Which is not exactly page flipping, but actually is double buffering. I know this is plain wrong, but a lot of programs expect page flipping to work in some way (even a lot of the Allegro examples), but given the fact I now have a more complete view of the OSX environment, I can say the OS doesn't support any 2d hw acceleration directly. You *always* just work on buffers, then the window server composites the windows using OpenGL. Or you can use OpenGL directly. But if you don't, there is no way to obtain hw acceleration nor any hardware feature, as you're really working on a buffer in system memory. The Quickdraw API I used was created with older MacOS versions in mind, where acceleration was possible. But under OSX it doesn't work as it was meant to, I've discovered this later. The current OSX show_video_bitmap() hook simply copies another video bitmap (created using NewGWorld, which in Quickdraw should create a surface using VRAM or AGP accessible memory, but as I discovered later it just creates it out of normal RAM) onto the screen using CopyBits (which in Quickdraw should be accelerated). As I explained though, this is just an hack to emulate page flipping, and without acceleration anyway.

What should I do? Should I remove the whole video bitmaps support from OSX, as it's not really following the docs?

--
Angelo Mottola
a.mottola@xxxxxxxxxx





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