DirectDraw still the fastest for direct framebuffer access?

Doesn't make too much of a difference what you use, as you will be limited by the PCIe bus to the graphics card. It's usually the fastest to write to system memory, and then have the driver send the image to the GPU. If you want to write directly, D3D9 is probably the easiest way, as you can create a device with a lockable back-buffer.

This is one of those "Technically True" answers but technically, if you want the fastest access to the framebuffer, a pixel shader is where it's at.

That or CUDA and other such things.

I'm not tryin to be a smart aleck with this, they could potentially be good avenues to pursue depending on what you are trying to do.

Some people have done raytracers in pixel shaders for instance.

If your code runs on the video card, it has the fastest access to the video memory.

Thanks, and thanks.

If the PCIe bus is the bottleneck, then I guess it's true it wouldn't matter much whether I use glDrawPixels or DirectDraw or DirectX Graphics.

Pixel shaders are an interesting suggestion. I'm testing out some software renderer ideas.

I honestly don't know what's fastest if you want to do CPU rendering. I know a lot of people use pixeltoaster for such purposes.

I don't think there has been hardware support for DirectDraw in some time now. Can anyone correct me if I'm mistaken?

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Original post by Flimflam I don't think there has been hardware support for DirectDraw in some time now. Can anyone correct me if I'm mistaken?

No, I think you're right. I'd also guess though that DD can potentially take some shortcuts that more general-purpose stuff like GDI can't. I did an interesting test last year between DirectDraw, GDI, GDI+ and Direct3D for writing the end result of a software renderer to screen, and on XP DirectDraw was the fastest by quite a margin. This was non-exclusive DirectDraw using 32-bit surfaces too. I haven't yet repeated it on Windows 7 (I never got to run it on Vista), and haven't even looked at Direct2D.