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Robulus

creating multiple offscreen surfaces

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I'd like to create multiple offscreen surfaces so that I could update 1 surface while the other is being pageflipped... and then pageflip the first while I update the second. I tried creating 2 IDirect3DSurfaces, but I got unpredictable results as I have a primary process updating frames (for stereo 3D video) while the DirectX process pageflips. Is this possible? It's not a classic Chain Swap but more of an either/or swap. If Surface2 is ready for display, then present it until Surface1 is ready for display, at which time present Surface1 until Surface2 is ready for display...



STEREO3D_Direct3DDevice9->CreateOffscreenPlainSurface(STEREO3D_Width*2, STEREO3D_Height+1, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &STEREO3D_ImageSourceSurface1, NULL);

STEREO3D_Direct3DDevice9->CreateOffscreenPlainSurface(STEREO3D_Width*2, STEREO3D_Height+1, D3DFMT_A8R8G8B8, D3DPOOL_DEFAULT, &STEREO3D_ImageSourceSurface2, NULL);

D3DLOCKED_RECT LockedRect1, LockedRect2;

STEREO3D_ImageSourceSurface1->LockRect(&LockedRect1, NULL, 0);
STEREO3D_ImageSourceSurface2->LockRect(&LockedRect2, NULL, 0);

LPNVSTEREOIMAGEHEADER pStereoImageHeader1 = (LPNVSTEREOIMAGEHEADER)(((unsigned char *) LockedRect1.pBits) + (LockedRect1.Pitch * (STEREO3D_Height)));

LPNVSTEREOIMAGEHEADER pStereoImageHeader2 = (LPNVSTEREOIMAGEHEADER)(((unsigned char *) LockedRect2.pBits) + (LockedRect2.Pitch * (STEREO3D_Height)));

pStereoImageHeader1->dwSignature = NVSTEREO_IMAGE_SIGNATURE;
pStereoImageHeader2->dwSignature = NVSTEREO_IMAGE_SIGNATURE;
pStereoImageHeader1->dwBPP = 32;
pStereoImageHeader2->dwBPP = 32;
pStereoImageHeader1->dwWidth = STEREO3D_Width*2;
pStereoImageHeader2->dwWidth = STEREO3D_Width*2;
pStereoImageHeader1->dwHeight = STEREO3D_Height;
pStereoImageHeader2->dwHeight = STEREO3D_Height;

STEREO3D_ImageSourceSurface1->UnlockRect();
STEREO3D_ImageSourceSurface2->UnlockRect();

RECT destRect;
destRect.left = 0;
destRect.top = 0;
destRect.right = STEREO3D_Width;
destRect.bottom = STEREO3D_Height;

MSG ThisMessage;

do
{
while (PeekMessage(&ThisMessage, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&ThisMessage);
DispatchMessage (&ThisMessage);
}

STEREO3D_Direct3DDevice9->BeginScene();
STEREO3D_Direct3DDevice9->GetBackBuffer(0, 0, D3DBACKBUFFER_TYPE_MONO, &STEREO3D_BackBufferSurface);

if (STEREO3D_PresentPair1)
{
STEREO3D_Direct3DDevice9->StretchRect(STEREO3D_ImageSourceSurface1, NULL, STEREO3D_BackBufferSurface, &destRect, D3DTEXF_NONE);
}
else
{
STEREO3D_Direct3DDevice9->StretchRect(STEREO3D_ImageSourceSurface2, NULL, STEREO3D_BackBufferSurface, &destRect, D3DTEXF_NONE);
}

STEREO3D_Direct3DDevice9->EndScene();

STEREO3D_Direct3DDevice9->Present(NULL, NULL, NULL, NULL);
}
while (ThisMessage.wParam != VK_ESCAPE);

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From your source code, why don't you use Swapchain?

A swap chain is a series of virtual framebuffers utilized by the graphics card and graphics API for frame rate stabilization and several other functions. The swap chain usually exists in graphics memory, but it can exist in system memory as well. The non-utilization of a swap chain will result in stuttering rendering, but its existence and utilization are required by many graphics APIs. A swap chain with two buffers is a double buffer, and one with three is a triple buffer.

In every swap chain there are at least two buffers. One is front buffer or screen buffer which contains the contents you see on the screen. 1 or more called back buffer which can be used to render new frame(s) while a frame is presented/displayed to the screen.

http://en.wikipedia.org/wiki/Swap_Chain
http://en.wikipedia.org/wiki/Back_buffer#Double_buffering

If you insist to create some surfaces then present them to the screen you need to create a Render target.

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