Creating the Primary Surface
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4/8/2010
The primary surface is the surface currently visible on the monitor and is identified by the DDSCAPS_PRIMARYSURFACE flag. You can only have one primary surface for each DirectDraw object.
When you create a primary surface, remember that the dimensions and pixel format implicitly match the current display mode. Therefore, this is the one time you do not need to declare a surface's dimensions or pixel format. If you do specify them, the call will fail and return DDERR_INVALIDPARAMS — even if the information you used matches the current display mode.
Code Example
The following code example demonstrates how to prepare the DDSURFACEDESC structure members relevant for creating the primary surface.
Note
To make the following code example easier to read, security checking and error handling are not included. This code example should not be used in a release configuration unless it has been modified to include them.
DDSURFACEDESC ddsd;
ddsd.dwSize = sizeof(ddsd);
// Tell DirectDraw which members are valid.
ddsd.dwFlags = DDSD_CAPS;
// Request a primary surface.
ddsd.ddsCaps.dwCaps = DDSCAPS_PRIMARYSURFACE;
After creating the primary surface, you can retrieve information about its dimensions and pixel format by calling its IDirectDrawSurface::GetSurfaceDesc method.