Adds a dirty region to a texture resource.
HRESULT AddDirtyRect( CONST RECT * pDirtyRect );
If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be D3DERR_INVALIDCALL.
For performance reasons, dirty regions are only recorded for level zero of a texture. For sublevels, it is assumed that the corresponding (scaled) rectangle or box is also dirty. Dirty regions are automatically recorded when LockRect or IDirect3DVolumeTexture9::LockBox is called without D3DLOCK_NO_DIRTY_UPDATE or D3DLOCK_READONLY. Also, the destination surface of IDirect3DDevice9::UpdateSurface is marked dirty.
Applications can optimize what subset of a resource is copied by specifying dirty regions on the resource.
Header: Declared in D3d9.h.