https://learn.microsoft.com/en-us/windows/win32/api/d3d9/nf-d3d9-idirect3ddevice9-getclipplane
IDirect3DDevice9::GetClipPlane (d3d9.h) - Win32 apps | Microsoft Learn
The IDirect3DDevice9::GetClipPlane method (d3d9.h) retrieves the coefficients of a user-defined clipping plane for the device.
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