Retrieves the currently set pixel shader.
HRESULT GetPixelShader( IDirect3DPixelShader9** ppShader );
If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be D3DERR_INVALIDCALL.
This method will not work on a device that is created using D3DCREATE_PUREDEVICE.
Header: Declared in D3d9.h.