surface copy 的幾個方法

1.IDirect3DDevice9::StretchRect texture to RT texture RT texture to RT texture 2.IDirect3DDevice9::GetRenderTargetData POOL_DEFAULT to D3DPOOL_SYSTEMMEM (RT texture to texture) 3.IDirect3DDevice9::UpdateTexture D3DPOOL_SYSTEMMEM to D3DPOOL_DEFAULT (texture to RT texure)