Init code

        HRESULT hr = S_OK;

        assert(m_pDev && m_pSurface && m_pVB && m_pRenderToSurface && m_pEffect && m_pHeightfield);

        V_RETURN(m_pDev->GetTransform(D3DTS_WORLD, &m_matWorldOrig));
        V_RETURN(m_pDev->GetTransform(D3DTS_VIEW, &m_matViewOrig));
        V_RETURN(m_pDev->GetTransform(D3DTS_PROJECTION, &m_matProjectionOrig));
        V_RETURN(m_pDev->SetTransform(D3DTS_WORLD, &m_matWorld));
        V_RETURN(m_pDev->SetTransform(D3DTS_VIEW, &m_matView));
        V_RETURN(m_pDev->SetTransform(D3DTS_PROJECTION, &m_matProjection));

        V_RETURN(m_pRenderToSurface->BeginScene(m_pSurface, &m_viewport ));
        V_RETURN(m_pDev->Clear( 0, NULL, D3DCLEAR_TARGET, 0x00ff0000, 1.0f, 0));
        V_RETURN(m_pDev->SetFVF(D3DFVF_XYZ));
        V_RETURN(m_pDev->SetStreamSource(0, m_pVB, 0, sizeof(vec3_ty)));
        V_RETURN(m_pEffect->SetTexture("g_Heightfield", m_pHeightfield));

        UINT passes = 0;
        V_RETURN(m_pEffect->Begin(&passes, 0));
        for (UINT i = 0; i < passes; ++i)
        {
            m_pEffect->BeginPass(i);
            V_RETURN(m_pDev->DrawPrimitive(D3DPT_POINTLIST, 0, 1));
        }
        m_pEffect->EndPass();
        V_RETURN(m_pEffect->End());

        V_RETURN(m_pRenderToSurface->EndScene( 0 ));
        V_RETURN(m_pDev->SetTransform(D3DTS_WORLD, &m_matWorldOrig));
        V_RETURN(m_pDev->SetTransform(D3DTS_VIEW, &m_matViewOrig));
        V_RETURN(m_pDev->SetTransform(D3DTS_PROJECTION, &m_matProjectionOrig));

        return hr;