视口方面的程序问题！

dafengq

小弟在右下角开了一个小视口，不知为什么运行程序时不见了，肯定是程序写的有问题，请各位高手指教！不胜感谢！
Device->Clear(0, 0, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0xffffffff, 1.0f, 0);
Device->BeginScene();
…………
draw other objects
…………
//another viewport
        D3DVIEWPORT9 vpp;//initialize the viewport
        D3DVIEWPORT9 viewData = { 576, 432, 64, 48, 0.0f, 1.0f };
                Device->GetViewport(&vpp);
                Device->SetViewport(&viewData);

                      //draw 2 triangles
                Device->SetStreamSource(0, Triangle, 0, sizeof(Vertex));
                Device->SetFVF(Vertex::FVF);
        Device->SetTransform(D3DTS_WORLD, &ObjWorldMatrices[1]);
        Device->SetTexture(0, Tex[1]);
                Device->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 2);
                Device->SetViewport(&vpp);

                Device->EndScene();
                Device-&gtresent(0, 0, 0, 0);