d3d在win消息循环是也能显示

LRESULT CALLBACK d3d::WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam){switch( msg ){//防止拖曳和拉伸时不进行绘制case WM_PAINT:Display();break;case WM_DESTROY:::PostQuitMessage(0);break;case WM_KEYDOWN:if( wParam == VK_ESCAPE )::DestroyWindow(hwnd);break;}return ::DefWindowProc(hwnd, msg, wParam, lParam);}