演示如何使用的定向光源D3DX对象。你可以轨道现场使用向左箭头和向右箭头键。此外你可以提高相机的上箭头$r键和$l下箭头$r键。-Demonstrates how to use the directional light source object d3dx. You can track the scene using the left arrow and right arrow keys. In addition, you can improve the camera UP and DOWN