void  SetupPointLight(int index,vect3d v,DWORD backgroundcolor,DWORD lightcolor,float dia)

                The light will create a new light or rewrite the existing light on this index. The range of point light is sphere.

                Important: You need set the camera position before you set the point light.

                index: All lights are assigned to a index.

                v: light position in world space

                background: the basic color of all surface in light sphere

                lightcolor: the diffuse color of this light by faces’s normals