在三维场景中绘制两个球体，一个纹理贴图，一个启用颜色混合实现透明效果。使用鼠标可以托动任意球体，当球体叠加时，托动的是离屏幕最近的球体-Draw three-dimensional scene in two spheres, a texture, color mixing to achieve a transparent effect is enabled. Use the mouse to drag the arbitrary sphere, when the ball stack, the