调用clear清除背景后，即可通过init中创建的顶点数据和三角形绘制对象。

After a call to clear erases the background, you draw the cube by using the vertex data and triangles created in init .

youdao

调用clear清除背景后，即可通过init中创建的顶点数据和三角形绘制对象。

After a call to clear erases the background, you draw the cube by using the vertex data and triangles created in init .

youdao