请教OpenGL几个概念问题

请问OpenGL中rendering到底是什么意思？

The implementation of this approach begins with rendering a simple clip geometry to the depth buffer, i.e., the depth structure is generated from the clip geometry by standard scan conversion of the graphics hardware.

此句中rendering怎么理解？

standard scan conversion of the graphics hardware是什么？

OpenGL中有哪些函数是实现这些功能的？

谢谢！