I guess we haven't talked about this slide in the lecture, but what exactly does this slide mean? Anyone know what is near/far plane clipping and what the figure is about?

Basically, anything too close or too far from the camera will not be displayed on screen due to limit of precision. Z-fighting is caused by insufficient precision in the depth buffer. Link: https://en.wikipedia.org/wiki/Z-fighting

One technique to address the z-fighting issue is to set the near plane sufficiently far in the scene (but not too far) to the point where high degree of floating point precision is needed. But generally, positioning the triangles in the scene where they don't overlap, or using a higher precision depth buffer, is a decent strategy.

depth testing.