An anonymous reader writes: Developer Pekka Väänänen has posted a fascinating report on how he got Quake running on an oscilloscope (video link). Obviously, the graphic details gets stripped down to basic lines, but even then, you need to cull any useless or unseen geometry to make things run smoothly. He says, "To cull the duplicates a std::unordered_set of the C++ standard library is used. The indices of the triangle edges are saved in pairs, packed in a single uint64_t, the lower index being first. The set is cleared between each object, so the same line could still be drawn twice or more if the same vertices are stored in different meshes. Before saving a line for end-of-the-frame-submit, its indices in the mesh are checked against the set, and discarded if already saved this frame. At the end of each frame all saved lines are checked against the depth buffer of the rendered scene. If a line lies completely behind the depth buffer, it can be safely discarded because it shouldn't be visible."