Juan 1.1

The document discusses different algorithms for visible surface determination in 3D computer graphics, including the painter's algorithm, quadtree algorithm, and z-buffer algorithm. It explains that the painter's algorithm sorts polygons from back to front but has problems. The quadtree algorithm subdivides the screen until regions contain zero or one edge. The key insight of the z-buffer algorithm is that each pixel only displays one triangle, ignoring objects behind it. A z-buffer stores the z-value of the closest triangle at each pixel location.