Warnock algorithm
Warnock's algorithm is a hidden surface removal algorithm invented by John Warnock that is typically used in the field of computer graphics. This is a divide and conquer algorithm with run-time of O(n * p) where n is the number of polygons and p is the number of pixels in the viewport.
The inputs are a list of polygons and a viewport. The base case is that if the list of polygons is simple then draw the polygons in the viewport. Simple is defined as one polygon or a viewport that is one pixel in size. The continuous step is to split the viewport in 4 equally sized quadrants and to recursively call the algorithm 4 times where each polygon list is modified such that it only contains polygons that are visible in the new viewport.