Painter's algorithm: Difference between revisions

Revision as of 12:11, 9 November 2006

Revision as of 00:47, 10 January 2007

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[[Image:Painters_problem.png|right|frame|Overlapping polygons can cause the algorithm to fail]]

The algorithm can fail in certain cases. In this example, Polygons A, B and C overlap each other. It's not possible to decide which polygon is above the others or when two polygons intersect one another in three dimensions. In this case the offending polygons must be cut in some way to allow sorting to occur. [[Newell's_algorithm|Newell's algorithm]] proposed in 1972 gives a method for cutting such polygons. Numerous methods have also been proposed in the field of [[Computational_geometry | computational geometry]] .

In basic implementations, the painter's algorithm can be inefficient. It forces the system to [[rendering (computer graphics)|render]] each point on every polygon in the visible set, even if that polygon is occluded in the finished scene. This means that, for detailed scenes, the painter's algorithm can overly tax the computer hardware.