What are the advantages and disadvantages of using the Sutherland-Hodgman algorithm for polygon clipping?

The Sutherland-Hodgman algorithm is a straightforward and efficient method for clipping convex polygons against a convex window, making it easy to implement for basic tasks. It's great for working with simple, convex shapes and directly provides the clipped result. However, it can struggle with concave polygons, as it may create multiple separate pieces or complex results that need extra handling. The algorithm is also limited to clipping against convex shapes, and it can face precision issues in certain cases. While it’s a good fit for simple applications, it’s not always the best choice for real-time rendering or complex polygon clipping.

The Sutherland-Hodgman algorithm can encounter difficulties with degenerate cases, such as vertices lying exactly on the clipping boundary. In a mapping application I worked on, this issue manifested in occasional anomalies in the clipped output, necessitating the implementation of additional logic to handle such edge cases explicitly, thereby complicating the overall algorithm. While the Sutherland-Hodgman algorithm is primarily suited for polygon clipping, adapting it for line clipping, particularly with the Cyrus-Beck extension, can introduce complexity. In an application designed for architectural design visualisation, extending the algorithm to support line clipping for wireframe models required intricate adjustments.

Cyrus-Beck Algorithm is a more general line-clipping algorithm that can handle both convex & concave clipping windows by utilizing the parametric form of lines & normals to the clipping window edges. Its ability to deal with concave clipping windows makes it versatile, providing a general solution for line clipping. The computational complexity can be higher compared to some other algorithms, especially for clipping regions with many edges, due to the need to compute dot products for each edge of the clipping window. Sklansky’s Convex Polygon Clipping Algorithm specifically addresses the clipping of a subject polygon against a convex clipping polygon using a stack-based approach to track intersection points & in-out statuses.

The Sutherland-Hodgman algorithm includes unnecessary lines when clipping concave polygons. And while the Weiler Atherton algorithm can handle this, it is more complicated to implement and has a higher time complexity. This is to say that both of these algorithms used for polygon clipping in computer graphics have settings where they are best utilized.