Exterior Clipping

Exterior clipping is a process in computer graphics that involves removing parts of an object or image that are outside of a specified boundary or viewing region. This technique is often used to optimize rendering performance by reducing the amount of processing required for objects that are not visible on the screen.

There are several algorithms and techniques for exterior clipping, including:

1. Cohen-Sutherland algorithm: This algorithm is used for line clipping and involves dividing the viewing region into multiple areas, with each area assigned a specific code based on its location relative to the object being clipped. Lines that fall completely outside the viewing region can be quickly discarded, while lines that intersect the viewing region can be clipped to fit within the boundaries.

2. Sutherland-Hodgman algorithm: This algorithm is used for polygon clipping and involves dividing the polygon into multiple edges and clipping each edge against the viewing region. The resulting clipped edges can then be assembled to form a new clipped polygon.

3. Z-buffer algorithm: This algorithm involves storing the depth or distance of each pixel in the scene relative to the viewer, allowing objects that are closer to the viewer to be displayed in front of objects that are farther away. This can be used to quickly discard objects that are not visible in the viewing region.

Exterior clipping can significantly improve rendering performance by reducing the amount of processing required for objects that are not visible on the screen. By using algorithms and techniques such as the Cohen-Sutherland or Sutherland-Hodgman algorithm, designers and developers can optimize their graphics applications to improve performance and provide a smoother user experience.