How do you clip a concave polygon using Sutherland Hodgman polygon algorithm?
It is performed by processing the boundary of polygon against each window corner or edge. First of all entire polygon is clipped against one edge, then resulting polygon is considered, then the polygon is considered against the second edge, so on for all four edges.
Which polygons are correctly clipped by the Sutherland Hodgman algorithm?
Once all vertices have been processed for one clip window boundary, the output list of vertices is clipped against the next window boundary. Convex polygons are correctly clipped by the Sutherland-Hodgeman algorithm, but concave polygons may be displayed with extraneous lines, as demonstrated in Fig.
How many polygons are used in Sutherland Hodgman clipping method?
How many polygons are used in this method? Explanation: Two polygons are used in this algorithm namely clip polygon and subject polygon.
Which algorithm is better for polygon clipping?
Sutherland–Hodgman Algorithm
A convex polygon and a convex clipping area are given. The task is to clip polygon edges using the Sutherland–Hodgman Algorithm.
What is the use of polygon clipping?
polygon clipping Removal of part of an object outside a polygon (see clipping). Efficient algorithms exist that pipeline the sequence of edges that define the polygon to the set of planes to be clipped against. Polygon clipping is particularly difficult because it is necessary that closed polygons remain closed.
What are the types of polygon clipping?
Four Cases of polygon clipping against one edge
- Case 1 : Wholly inside visible region – save endpoint.
- Case 2 : Exit visible region – save the intersection.
- Case 3 : Wholly outside visible region – save nothing.
- Case 4 : Enter visible region – save intersection and endpoint.
What are the disadvantages of Sutherland hodgeman algorithm?
Disadvantages of sutherland hodgman polygon clipping algorithm
- It clips to each window boundary one at a time.
- It has a “Random” edge choice.
- It has Redundant edge-line cross calculations.
Can you use line clipping algorithm for polygon clipping?
Line clipping against a polygon is widely used in computer graphics such as the hidden line problem. A new line-clipping algorithm against a general polygon is presented in this paper. Each edge of the polygon is processed against a horizontal line, which makes the clipping process simpler.
Why is clipping important?
Clipping, in the context of computer graphics, is a method to selectively enable or disable rendering operations within a defined region of interest. A well-chosen clip allows the renderer to save time and energy by skipping calculations related to pixels that the user cannot see.
How many types of clipping are there?
There are four types of possible clipping processes, depending on which part of the word undergoes structural changes: back-clipping (temperature — temp, rhino — rhinoceros, gym — gymnasium), fore-clipping (helicopter — copter, telephone — phone, plane, aeroplane), mixed clipping (influenza — flu, refrigerator — fridge …
Which is the clip polygon in Sutherland Hodgman?
The Sutherland-Hodgman clipping algorithm finds the polygon that is the intersection between an arbitrary polygon (the “subject polygon”) and a convex polygon (the “clip polygon”).
Is there an algorithm for clipping polygons?
14. 14 Weiler-Atherton Polygon Clipping This algorithm was developed clip a fill area that is either a convex polygon or a concave polygon. The basic idea of this algorithm is that instead of proceeding around the polygon edges as vertices are processed, we will follow the window boundaries.
How is the edge of a polygon clipped?
The edge (of clipping area) is extended infinitely to create a boundary and all the vertices are clipped using this boundary. The new list of vertices generated is passed to the next edge of the clip polygon in clockwise fashion until all the edges have been used.
When do you clip polygons inside the window?
If the first vertex is outside the window boundary and the second vertex is inside Then , both the intersection point of the polygon edge with the window boundary and the second vertex are added to the output vertex list. 8. 8 Sutherland-Hodgman Polygon Clipping 2. If both input vertices are inside the window boundary.