Cases of the sutherland hodgman polygon clipping algorithm, Computer Graphics

Cases of the Sutherland Hodgman Polygon Clipping Algorithm

In order to clip polygon edges against a window edge we move from vertex Vi to the subsequent vertexVi+1 and choose the output vertex as per to four simple tests or rules or cases listed here in below:

Table: Cases of the Sutherland-Hodgman Polygon Clipping Algorithm

Case

Vi

Vi+1

Output Vertex

A

Inside window)

Inside

Vi+1

B

Inside

Outside

V'i   i.e  intersection of polygon and window edge

C

Outside

Outside

None

D

Outside

Inside

V'I  ; Vi+1

Conversely, the 4 possible Tests listed above to clip any polygon conditions are as mentioned here:

1) If both Input vertices are within the window boundary then only second vertex is added to output vertex list.

2) If first vertex is within the window boundary and the 2nd vertex is outside then, merely the intersection edge along with boundary is added to output vertex.

3) If both Input vertices are outside the window boundary then nothing is added to the output list.

4) If the first vertex is outside the window and the 2nd vertex is within window, then both the intersection points of the polygon edge along with window boundary and second vertex are added to output vertex list.

Here, we can utilize the rules cited above to clip a polygon properly. The polygon should be tested against each edge of the clip rectangle; new edges should be added and existing edges must be discarded, retained or divided. In fact this algorithm decomposes the problem of polygon clipping against a clip window in the same sub-problem where a sub-problem is to clip all polygon edges that is pair of vertices in succession against a particular infinite clip edge. The output is a set of clipped edges or pair of vertices which fall in the visible side along w.r.t. clip edge. Such set of clipped edges or output vertices are taken as input for the subsequent sub-problem of clip against the second window edge. Hence, identifying the output of the earlier sub-problem as the input, all of the sub-problems are solved in sequence, at last yielding the vertices which fall on or inside the window boundary. These vertices linked in order forms, the shape of the clipped polygon.

Posted Date: 4/3/2013 3:48:19 AM | Location : United States







Related Discussions:- Cases of the sutherland hodgman polygon clipping algorithm, Assignment Help, Ask Question on Cases of the sutherland hodgman polygon clipping algorithm, Get Answer, Expert's Help, Cases of the sutherland hodgman polygon clipping algorithm Discussions

Write discussion on Cases of the sutherland hodgman polygon clipping algorithm
Your posts are moderated
Related Questions
Remark for the Bresenham Line Generation Algorithm Remark: The algorithm will be properly the same if we suppose | m | Algorithm | m | (a) Input two line endi

What do you mean by scan conversion?  A main task of the display processor is digitizing a picture definition given in an application program into a set of pixel-intensity valu

Basic Approaches for Visible Surface Determination There are two basic approaches for visible-surface determination, as per if they deal along with their projected images or a

Parameterized Systems - Computer Animation Parameterized Systems is the systems which permit objects motion features to be given as part of the object descriptions. The adjus

Sound and Audio: Sound is a mechanical energy disturbance which propagates by matter as a wave. Sound is characterized through the various properties that are: frequency, per

2D Line Segment Generation  A digitally plotted line is basically an approximation of infinite number of points on an abstract line segment by only a finite number of points on

QUESTION (a) Describe the following Mean Filters used as Noise Reduction filters: 1. Arithmetic Mean Filter. 2. Geometric Mean Filer. 3. Harmonic Mean Filter. You a

Essentialily of Computer Simulation You may want to understand why to do simulation? Is there any one way to perform the tasks? To converse these matters lets briefly discuss

Digital & Interactive Media has been developed in 20th century: New media improve visual and verbal content. It doesn¹t replace earlier media. New media lets dynamic alteration of

explain about gks