Input is in the form of vertices of the polygon in clockwise order. Polygon clipping is one of those humble tasks computers do all the time. The sutherland hodgman algorithm is used for clipping polygons. Sutherlandhodgeman polygon clipping ecomputernotes. It spendsologp time on each edge of the clipped polygon, wherep is the number of window edges, while the sutherlandhodgman algorithm spendsop time per edge. The oldest one from 1974 is called the sutherlandhodgman algorithm. Weileratherton polygon clipping convex polygons are correctly clipped by the sutherlandhodgman algorithm, but concave polygons may be displayed with extra areas area inside the red circle, as demonstrated in the following figure. This code clip a polygon with sutherlandhodgman algorithm. Pdf polygon clipping is an important operation that computers. Single edge sn of nonconvex polygon per iteration is analyzed. A polygon can be clipped by processing its boundary as a whole against each window edge. There are several wellknown polygon clipping algorithms, each having its strengths and weaknesses. This image from wikimedia commons demonstrates this quite well. The sutherland hodgman algorithm clips a polygon against all edges of the clipping region in turn.
Multiplepolygons may result from clipping a singlepolygon. Php polygon clipping using the sutherlandhodgman algorithm. I wrote a php implementation of the polygon clipping algorithm by sutherlandhodgman. The task is to clip polygon edges using the sutherland hodgman algorithm. It spendsologp time on each edge of the clipped polygon, wherep is the number of window edges, while the sutherland hodgman algorithm spendsop time per edge. The sutherlandhodgmanalgorithm is a wellknown algorithm for clipping a polygon against a rectangle. More than 50 million people use github to discover, fork, and contribute to over 100 million projects.
Cohen sutherland and cyrusbeck line clipping algorithms. May 30, 2014 a simple video that explains the working of sutherland hodgman polygon clipping algorithm in detail. An implementation of the sutherlandhodgman algorithm used for clipping polygons in c. Mar 20, 2015 polygon clipping algorithm by sutherland and hodge.
Visualizing the sutherland hodgman algorithm harold serrano. There are 4 rules explained in sutherlandhodgman algorithm for clipping polygons. An efficient algorithm for line and polygon clipping springerlink. This is a part of mumbai university mca colleges computer graphics cg mca sem 2. Sutherlandhodgeman polygon clipping programs and notes. Sutherland hodgman polygon clipper by hamed sheidaian from. Polygon clipping and filling computer science department. Poligon clipping sutherland hodgeman algorithm in hindi. A single polygon can actually be split into multiple polygons can you draw an example. Clip single polygon using single infinite clip edge repeat 4 times note the generality. In this algorithm, all the vertices of the polygon are clipped against each edge of the clipping window. Understanding sutherlandhodgman clipping for physics engines. Sutherlandhodgman polygon clipping thesutherlandhodgmanalgorithmcorrectlyclips convex polygons,butconcave polygonsmaybe.
It spendsologp time on each edge of the clipped polygon, wherep is the number of window edges, while the sutherlandhodgman algorithm spendsop time. The algorithm steps from vertex to vertex, adding 0. Program to illustrate the implementation of 3d rotation transformation along. Polygon clipping sutherland hodgman algorithm a polygon can also be clipped by specifying the clipping window. Weileratherton clipping algorithm n sutherland hodgman required at least 1 convex polygon n weileratherton can deal with 2 concave polygons n searches perimeter of subj polygon searching for borders that enclose a clipped filled region n finds multiple separate unconnected regions a d c b a c d b subj clip 6 5 4 3 2 b 1. In vertexarray is the array of input polygon vertices. The algorithm proceeds in stages by passing each clipped polygon to the next edge of the windows and clipping. The algorithm demonstrates the practicality of various ideas from computational geometry. Polygon clipping sutherlandhodgman algorithm geeksforgeeks. Computer graphics sutherlandhodgeman polygon clipping. Application of sutherland hodgman polygon clipping.
Polygon clipping ppt polygon convex set free 30day. Explain the modification given by weiler and atherton for concave polygon. May 19, 2011 sutherland hodgeman polygon clipping the algorithm begins with an input list of all vertices in the subject polygon. Oct 16, 2012 clipping algorithm in computer graphics 1. Polygon clipping algorithm by sutherland and hodgeman c program. Consider each edge e of clipping area and do following. The idea is to clip each line segment of the input polygon against one clipping plane at a time. Php polygon clipping using the sutherland hodgman algorithm clip. Sutherlandhodgeman polygon clipping this program is for implementing sutherlandhodgeman polygon clipping.
All files are downloaded from the publishers website, our file servers or download mirrors. This is achieved by processing all polygon vertices against each clip rectangle boundary in turn. To generate first and follow for given grammar c programsystem programming and compiler constructionheres a c program to generate first and follow for a give grammar program. 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. Windowing conceptsclipping introduction brute force cohen sutherland clipping algorithmarea clipping sutherland hodgman area clipping algorithm 2. Sutherland hodgman polygon clipper by hamed sheidaian. Thus, an intersection point is calculated and saved. Sutherlandhodgeman polygon clipping algorithm c program. There are 4 rules explained in sutherland hodgman algorithm for clipping polygons.
An efficient algorithm for line and polygon clipping. It works by extending each line of the convex clip polygon in turn and selecting only vertices from the subject polygon that are on the visible side. Due to the size or complexity of this submission, the author has submitted it as a. The task is to clip polygon edges using the sutherlandhodgman algorithm.
Clipping polygons the sutherland hodgman algorithm clipping polygons would seem to be quite complex. Written in php, a micro channel public number of articles. The laingbarsky algorithm 1983 is a good deal more complicated, but in certain cases fewer intersections need to be calculated than for sutherland hodgman. The weileratherton algorithm overcomes this by returning a set of divided polygons, but is more complex and computationally more expensive, so sutherlandhodgman is used for many rendering applications. It solves a series of simple and identical problems that, when combined, solve the overall problem. Poligon clipping sutherland hodgeman algorithm in hindi computer graphics. Program to show the implementation of cohen sutherland line clipping algorithm. Sutherlandhodgeman polygon clipping programs and notes for mca.
The algorithm you present is not the sutherlandhodgmanalgorithm for clipping against an arbitrary polygon, but the cohensutherlandalgorithm for clipping against a rectangular viewport. Clip polygon pto clipping edge foreachedge in polygon p check clipping cases there are 4 case 1. An algorithm that clips a polygon is rather complex. Polygon clipping sutherlandhodgmanpolygon clipping algorithm and weileratherton polygon clipping algorithm. Theoretical and experimental analyses show that the.
The sutherland hodgeman polygon clipping algorithm. Its a basic operation in creating graphic output of all kinds. Sutherland hodgeman polygon clipping algorithm codes and scripts downloads free. Single step of internal loop of sutherlandhodgman clipping algorithm, where certain edge of convex polygon denotes halfpace grayed area inside.
Clip a polygon by successively clipping against each infinite clip edge after each clipping a new set of vertices is produced. Apply it for calculating the saved portion of a line from 2, 7 to 8, 12 in a window x w min y w min 5 and x w max y w max 10. Sutherland hodgman polygon clipping algorithm author. Clipping algorithm in computer graphics linkedin slideshare. It is performed by processing the boundary of polygon against each window corner or edge. To associate your repository with the polygonclippingalgorithm topic, visit. We need an organized way to dealwith all these cases. Sutherlandhodgman polygon clipping you are encouraged to solve this task according to the task description, using any language you may know. Clipping polygons the sutherlandhodgman algorithm clipping polygons would seem to be quite complex. We can correctly clip a polygon by processing the polygon boundary as whole each window edge. Pdf polygon clipping and polygon reconstruction researchgate. Next, one side of the clip polygon is extended infinitely in both directions, and the path of the subject polygon is traversed. If the first vertex is inside and the second is outside compute the intersection with the border of the clipping area and save it. Sutherland hodgeman polygon clipping the algorithm begins with an input list of all vertices in the subject polygon.
What is sutherlandhodgman polygon clipping algorithm in. Application of sutherland hodgman polygon clipping, computer. Explain sutherland hodgeman algorithm for polygon clipping. The sutherlandhodgman algorithm is an algorithm used for clipping polygons. Video explains with help of an example the working of the algorithm. Sutherland hodgman clipping algorithm, by wojciech mula. We present an algorithm for clipping a polygon or a line against a convex polygonal window. Program of sutherland hodgemann algorithm for polygon clipping. Two parallel methods for polygon clipping request pdf. Opengl glut lib sutherland hodgman c polygon clip search and download opengl glut lib sutherland hodgman c polygon clip open source project source codes from.
A simple video that explains the working of sutherlandhodgman polygon clipping algorithm in detail. Program to show the implementation of sutherland hodgeman polygon clipping. That article explains the algorithm and it also explains the code. Php polygon clipper using the sutherlandhodgman algorithm.
Download applet with source 23kb view applet online. Polygon clipping algorithm by sutherland and hodgeman c. Sutherlandhogson polygon clipping javascript github. Clipping polygons n cohensutherland and liangbarsky clip line segments against each window in turn n polygons can be fragmented into several polygons during clipping n may need to add edges n need more sophisticated algorithms to handle polygons. The sutherlandhodgman algorithm clips a polygon against all edges of the clipping region in turn. Disadvantages of sutherland hodgman polygon clipping. Polygon clipping and polygon reconstruction citeseerx.
In the first case, p1 is in front of the plane and p2 is on the back. The sutherlandhodgman clipping algorithm finds the polygon that is the intersection between an arbitrary polygon the subject polygon and a convex polygon the clip polygon. The simple problem is to clip a polygon against a single infinite clip edge. Sutherland hodgman polygon clipping algorithm right clip boundary bottom clip boundary left clip boundary top clip boundary idea. To accomplish this task, it is not enough to clip the lines one by one with e.
Polygon clipping sutherland hodgmanpolygon clipping algorithm and weileratherton polygon clipping algorithm. Sutherlandhodgman polygonclipping algorithm right clip boundary bottom clip boundary left clip boundary top clip boundary idea. The code snippet seems to be taken directly from the corresponding wikipedia article. It is used in computer graphics especially 2d graphics to reduce the complexity of a scene being displayed by eliminating parts of a polygon that do not. Download sutherland hodgeman polygon clipping algorithm. Sutherlandhodgeman clipping sutherlandhodgeman polygon clipping 2 2 2. The sutherland hodgeman polygon clipping algorithm slideshare.
In polygon clipping, we use an algorithm that generates one or more closed areas that are then scan converted for the appropriate area fill. The algorithm takes an input polygon and some clipping planes, and outputs a new polygon. Feb 14, 2017 poligon clipping sutherland hodgeman algorithm in hindi computer graphics. Polygon clipping ppt free download as powerpoint presentation. Request pdf two parallel methods for polygon clipping a control parallel and a novel data parallel implementation of the sutherlandhodgman polygon clipping algorithm are presented. If both vertices are inside the clipping area save the second. Polygon clipping algorithm by sutherland and hodge. Vertices from the input list are inserted into an output list if they lie on the visible side of the. Therefore, it may be somewhat faster when many polygon lines intersect with the clipping boundaries. Sutherland hodgman polygon clipping algorithm pracspedia. The sutherlandhodgman polygonclipping algorithm divide and conquer idea.
Sutherland hodgeman polygon clipping this program is for implementing sutherland hodgeman polygon clipping. Sutherlandhodgman algorithm each edge of the polygon must be testedagainst each edge of the clip rectangle. Sutherland and hodgmans polygonclipping algorithm uses a divideandconquer strategy. Clip polygon pto clipping edge foreachedge in polygon p. Sutherland hodgeman polygon clipping algorithm is used for polygon clipping. The output of a polygon clipper should be a sequence of vertices that define the clipped polygon boundaries. A convex polygon and a convex clipping area are given. Program to implement sutherlandhodgeman polygon clipping. A scene is made up of a collection of objectsspecified in world coordinates world coordinates 3. The algorithm you present is not the sutherland hodgman algorithm for clipping against an arbitrary polygon, but the cohen sutherland algorithm for clipping against a rectangular viewport.
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