Sutherlandhodgeman polygon clipping computer notes. Polygon clipping, sutherlandhodgman algorithm, simplification, polygon. This is a part of mumbai university mca colleges computer graphics cg mca sem 2. Application of sutherland hodgman polygon clipping, computer. The algorithm steps from vertex to vertex, adding 0. The algorithm demonstrates the practicality of various ideas from computational geometry.
Newman image processing editor reentrant polygon clipping ivan e. Polygon clipping is one of the complex operations in computational geometry. Poligon clipping sutherland hodgeman algorithm in hindi computer graphics. Computer graphics sutherlandhodgeman polygon clipping with computer graphics tutorial, line generation algorithm, 2d transformation, 3d computer. Disadvantages of sutherland hodgman polygon clipping. In this algorithm, all the vertices of the polygon are clipped against each edge of the clipping window. The algorithm you present is not the sutherlandhodgmanalgorithm for clipping against an arbitrary polygon, but the cohensutherlandalgorithm for clipping against a rectangular viewport. Poligon clipping sutherland hodgeman algorithm in hindi. A convex polygon and a convex clipping area are given.
Foley, van dam, feiner, and hughes, computer graphics principles and practice, section 3. Php polygon clipping using the sutherlandhodgman algorithm clip. Sutherland hodgeman polygon clipping this program is for implementing sutherland hodgeman polygon clipping. 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. Mathematically, clipping can be described using the terminology of constructive geometry. Clipping is performed by computing intersections with four. Oct 16, 2012 clipping algorithm in computer graphics 1. The algorithm steps from vertex to vertex, adding 0, 1, or 2. Polygon clipping algorithm by sutherland and hodgeman c. Pdf polygon clipping code in cpp find, read and cite all the research you need on researchgate.
Polygon clipping and filling computer science department. Unlike sutherland hodgman polygon clipping algorithm, this algorithm is able to clip concave polygons without leaving any residue behind. Polygon clipping sutherlandhodgman, weileratherton polygon filling scan filling polygons flood filling polygons pattern filling polygons. It is performed by processing the boundary of polygon against each window corner or edge.
Reentrant polygon clipping gettysburg college computer. It solves a series of simple and identical problems that, when combined, solve the overall problem. Input is in the form of vertices of the polygon in clockwise order. Computer graphics sutherland hodgeman polygon clipping algorithm c program. Sutherland hodgman polygon clipping algorithm right clip boundary bottom clip boundary left clip boundary top clip boundary idea. There are several wellknown polygon clipping algorithms, each having its strengths and weaknesses. First make a list of all intersection points namely i 1, i 2, i 3. The task is to clip polygon edges using the sutherland hodgman algorithm. Php polygon clipping using the sutherlandhodgman algorithm. Sutherlandhodgman polygon clipping pseudo code for. The oldest one from 1974 is called the sutherlandhodgman algorithm, as presented. Hodgman evans and sutherland computer corporation a new family of clipping algorithms is described.
Computer graphics assignment help, application of sutherland hodgman polygon clipping, for good understanding of the application of the rules specified above see the following figure, where the shaded region demonstrates the clipped polygon. In geometry a polygon is a flat shape consisting of straightlines that are joined to form a circuit. Use the sketches provide to show the intermediate clipping result of the sutherlandhodgman algorithm please follow strictly algorithm given in our lecture. Polygon clipping sutherlandhodgman algorithm geeksforgeeks. Sutherlandhodgman algorithm contd the algorithm clips every polygon edge against each clipping line use an output list to store newly clipped polygon vertices with each polygon edge, 1 or 2 vertices are added to the output list s p. Polygon clipping and polygon reconstruction citeseerx. Next, one side of the clip polygon is extended infinitely in both directions, and the path of the subject polygon is traversed. Clipping, in the context of computer graphics, is a method to selectively enable or disable rendering operations within a defined region of interest.
We present an algorithm for clipping a polygon or a line against a convex polygonal window. The algorithm proceeds in stages by passing each clipped polygon to the next edge of the windows and clipping. The oldest one from 1974 is called the sutherlandhodgman algorithm. 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. Computer graphics i polygon clipping and filling week 3, lecture 5. A single polygon can actually be split into multiple polygons can you draw an example. In other words, we can say that computer graphics is a rendering tool for the generation and manipulation of images. Mar 20, 2015 polygon clipping algorithm by sutherland and hodgeman c program. May 04, 2019 sutherland hodgman algorithm polygon clipping. Polygon clipping algorithm by sutherland and hodgeman c program. Sutherland hodgman polygon clipping algorithm author.
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. A scene is made up of a collection of objectsspecified in. The sutherlandhodgman algorithm is an algorithm used for clipping polygons. It involves computations, creation, and manipulation of data. An efficient algorithm for line and polygon clipping springerlink. Therefore, it may be somewhat faster when many polygon lines intersect with the clipping boundaries. Polygon clipping is one of those humble tasks computers do all the time. Polygon clipping sutherland hodgman algorithm a polygon can also be clipped by specifying the clipping window. A polygon can be clipped by processing its boundary as a whole against each window edge. Windowing conceptsclipping introduction brute force cohensutherland clipping algorithmarea clipping sutherlandhodgman area clipping algorithm 2. A scene is made up of a collection of objectsspecified in world coordinates world coordinates 3. Polygon clipping algorithm by sutherland and hodgeman c program get link.
Sutherland and hodgman s polygon clipping algorithm uses a divideandconquer strategy. The sutherland hodgman algorithm is used for clipping polygons. 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. In computer graphics and games development, polygons are clipped based on a window, which may be. Line and polygon clipping michtom school of computer science. A rendering algorithm only draws pixels in the intersection between the clip region and the scene model. Its a basic operation in creating graphic output of all kinds. A polygon can also be clipped by specifying the clipping window. This is achieved by processing all polygon vertices against each clip rectangle boundary in turn. Computer graphics useful for computer science students, nta net, set, trb polytechnique lecturer for computer science and it, engineering college assistant professor for computer science and it. Sutherland hodgeman polygon clipping algorithm is used for polygon clipping. An algorithm that clips a polygon is rather complex.
Two parallel methods for polygon clipping request pdf. An efficient algorithm for line and polygon clipping. Clip a polygon by successively clipping against each infinite clip edge after each clipping a new set of vertices is produced. The laingbarsky algorithm 1983 is a good deal more complicated, but in certain cases fewer intersections need to be calculated than for sutherland hodgman. First the polygon is clipped against the left edge of the polygon window to get new vertices of the. The output of a polygon clipper should be a sequence of vertices that define the clipped polygon boundaries. These algorithms are able to clip polygons against ir regular convex planefaced volumes in three dimensions. It spendsologp time on each edge of the clipped polygon, wherep is the number of window edges, while the sutherlandhodgman algorithm spendsop time. Feb 14, 2017 poligon clipping sutherland hodgeman algorithm in hindi computer graphics. It allows clipping of a subject or candidate polygon by an arbitrarily shaped clipping polygonarearegion. Pdf polygon clipping and polygon reconstruction researchgate. Use the sketches provide to show the intermediate clipping result of the sutherland hodgman algorithm please follow strictly algorithm given in our lecture.
Sutherlandhodgman polygon clipping algorithm duration. Weiler atherton polygon clipping algorithm geeksforgeeks. Sutherlandhodgeman algorithm a divideandconquer strategy. Consider the following polygon and clipping window. Weiler atherton polygon clipping algorithm is an algorithm made to allow clipping of even concave algorithms to be possible. This is algorithm is used to clip the polygon which lies inside the window boundary. In computer graphics, parametric cubic curves are predominantly used for drawing smooth. Computer graphics sutherlandhodgeman polygon clipping. Clips convex or concave polygons against convex ones.
Theoretical and experimental analyses show that the. The simple problem is to clip a polygon against a single infinite clip edge. The sutherlandhodgman algorithm clips a polygon against all edges of the clipping region in turn. In polygon clipping, we use an algorithm that generates one or more closed areas that are then scan converted for the appropriate area fill. Let me explain the algorithm of sutherlandhodgman using the above situation. Clipping any procedure which identifies that portion of a picture which is either inside or outside a picture is referred toas a clipping algorithm or clipping. Computer graphics i polygon clipping and filling week 3, lecture 5 david breen, william regli and maxim peysakhov. Computer graphics 6 computer graphics is an art of drawing pictures on computer screens with the help of programming. Sutherlandhodgeman polygon clipping this program is for implementing sutherlandhodgeman polygon clipping. Microprocessor 9 artificial intelligence 8 mobile communication and computing 8 computer graphics 7 digital signal processing 6 java me 6 python 6 soft computing 6 network technologies 5 data warehousing and mining. Sutherland hodgman polygon clipping pseudo code for sutherl. May 19, 2011 sutherland hodgeman polygon clipping the algorithm begins with an input list of all vertices in the subject polygon.
Line and polygon clipping michtom school of computer. Clip polygon pto clipping edge foreachedge in polygon p check clipping cases there are 4 case 1. Application of sutherland hodgman polygon clipping. It is used in the areas like computer graphics, games development and others where clipping of polygon is needed.
Sutherland and hodgmans polygonclipping algorithm uses a divideandconquer strategy. We can correctly clip a polygon by processing the polygon boundary as whole each window edge. Consider each edge e of clipping area and do following. The task is to clip polygon edges using the sutherlandhodgman algorithm. Cohen sutherland and cyrusbeck line clipping algorithms. Explain weiler atherton polygon clipping algorithm in detail.
The code snippet seems to be taken directly from the corresponding wikipedia article. Clipping polygon clipping, sutherlandhodgeman clipping. 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. A polygon clipping algorithm receives a polygon and a clipping window as input. 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. Sutherlandhodgeman polygon clipping programs and notes. To associate your repository with the polygonclippingalgorithm topic, visit.
Sutherlandhodgeman polygon clipping algorithm c program. It is a primitive operation in many fields such as geographic information systems gis, computer graphics and vlsi cad. 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. Program to implement sutherlandhodgeman polygon clipping. Explain sutherland hodgeman algorithm for polygon clipping.
Computer graphics polygon clipping and filling week 3, lecture 5 david breen, william regliand maxim peysakhov department of computer science drexel university 1 2 outline polygon clipping sutherlandhodgman, weileratherton polygon filling. That article explains the algorithm and it also explains the code. Computer graphics polygon clipping and filling week 3, lecture 5 david breen, william regliand maxim peysakhov department of computer science drexel university 1 2 outline polygon clipping sutherland hodgman, weileratherton polygon filling. Clipping polygons the sutherlandhodgman algorithm clipping polygons would seem to be quite complex. Sutherlandhodgeman polygon clipping programs and notes for mca. In other words, we can say that computer graphics is a rendering tool for the generation and manipulation of. Mar 24, 2017 65 sutherland hodgeman polygon clipping algorithm in computer graphics in hindi ugc net gate psu duration. An implementation of the sutherlandhodgman algorithm used for clipping polygons in c. Sutherlandhodgman polygonclipping algorithm right clip boundary bottom clip boundary left clip boundary top clip boundary idea. Windowing conceptsclipping introduction brute force cohen sutherland clipping algorithmarea clipping sutherland hodgman area clipping algorithm 2. Sutherlandhodgman polygon clipping algorithm subproblem. 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.