polygon poster

Decomposing polygons with GPC(Owed by: Spring Night rain Http://blog.csdn.net/chunyexiyu reprint please indicate the source)Gpc:generic Polygon ClipperGPC supports decomposition polygon, polygon differential set, intersection, XOR, and setGpc_diff,/* difference */Gpc_int,/* intersection */Gpc_xor,/* Exclusive or */Gpc_union/* UNION */Use is more efficient, but be

Method One: Green formulaThe green formula reveals the relationship between the double integral of the planar area and the line integral on the closed curve .where L + indicates a positive boundary curve along a closed area.And by the derivation process of the green formula we know:If L=-y here, the (1) formula is guaranteed to be constant in the area and equal to the area of the closed area.Similarly, m=x can also guarantee (2) that the formula is constant in the area and equal to the area of

In the process of drawing with OpenGL, since OpenGL does not support direct drawing of concave polygon, we usually need to first convert the concave polygon into a group of triangles with a triangular Polygon Algorithm 1) use a one-way cyclic linked list to save the polygon vertices and calculate the convex and conca

Easy to view and reprint 1. How to determine whether a polygon is clockwise or counterclockwiseFor a convex polygon, you only need to calculate a certain point.Cross Product = (Xi-XI-1), (Yi-Yi-1) x (XI + 1-xi), (yi + 1-yi ))= (Xi-XI-1) * (yi + 1-yi)-(Yi-Yi-1) * (XI + 1-xi) If the value of the preceding formula is positive, it is counter-clockwise. If it is negative, it is clockwise. For a general simple

Original works can be reprinted. During reprinting, you must mark the original source, author information, and this statement in hyperlink form. Otherwise, legal liability will be held. Http://yarin.blog.51cto.com/1130898/380265 Lesson 2: Polygon Your first polygon: Based on the first tutorial, we added a triangle and a quadrilateral. You may think this is simple, but you have taken a big step to know tha

Topic Meaning:An n-shaped N-vertex is given to find the coordinate of the center of gravity of the N-side shape.http://acm.hdu.edu.cn/showproblem.php?pid=1115Topic Analysis:/*** Source: http://blog.csdn.net/ysc504/article/details/8812339*① quality centered on vertices* N Vertex coordinates (xi,yi), MI in mass, center of gravity* X =∑ (XIXMI)/∑mi* Y =∑ (YIXMI)/∑mi* Specifically, if the quality of each point is the same, then* X =∑xi/n* Y =∑yi/n*② Uniform mass Distribution* Specially, the quality

Low polygon (low-poly) font design is the latest and most popular design trend. The low polygon font design is based primarily on a 3D mesh with a small number of polygons, combined with some rendering techniques and lighting effects, making these grids look like paper crafts or origami. Low-polygon is usually required to use 3D software, but this tutorial will

A friend is doing map-related programs, the requirements of the program is: There are a lot of points on the map, stored in the database, input is a polygon, output is contained in this polygon point. A friend discovers that there is a function in Oracle that solves this problem: We then learned about the Oracle spatial API to implement the query functionality. --Create TABLE t2 (ID number, location sdo_geo

The problem of judging convex polygon by vector fork multiplication I'm doing a problem, the title is to give the coordinates of several points in a counter-clockwise order, to find out whether the polygon is concave or convex. I saw a formula on the Internet: Three points on the plane: P1 (x1,y1), p2 (x2,y2), P3 (X3,Y3) S (p1,p2,p3) = (x1-x3) * (y2-y3)-(X2-X3) * (Y1-Y3) If s>0 indicates that these

Rotational painting Time Limit: 2000/1000 MS (Java/others) memory limit: 32768/32768 K (Java/Others)Total submission (s): 2498 accepted submission (s): 702Problem descriptionjosh Lyman is a gifted painter. one of his great works is a glass painting. he creates some well-designed lines on one side of a thick and polygonal glass, and renders it by some special dyes. the most fantastic thing is that it can generate different meaningful paintings by rotating the glass. this method of design is calle

Link: http://acm.sgu.ru/problem.php? Contest = 0 problem = 253 http://acm.hust.edu.cn/vjudge/contest/view.action? Cid = 27464 # Problem/a253. Theodore roosevelttime limit per test: 0.5 sec. Memory limit per test: 65536 kbinput: Standard Output: Standard Danger! Sudden attack on Russia! These are Americans "again", but this time they are serious. giant aircraft-carrier "Theodore Roosevelt" is entering the Baltic Sea. at one o 'clock American aircraft launched from the carrier bombed Petrozavodsk

This article describes in detail the structural relationship between the line, multiple line segments, and polygon in ArcGIS. In the definition of ArcGIS, the class structure view of the Line Section is as follows: You can intuitively see its structural relationship.I. line segments (isegment) The line segments in ArcGIS inherit from isegment and are divided into four types. Ibeziercurve, iline, icirculararc, and iellipticarc ). They only have two en

add points, lines, and polygon elements from the original ArcGIS engine//Draw pointsIPoint pt = axmapcontrol1.tomappoint (e.x, e.y);imarkerelement pmarkerelement = new Markerelementclass ();ielement pelement = pmarkerelement as ielement;pelement.geometry = pt;Igraphicscontainer Pgraphicscontainer = PMap as Igraphicscontainer;pgraphicscontainer.addelement ((ielement) pmarkerelement, 0);Pactiveview.refresh (); //Draw lineigeometry polyline = Axmapcontro

[Getting started with WebGL] 15th, color the polygon (specify the vertex color), and webgl Vertex Note: The article is translated from http://wgld.org/, the original author shanbenya (doxas). If I have additional instructions in the article, I will add [lufy:]. In addition, the research on webgl is not in-depth enough, and some professional words are required, if the translation is incorrect, please correct me. Running result of this demoIncrease th

See the book "algorithm design and analysis" Wang Xiaodong Dynamic Planning 1. problem description (Note: it is the sum of weights of all triangles, not the sum of weights of edges and chords) 2. analysis 3. encoding implementation :/** * @ Author: Hu Jiawei * @ Createtime: 12:31:16 * @ Description: optimal triangular division of a convex polygon. */ PackageEx2; Public ClassTriangulation { Private IntN; // n PolygonPrivate Int[] [] Weight; // edge we

1. Add a site Coordinates (For calculating the area of the last tysen polygon, the coordinates here Format Only XY coordinates are allowed. Only projection coordinates can be selected. System )2. Export the vertex layer as SHP File (Right-click the layer data \ export data)Use Analysis tools \ proximity \ create Thiessen polygonss to divide the tysen polygon (note that Environment Settings \ General Setting

Recently, when I was doing box2dweb development, I wanted to write a function to create a positive polygon. However, due to my knowledge, I drew it on the draft paper and thought about it for a morning and didn't work out any good methods. Later, when I turned the drawer, I found out one of my brother's old paintings that painted an elliptical image with a concentric circle. When I saw this painting, I couldn't help thinking that the elliptic is not a

Lifting the stone Time Limit: 2000/1000 MS (Java/others) memory limit: 65536/32768 K (Java/Others)Total submission (s): 5370 accepted submission (s): 2239Problem descriptionthere are eclipsecret openings in the floor which are covered by a big heavy stone. when the stone is lifted up, a special mechanic detects this and activates initialize ONED arrows that are shot near the opening. the only possibility is to lift the stone very slowly and carefully. the ACM team must connect a rope to the ston

This is a half-plane of the naked problem, the first half-plane to write, just say I half-plane cross understanding it.The so-called half-plane intersection, is to find a large pile of two of yuan an inequality of the intersections, and each two yuan of the solution set of an inequality can be seen in a straight line above or below the standard equation of the contact line can be obtained. So these inequalities can be converted to some half-plane, which is half-plane intersection.The semi-planar

Mysql checks whether a point falls into the polygon bitsCN.com Mysql checks whether a vertex falls within the polygon. For geospatial data, it is often necessary to deal with the association between two spatial data. There are many ways to handle this by writing program algorithms or calling the corresponding functions in the database. In the mysql database. First, create a simple geographic data table,