凹多边形

Secondly, some foundational arithmetic such as the division of concave polygon, the polygons boolean operation, the transform from circle to polygon, the pick-up of model top surface were designed particularly based on OpenGL.

然后，基于图形库OpenGL完成了包括凹多边形的分割、多边形的布尔运算、圆的多边形转化、模型上表面获取等基础算法；并针对已建模工艺设计了相应的仿真算法。

For example, OpenGL does not directly support drawing a concave polygon.

举例来说，OpenGL的不直接支持画凹多边形。

Tess of the method used in OpenGL draw concave polygon, called a very simple and saved a lot of the complexity of the work of the test.

详细说明：用Tess的方法实现OpenGL中画凹多边形，调用非常简单，而且省去了大量的复杂工作，测试通过。

We provided an concise, fast and accurate method based on point-governed region for the problem, and resolved a special case of hole and concave polygon in the path.

本文就该课题提出了一种基于点辖域的简洁、快速、准确的方法，并解决了空洞和凹多边形等特殊情况，有效的解决了该问题夫妻。

OpenGL rendering of the stars procedures, is a concave polygon.

详细说明： OpenGL绘制的星星程序，是一个凹多边形。

Data stucture of the model is also put forward. On account of OpenGL cant paint concave polygon, a new method named partition of beenline is brought forward.

在对建筑物封顶时，针对OpenGL不能直接填充凹多边形运用了一种直线剖分的方法来实现OpenGL对凹多边形的填充。

A new polygon filling method——polygon trapezoidal decomposition filling method——is put forward and realized. An analytical comparing between its time complexity and that of the classical methods shows that it is faster than scan-line algorithm in the case of complex concave polygon.

提出了一条新的多边形填充思路——多边形梯形网格剖分填充法，实现了该算法并将其时间复杂度与经典的有序边表算法进行了比较，说明该方法在复杂的凹多边形情况下处理速度较有序边表快。

The implementation process of the algorithm is as follows: First, the scanning lines of each contour are generated, while the contour's shape can be divided into convex polygon and concave polygon, and the generating process of the scanning lines of each contour needs special treatments .

首先依次生成每个轮廓的轮廓扫描线，由于轮廓形状可能为凸多边形也可能为凹多边形，所以在生成各轮廓的扫描线时要增加一些特殊处理操作。

This algorithm can be used for both the convex and the concave contours.

该算法同时适用于凸多边形和凹多边形，并具有较好的区分度和匹配准确性。

Convex polygon, which means that if a portal turns out to be concave, we will generate several

味着如果Portal 是一个凹多边形，我们必须将其切分为数个凸多边形。

Means the parent directory, so this command means to execute "toolchain.sh," which is in the current directory.

代表父目录，所以这个命令就是执行当前目录下的"toolchain.sh"。

Yes,In fact,I'm on our city ream.

是的。事实上我是我们市队的。