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Editor/Util/Triangulate.h

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+// ** THIS IS A CODE SNIPPET WHICH WILL EFFICIEINTLY TRIANGULATE ANY
+// ** POLYGON/CONTOUR (without holes) AS A STATIC CLASS.  THIS SNIPPET
+// ** IS COMPRISED OF 3 FILES, TRIANGULATE.H, THE HEADER FILE FOR THE
+// ** TRIANGULATE BASE CLASS, TRIANGULATE.CPP, THE IMPLEMENTATION OF
+// ** THE TRIANGULATE BASE CLASS, AND TEST.CPP, A SMALL TEST PROGRAM
+// ** DEMONSTRATING THE USAGE OF THE TRIANGULATOR.  THE TRIANGULATE
+// ** BASE CLASS ALSO PROVIDES TWO USEFUL HELPER METHODS, ONE WHICH
+// ** COMPUTES THE AREA OF A POLYGON, AND ANOTHER WHICH DOES AN EFFICENT
+// ** POINT IN A TRIANGLE TEST.
+// ** SUBMITTED BY JOHN W. RATCLIFF (jratcliff@verant.com) July 22, 2000
+
+/**********************************************************************/
+/************ HEADER FILE FOR TRIANGULATE.H ***************************/
+/**********************************************************************/
+
+
+#ifndef TRIANGULATE_H
+
+#define TRIANGULATE_H
+
+/*****************************************************************/
+/** Static class to triangulate any contour/polygon efficiently **/
+/** You should replace Vector2d with whatever your own Vector   **/
+/** class might be.  Does not support polygons with holes.      **/
+/** Uses STL vectors to represent a dynamic array of vertices.  **/
+/** This code snippet was submitted to FlipCode.com by          **/
+/** John W. Ratcliff (jratcliff@verant.com) on July 22, 2000    **/
+/** I did not write the original code/algorithm for this        **/
+/** this triangulator, in fact, I can't even remember where I   **/
+/** found it in the first place.  However, I did rework it into **/
+/** the following black-box static class so you can make easy   **/
+/** use of it in your own code.  Simply replace Vector2d with   **/
+/** whatever your own Vector implementation might be.           **/
+/*****************************************************************/
+
+
+#include <vector>  // Include STL vector class.
+
+// Typedef an STL vector of vertices which are used to represent
+// a polygon/contour and a series of triangles.
+typedef std::vector< Vec3 > Vector2dVector;
+
+
+class CTriangulate
+{
+public:
+
+  // triangulate a contour/polygon, places results in STL vector
+  // as series of triangles.
+  static bool Process(const Vector2dVector &contour,
+                      Vector2dVector &result);
+
+  // compute area of a contour/polygon
+  static float Area(const Vector2dVector &contour);
+
+  // decide if point Px/Py is inside triangle defined by
+  // (Ax,Ay) (Bx,By) (Cx,Cy)
+  static bool InsideTriangle(float Ax, float Ay,
+                      float Bx, float By,
+                      float Cx, float Cy,
+                      float Px, float Py);
+
+
+private:
+  static bool Snip(const Vector2dVector &contour,int u,int v,int w,int n,int *V);
+
+};
+
+
+#endif
+