C# Vertices.isSimple方法代码示例

		/// <summary>
		/// Implements "A new algorithm for Boolean operations on general polygons" 
		/// available here: http://liama.ia.ac.cn/wiki/_media/user:dong:dong_cg_05.pdf
		/// Merges two polygons, a subject and a clip with the specified operation. Polygons may not be 
		/// self-intersecting.
		/// 
		/// Warning: May yield incorrect results or even crash if polygons contain collinear points.
		/// </summary>
		/// <param name="subject">The subject polygon.</param>
		/// <param name="clip">The clip polygon, which is added, 
		/// substracted or intersected with the subject</param>
		/// <param name="clipType">The operation to be performed. Either
		/// Union, Difference or Intersection.</param>
		/// <param name="error">The error generated (if any)</param>
		/// <returns>A list of closed polygons, which make up the result of the clipping operation.
		/// Outer contours are ordered counter clockwise, holes are ordered clockwise.</returns>
		static List<Vertices> execute( Vertices subject, Vertices clip, PolyClipType clipType, out PolyClipError error )
		{
			Debug.Assert( subject.isSimple() && clip.isSimple(), "Non simple input! Input polygons must be simple (cannot intersect themselves)." );

			// Copy polygons
			Vertices slicedSubject;
			Vertices slicedClip;
			// Calculate the intersection and touch points between
			// subject and clip and add them to both
			calculateIntersections( subject, clip, out slicedSubject, out slicedClip );

			// Translate polygons into upper right quadrant
			// as the algorithm depends on it
			Vector2 lbSubject = subject.getAABB().lowerBound;
			Vector2 lbClip = clip.getAABB().lowerBound;
			Vector2 translate;
			Vector2.Min( ref lbSubject, ref lbClip, out translate );
			translate = Vector2.One - translate;
			if( translate != Vector2.Zero )
			{
				slicedSubject.translate( ref translate );
				slicedClip.translate( ref translate );
			}

			// Enforce counterclockwise contours
			slicedSubject.forceCounterClockWise();
			slicedClip.forceCounterClockWise();

			List<Edge> subjectSimplices;
			List<float> subjectCoeff;
			List<Edge> clipSimplices;
			List<float> clipCoeff;
			// Build simplical chains from the polygons and calculate the
			// the corresponding coefficients
			calculateSimplicalChain( slicedSubject, out subjectCoeff, out subjectSimplices );
			calculateSimplicalChain( slicedClip, out clipCoeff, out clipSimplices );

			List<Edge> resultSimplices;

			// Determine the characteristics function for all non-original edges
			// in subject and clip simplical chain and combine the edges contributing
			// to the result, depending on the clipType
			calculateResultChain( subjectCoeff, subjectSimplices, clipCoeff, clipSimplices, clipType,
								 out resultSimplices );

			List<Vertices> result;
			// Convert result chain back to polygon(s)
			error = buildPolygonsFromChain( resultSimplices, out result );

			// Reverse the polygon translation from the beginning
			// and remove collinear points from output
			translate *= -1f;
			for( int i = 0; i < result.Count; ++i )
			{
				result[i].translate( ref translate );
				SimplifyTools.collinearSimplify( result[i] );
			}
			return result;
		}