added Box2/3, Triangle2, 2D Line/Seg Tri and Tri/Tri intersection, 3D…

… Ray/Line/Seg Box intersection

geometry3Sharp.csproj

@@ -131,9 +131,19 @@
     <Compile Include="math\Interval1d.cs" />
     <Compile Include="curve\GeneralPolygon2d.cs" />
     <Compile Include="curve\EllipseArc2.cs" />
+    <Compile Include="math\Triangle2.cs" />
+    <Compile Include="intersection\IntrLine2Triangle2.cs" />
+    <Compile Include="intersection\IntrSegment2Triangle2.cs" />
+    <Compile Include="intersection\IntrTriangle2Triangle2.cs" />
+    <Compile Include="math\Box3.cs" />
+    <Compile Include="math\Box2.cs" />
+    <Compile Include="intersection\IntrLine3Box3.cs" />
+    <Compile Include="intersection\IntrSegment3Box3.cs" />
+    <Compile Include="intersection\IntrRay3Box3.cs" />
   </ItemGroup>
   <ItemGroup>
     <Folder Include="interfaces\" />
+    <Folder Include="intersection\" />
   </ItemGroup>
   <ItemGroup>
     <None Include="LICENSE" />

intersection/IntrLine2Triangle2.cs

@@ -0,0 +1,194 @@
+using System;
+
+namespace g3 
+{
+	// ported from WildMagic5 
+	public class IntrLine2Triangle2
+	{
+		Line2d line;
+		public Line2d Line
+		{
+			get { return line; }
+			set { line = value; Result = IntersectionResult.NotComputed; }
+		}
+
+		Triangle2d triangle;
+		public Triangle2d Triangle
+		{
+			get { return triangle; }
+			set { triangle = value; Result = IntersectionResult.NotComputed; }
+		}
+
+		public int Quantity = 0;
+		public IntersectionResult Result = IntersectionResult.NotComputed;
+		public IntersectionType Type = IntersectionType.Empty;
+
+		public bool IsSimpleIntersection {
+			get { return Result == IntersectionResult.Intersects && Type == IntersectionType.Point; }
+		}
+
+
+		public Vector2d Point0;
+		public Vector2d Point1;
+		public double Param0;
+		public double Param1;
+
+
+		public IntrLine2Triangle2(Line2d l, Triangle2d t)
+		{
+			line = l; triangle = t;
+		}
+
+
+		public IntrLine2Triangle2 Compute()
+		{
+			Find();
+			return this;
+		}
+
+
+		public bool Find()
+		{
+			if (Result != IntersectionResult.NotComputed)
+				return (Result == IntersectionResult.Intersects);
+
+			// [RMS] if either line direction is not a normalized vector, 
+			//   results are garbage, so fail query
+			if ( line.Direction.IsNormalized == false )  {
+				Type = IntersectionType.Empty;
+				Result = IntersectionResult.InvalidQuery;
+				return false;
+			}
+
+			Vector3d dist = Vector3d.Zero;
+			Vector3i sign = Vector3i.Zero;
+			int positive = 0, negative = 0, zero = 0;
+			TriangleLineRelations(line.Origin, line.Direction, triangle,
+			              ref dist, ref sign, ref positive, ref negative, ref zero);
+
+			if (positive == 3 || negative == 3) {
+				// No intersections.
+				Quantity = 0;
+				Type = IntersectionType.Empty;
+			} else {
+				Vector2d param = Vector2d.Zero;
+				GetInterval(line.Origin, line.Direction, triangle, dist, sign, ref param);
+
+				Intersector1 intr = new Intersector1(param[0], param[1], -double.MaxValue, +double.MaxValue);
+				intr.Find();
+
+				Quantity = intr.NumIntersections;
+				if (Quantity == 2) {
+					// Segment intersection.
+					Type = IntersectionType.Segment;
+					Param0 = intr.GetIntersection(0);
+					Point0 = line.Origin + Param0*line.Direction;
+					Param1 = intr.GetIntersection(1);
+					Point1 = line.Origin + Param1*line.Direction;
+				} else if (Quantity == 1) {
+					// Point intersection.
+					Type = IntersectionType.Point;
+					Param0 = intr.GetIntersection(0);
+					Point0 = line.Origin + Param0*line.Direction;
+				} else {
+					// No intersections.
+					Type = IntersectionType.Empty;
+				}
+			}
+
+			Result = (Type != IntersectionType.Empty) ?
+				IntersectionResult.Intersects : IntersectionResult.NoIntersection;
+			return (Result == IntersectionResult.Intersects);
+		}
+
+
+
+		public static void TriangleLineRelations (
+			Vector2d origin, Vector2d direction,
+			Triangle2d tri, ref Vector3d dist, ref Vector3i sign,
+			ref int positive, ref int negative, ref int zero)
+		{
+			positive = 0;
+			negative = 0;
+			zero = 0;
+			for (int i = 0; i < 3; ++i) {
+				Vector2d diff = tri[i] - origin;
+				dist[i] = diff.DotPerp(direction);
+				if (dist[i] > MathUtil.ZeroTolerance)
+				{
+					sign[i] = 1;
+					++positive;
+				}
+				else if (dist[i] < -MathUtil.ZeroTolerance)
+				{
+					sign[i] = -1;
+					++negative;
+				}
+				else
+				{
+					dist[i] = 0.0;
+					sign[i] = 0;
+					++zero;
+				}
+			}
+		}
+
+
+
+		public static void GetInterval (Vector2d origin, Vector2d direction, Triangle2d tri,
+		                  Vector3d dist, Vector3i sign, ref Vector2d param)
+		{
+			// Project triangle onto line.
+			Vector3d proj = Vector3d.Zero;
+			int i;
+			for (i = 0; i < 3; ++i) {
+				Vector2d diff = tri[i] - origin;
+				proj[i] = direction.Dot(diff);
+			}
+
+			// Compute transverse intersections of triangle edges with line.
+			double numer, denom;
+			int i0, i1, i2;
+			int quantity = 0;
+			for (i0 = 2, i1 = 0; i1 < 3; i0 = i1++) {
+				if (sign[i0]*sign[i1] < 0) {
+					if ( quantity >= 2 )
+						throw new Exception("IntrLine2Triangle2.GetInterval: too many intersections!");
+					numer = dist[i0]*proj[i1] - dist[i1]*proj[i0];
+					denom = dist[i0] - dist[i1];
+					param[quantity++] = numer/denom;
+				}
+			}
+
+			// Check for grazing contact.
+			if (quantity < 2) {
+				for (i0 = 1, i1 = 2, i2 = 0; i2 < 3; i0 = i1, i1 = i2++) {
+					if (sign[i2] == 0) {
+						if ( quantity >= 2 )
+							throw new Exception("IntrLine2Triangle2.GetInterval: too many intersections!");	
+						param[quantity++] = proj[i2];
+					}
+				}
+			}
+
+			// Sort.
+			if ( quantity < 1 )
+				throw new Exception("IntrLine2Triangle2.GetInterval: need at least one intersection");
+			if (quantity == 2)
+			{
+				if (param[0] > param[1])
+				{
+					double save = param[0];
+					param[0] = param[1];
+					param[1] = save;
+				}
+			}
+			else
+			{
+				param[1] = param[0];
+			}
+		}
+
+
+	}
+}