144 lines
4.8 KiB
C#
144 lines
4.8 KiB
C#
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namespace TriangleNet.Geometry
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{
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using System;
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using TriangleNet.Meshing;
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public static class ExtensionMethods
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{
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#region IPolygon extensions
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/// <summary>
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/// Triangulates a polygon.
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/// </summary>
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public static IMesh Triangulate(this IPolygon polygon)
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{
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return (new GenericMesher()).Triangulate(polygon, null, null);
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}
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/// <summary>
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/// Triangulates a polygon, applying constraint options.
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/// </summary>
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/// <param name="options">Constraint options.</param>
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public static IMesh Triangulate(this IPolygon polygon, ConstraintOptions options)
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{
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return (new GenericMesher()).Triangulate(polygon, options, null);
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}
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/// <summary>
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/// Triangulates a polygon, applying quality options.
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/// </summary>
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/// <param name="quality">Quality options.</param>
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public static IMesh Triangulate(this IPolygon polygon, QualityOptions quality)
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{
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return (new GenericMesher()).Triangulate(polygon, null, quality);
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}
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/// <summary>
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/// Triangulates a polygon, applying quality and constraint options.
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/// </summary>
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/// <param name="options">Constraint options.</param>
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/// <param name="quality">Quality options.</param>
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public static IMesh Triangulate(this IPolygon polygon, ConstraintOptions options, QualityOptions quality)
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{
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return (new GenericMesher()).Triangulate(polygon, options, quality);
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}
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/// <summary>
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/// Triangulates a polygon, applying quality and constraint options.
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/// </summary>
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/// <param name="options">Constraint options.</param>
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/// <param name="quality">Quality options.</param>
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/// <param name="triangulator">The triangulation algorithm.</param>
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public static IMesh Triangulate(this IPolygon polygon, ConstraintOptions options, QualityOptions quality,
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ITriangulator triangulator)
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{
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return (new GenericMesher(triangulator)).Triangulate(polygon, options, quality);
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}
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#endregion
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#region Rectangle extensions
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#endregion
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#region ITriangle extensions
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/// <summary>
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/// Test whether a given point lies inside a triangle or not.
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/// </summary>
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/// <param name="p">Point to locate.</param>
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/// <returns>True, if point is inside or on the edge of this triangle.</returns>
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public static bool Contains(this ITriangle triangle, Point p)
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{
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return Contains(triangle, p.X, p.Y);
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}
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/// <summary>
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/// Test whether a given point lies inside a triangle or not.
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/// </summary>
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/// <param name="x">Point to locate.</param>
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/// <param name="y">Point to locate.</param>
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/// <returns>True, if point is inside or on the edge of this triangle.</returns>
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public static bool Contains(this ITriangle triangle, double x, double y)
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{
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var t0 = triangle.GetVertex(0);
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var t1 = triangle.GetVertex(1);
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var t2 = triangle.GetVertex(2);
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// TODO: no need to create new Point instances here
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Point d0 = new Point(t1.X - t0.X, t1.Y - t0.Y);
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Point d1 = new Point(t2.X - t0.X, t2.Y - t0.Y);
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Point d2 = new Point(x - t0.X, y - t0.Y);
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// crossproduct of (0, 0, 1) and d0
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Point c0 = new Point(-d0.Y, d0.X);
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// crossproduct of (0, 0, 1) and d1
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Point c1 = new Point(-d1.Y, d1.X);
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// Linear combination d2 = s * d0 + v * d1.
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//
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// Multiply both sides of the equation with c0 and c1
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// and solve for s and v respectively
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//
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// s = d2 * c1 / d0 * c1
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// v = d2 * c0 / d1 * c0
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double s = DotProduct(d2, c1) / DotProduct(d0, c1);
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double v = DotProduct(d2, c0) / DotProduct(d1, c0);
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if (s >= 0 && v >= 0 && ((s + v) <= 1))
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{
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// Point is inside or on the edge of this triangle.
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return true;
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}
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return false;
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}
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public static Rectangle Bounds(this ITriangle triangle)
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{
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var bounds = new Rectangle();
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for (int i = 0; i < 3; i++)
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{
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bounds.Expand(triangle.GetVertex(i));
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}
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return bounds;
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}
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#endregion
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#region Helper methods
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internal static double DotProduct(Point p, Point q)
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{
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return p.X * q.X + p.Y * q.Y;
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}
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#endregion
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}
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}
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