maspack.geometry

Class TriangleTessellator

java.lang.Object

maspack.geometry.TriangleTessellator

public class TriangleTessellator
extends java.lang.Object

Uses the native Triangle code developed by Jonathon Shewchuck to create triangulated 2D meshes. https://www.cs.cmu.edu/~quake/triangle.html Requires a JNI binary library called TriangleJNI.1.6. Since Triangle is free only for non-commercial applications, ArtiSynth does not supply it by default. We can supply this library if you meet the license requirements of Triangle.

Constructor Summary

Constructors

Constructor and Description
TriangleTessellator() Create a new Triangular Tesselator.

Method Summary

Modifier and Type	Method and Description
void	buildFromPoints(double[] coords) Construct a 2D mesh from a set of point coordinates.
void	buildFromPoints(double[] coords, double minAngle) Construct a quality 2D mesh with a minimum angle within any given triangle.
void	buildFromPoints(Point2d[] pnts) Build a mesh from a collection of 2D points.
void	buildFromPoints(Point2d[] pnts, double minAngle) Construct a quality 2D mesh with a minimum angle within any given triangle.
void	buildFromSegmentsAndPoints(double[] pntCoords, int[] segments) Builds a constrained mesh that includes the given 2D line segments.
void	buildFromSegmentsAndPoints(double[] pntCoords, int[] segments, double minAngle) Builds a constrained quality mesh that includes the given 2D line segments, attempting to guarantee a minimum angle within the triangle.
void	buildFromSegmentsAndPoints(Point2d[] pnts, int[] segments) Builds a constrained mesh that includes the given 2D line segments.
void	buildFromSegmentsAndPoints(Point2d[] pnts, int[] segments, double minAngle) Builds a constrained quality mesh that includes the given 2D line segments, attempting to guarantee a minimum angle within the triangle.
void	dispose() Destroy the tessellator
void	finalize()
int	getNumPoints() Number of points in the resulting tessellation
int	getNumTriangles() The number of triangles in the resulting tessellation
double[]	getPointCoords() The 2D coordinates of points in the tesselation, interleaved.
Point2d[]	getPoints() The final 2D points in the tessellation
int[]	getTriangles() Returns the vertex indices of all the triangles in this tessellation.
static void	main(java.lang.String[] args)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TriangleTessellator

public TriangleTessellator()

Create a new Triangular Tesselator. The tesselator does hold state, so should only be used to tesselate one mesh at a time.

Method Detail

buildFromPoints

public void buildFromPoints(Point2d[] pnts)

Build a mesh from a collection of 2D points. The resulting mesh will consist of the convex hull of the set of points.

Parameters:

pnts - points to include in mesh

buildFromPoints

public void buildFromPoints(Point2d[] pnts,
                            double minAngle)

Construct a quality 2D mesh with a minimum angle within any given triangle. Additional points may be added to the mesh to allow for the angle constraint.

Parameters:

pnts - points to include in mesh

minAngle - minimum angle

buildFromPoints

public void buildFromPoints(double[] coords)

Construct a 2D mesh from a set of point coordinates. The coordinates are assumed interleaved, {x0,y0,x1,y1,x2,y2,...}.

Parameters:

coords - set of 2D point coordinates

buildFromPoints

public void buildFromPoints(double[] coords,
                            double minAngle)

Construct a quality 2D mesh with a minimum angle within any given triangle. Additional points may be added to the mesh to allow for the angle constraint. The coordinates are assumed interleaved, {x0,y0,x1,y1,x2,y2,...}.

Parameters:

coords - coordinates of points to include in mesh

minAngle - minimum angle

buildFromSegmentsAndPoints

public void buildFromSegmentsAndPoints(Point2d[] pnts,
                                       int[] segments)

Builds a constrained mesh that includes the given 2D line segments. The segments array includes pairs of indices into the points array. For example, segments={0,1,2,3} would include the two line segments, pnts[0] -> pnts[1], and pnts[2] -> pnts[3].

Parameters:

pnts - points to include in the tesselation

segments - line-segments to include as constraints

buildFromSegmentsAndPoints

public void buildFromSegmentsAndPoints(double[] pntCoords,
                                       int[] segments)

Builds a constrained mesh that includes the given 2D line segments. The segments array includes pairs of indices into the points array. For example, segments={0,1,2,3} would include the two line segments,

• (pntCoords[0],pntCoords[1]) -> (pntCoords[2],pntsCoords[3]), and
• (pntCoords[4],pntCoords[5]) -> (pntCoords[6],pntsCoords[7]).

Parameters:

pntCoords - 2D coordinates of points, interleaved, to include in the tesselation

segments - line-segments to include as constraints

buildFromSegmentsAndPoints

public void buildFromSegmentsAndPoints(Point2d[] pnts,
                                       int[] segments,
                                       double minAngle)

Builds a constrained quality mesh that includes the given 2D line segments, attempting to guarantee a minimum angle within the triangle. The segments array includes pairs of indices into the points array. For example, segments={0,1,2,3} would include the two line segments, pnts[0] -> pnts[1], and pnts[2] -> pnts[3].

Parameters:

pnts - points to include in the tesselation

segments - line-segments to include as constraints

minAngle - minimum angle within any given triangle

buildFromSegmentsAndPoints

public void buildFromSegmentsAndPoints(double[] pntCoords,
                                       int[] segments,
                                       double minAngle)

Builds a constrained quality mesh that includes the given 2D line segments, attempting to guarantee a minimum angle within the triangle. The segments array includes pairs of indices into the points array. For example, segments={0,1,2,3} would include the two line segments,

• (pntCoords[0],pntCoords[1]) -> (pntCoords[2],pntsCoords[3]), and
• (pntCoords[4],pntCoords[5]) -> (pntCoords[6],pntsCoords[7]).

Parameters:

pntCoords - 2D coordinates of points, interleaved, to include in the tesselation

segments - line-segments to include as constraints

minAngle - minimum angle within any given triangle

getTriangles

public int[] getTriangles()

Returns the vertex indices of all the triangles in this tessellation. If idxs is the array returned by this method, then the length of idxs is three times the number of triangles, with the vertex indices of the first triangle given by idxs[0], idxs[1], idxs[2]

The vertices are ordered such that if v0 is the first vertex, v0, v1, and v2 are arranged counter-clockwise

Returns:

vertices for the triangles in this tessellation.

getNumTriangles

public int getNumTriangles()

The number of triangles in the resulting tessellation

Returns:

number of triangles

getNumPoints

public int getNumPoints()

Number of points in the resulting tessellation

Returns:

number of points

getPointCoords

public double[] getPointCoords()

The 2D coordinates of points in the tesselation, interleaved.

Returns:

coordinates of 2D points

getPoints

public Point2d[] getPoints()

The final 2D points in the tessellation

Returns:

2D points

dispose

public void dispose()

Destroy the tessellator

finalize

public void finalize()

Overrides:

finalize in class java.lang.Object

main

public static void main(java.lang.String[] args)