toxi.geom.util
Class TriangleMesh

java.lang.Object
  toxi.geom.util.TriangleMesh

public class TriangleMesh
extends java.lang.Object

A class to dynamically build, manipulate & export triangle meshes. Meshes are build face by face. The class automatically re-uses existing vertices and can create smooth vertex normals. Vertices and faces are directly accessible for speed & convenience.

Nested Class Summary

static class	TriangleMesh.Face
static class	TriangleMesh.Vertex

Field Summary

java.util.ArrayList<TriangleMesh.Face>	faces Face list
java.lang.String	name Mesh name
java.util.LinkedHashMap<Vec3D,TriangleMesh.Vertex>	vertices Vertex buffer & lookup index when adding new faces

Constructor Summary

TriangleMesh()

TriangleMesh(java.lang.String name)
Creates a new mesh instance with an initial buffer size of 1000 vertices & 3000 faces.

TriangleMesh(java.lang.String name, int numV, int numF)
Creates a new mesh instance with the given initial buffer sizes.

Method Summary

void	addFace(Vec3D a, Vec3D b, Vec3D c) Adds the given 3 points as triangle face to the mesh.
AABB	center(Vec3D origin) Centers the mesh around the given pivot point (the centroid of its AABB).
void	clear() Clears all counters, and vertex & face buffers.
void	computeVertexNormals() Computes the smooth vertex normals for the entire mesh.
TriangleMesh	copy() Creates a deep clone of the mesh.
AABB	getBoundingBox() Computes & returns the axis-aligned bounding box of the mesh.
Sphere	getBoundingSphere() Computes & returns the bounding sphere of the mesh.
Vec3D	getCentroid() Computes the mesh centroid, the average position of all vertices.
int[]	getFacesAsArray() Builds an array of vertex indices of all faces.
float[]	getMeshAsVertexArray() Creates an array of unravelled vertex coordinates for all faces using a stride setting of 3, resulting in a gap-less serialized version of all mesh vertex coordinates.
float[]	getMeshAsVertexArray(float[] verts, int offset, int stride) Creates an array of unravelled vertex coordinates for all faces.
int	getNumFaces() Returns the number of triangles used.
int	getNumVertices() Returns the number of actual vertices used (unique vertices).
float[]	getUniqueVerticesAsArray()
float[]	getVertexNormalsAsArray()
float[]	getVertexNormalsAsArray(float[] normals, int offset, int stride) Creates an array of unravelled vertex normal coordinates for all faces.
void	saveAsOBJ(OBJWriter obj) Saves the mesh as OBJ format by appending it to the given mesh OBJWriter instance.
void	saveAsOBJ(java.lang.String path) Saves the mesh as OBJ format to the given file path.
void	saveAsRaw(java.lang.String fileName) Saves the mesh in a simple, proprietary compact binary format written using the standard DataOutputStream methods.
void	saveAsSTL(java.lang.String fileName) Saves the mesh as binary STL format to the given file path.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

name

public java.lang.String name

Mesh name

vertices

public final java.util.LinkedHashMap<Vec3D,TriangleMesh.Vertex> vertices

Vertex buffer & lookup index when adding new faces

faces

public final java.util.ArrayList<TriangleMesh.Face> faces

Face list

Constructor Detail

TriangleMesh

public TriangleMesh()

TriangleMesh

public TriangleMesh(java.lang.String name)

Creates a new mesh instance with an initial buffer size of 1000 vertices & 3000 faces.

Parameters:

name - mesh name

TriangleMesh

public TriangleMesh(java.lang.String name,
                    int numV,
                    int numF)

Creates a new mesh instance with the given initial buffer sizes. These numbers are no limits and the mesh can be smaller or grow later on. They're only used to initialise the underlying collections.

Parameters:

name - mesh name

numV - initial vertex buffer size

numF - initial face list size

Method Detail

addFace

public final void addFace(Vec3D a,
                          Vec3D b,
                          Vec3D c)

Adds the given 3 points as triangle face to the mesh. The assumed vertex order is anti-clockwise.

Parameters:

a -

b -

c -

center

public AABB center(Vec3D origin)

Centers the mesh around the given pivot point (the centroid of its AABB). Method also updates & returns the new bounding box.

Parameters:

origin - new centroid or null (defaults to {0,0,0})

clear

public void clear()

Clears all counters, and vertex & face buffers.

computeVertexNormals

public void computeVertexNormals()

Computes the smooth vertex normals for the entire mesh. This method should only be called once in order to avoid disintegration of the normal vectors.

copy

public TriangleMesh copy()

Creates a deep clone of the mesh. The new mesh name will have "-copy" as suffix.

Returns:

new mesh instance

getBoundingBox

public AABB getBoundingBox()

Computes & returns the axis-aligned bounding box of the mesh.

Returns:

bounding box

getBoundingSphere

public Sphere getBoundingSphere()

Computes & returns the bounding sphere of the mesh. The origin of the sphere is the mesh's centroid.

Returns:

bounding sphere

getCentroid

public Vec3D getCentroid()

Computes the mesh centroid, the average position of all vertices.

Returns:

centre point

getFacesAsArray

public int[] getFacesAsArray()

Builds an array of vertex indices of all faces. Each vertex ID corresponds to its position in the vertices HashMap. The resulting array will be 3 times the face count.

Returns:

array of vertex indices

getMeshAsVertexArray

public float[] getMeshAsVertexArray()

Creates an array of unravelled vertex coordinates for all faces using a stride setting of 3, resulting in a gap-less serialized version of all mesh vertex coordinates.

Returns:

float array of vertex coordinates

See Also:

getMeshAsVertexArray(float[], int, int)

getMeshAsVertexArray

public float[] getMeshAsVertexArray(float[] verts,
                                    int offset,
                                    int stride)

Creates an array of unravelled vertex coordinates for all faces. This method can be used to translate the internal mesh data structure into a format suitable for OpenGL Vertex Buffer Objects (by choosing stride=4). The order of the array will be as follows:

• Face 1:
  • Vertex #1
    • x
    • y
    • z
    • [optional empty indices to match stride setting]
  • Vertex #2
    • x
    • y
    • z
    • [optional empty indices to match stride setting]
  • Vertex #3
    • x
    • y
    • z
    • [optional empty indices to match stride setting]
• Face 2:
  • Vertex #1
  • ...etc.

Parameters:

verts - an existing target array or null to automatically create one

offset - start index in arrtay to place vertices

stride - stride/alignment setting for individual coordinates

Returns:

array of xyz vertex coords

getNumFaces

public int getNumFaces()

Returns the number of triangles used.

Returns:

face count

getNumVertices

public int getNumVertices()

Returns the number of actual vertices used (unique vertices).

Returns:

vertex count

getUniqueVerticesAsArray

public float[] getUniqueVerticesAsArray()

getVertexNormalsAsArray

public float[] getVertexNormalsAsArray()

Returns:

array of xyz normal coords

See Also:

getVertexNormalsAsArray(float[], int, int)

getVertexNormalsAsArray

public float[] getVertexNormalsAsArray(float[] normals,
                                       int offset,
                                       int stride)

Creates an array of unravelled vertex normal coordinates for all faces. This method can be used to translate the internal mesh data structure into a format suitable for OpenGL Vertex Buffer Objects (by choosing stride=4). For more detail, please see getMeshAsVertexArray(float[], int, int)

Parameters:

normals - existing float array or null to automatically create one

offset - start index in array to place normals

stride - stride/alignment setting for individual coordinates

Returns:

array of xyz normal coords

See Also:

getMeshAsVertexArray(float[], int, int)

saveAsOBJ

public void saveAsOBJ(OBJWriter obj)

Saves the mesh as OBJ format by appending it to the given mesh OBJWriter instance.

Parameters:

obj -

saveAsOBJ

public void saveAsOBJ(java.lang.String path)

Saves the mesh as OBJ format to the given file path. Existing files will be overwritten.

Parameters:

path -

saveAsRaw

public final void saveAsRaw(java.lang.String fileName)

Saves the mesh in a simple, proprietary compact binary format written using the standard DataOutputStream methods. The format is as follows:

• int: number of vertex coordinates
• float: count times vertice coordinates in x,y,z order
• float: count times vertex normal coordinates in x,y,z order

Parameters:

fileName -

saveAsSTL

public final void saveAsSTL(java.lang.String fileName)

Saves the mesh as binary STL format to the given file path. Existing files will be overwritten.

Parameters:

fileName -

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object