opensim-development – Rev 1
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/* The MIT License
*
* Copyright (c) 2010 Intel Corporation.
* All rights reserved.
*
* Based on the convexdecomposition library from
* <http://codesuppository.googlecode.com> by John W. Ratcliff and Stan Melax.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
using System;
using System.Collections.Generic;
using System.Text;
namespace OpenSim.Region.Physics.ConvexDecompositionDotNet
{
public static class Concavity
{
// compute's how 'concave' this object is and returns the total volume of the
// convex hull as well as the volume of the 'concavity' which was found.
public static float computeConcavity(List<float3> vertices, List<int> indices, ref float4 plane, ref float volume)
{
float cret = 0f;
volume = 1f;
HullResult result = new HullResult();
HullDesc desc = new HullDesc();
desc.MaxFaces = 256;
desc.MaxVertices = 256;
desc.SetHullFlag(HullFlag.QF_TRIANGLES);
desc.Vertices = vertices;
HullError ret = HullUtils.CreateConvexHull(desc, ref result);
if (ret == HullError.QE_OK)
{
volume = computeMeshVolume2(result.OutputVertices, result.Indices);
// ok..now..for each triangle on the original mesh..
// we extrude the points to the nearest point on the hull.
List<CTri> tris = new List<CTri>();
for (int i = 0; i < result.Indices.Count / 3; i++)
{
int i1 = result.Indices[i * 3 + 0];
int i2 = result.Indices[i * 3 + 1];
int i3 = result.Indices[i * 3 + 2];
float3 p1 = result.OutputVertices[i1];
float3 p2 = result.OutputVertices[i2];
float3 p3 = result.OutputVertices[i3];
CTri t = new CTri(p1, p2, p3, i1, i2, i3);
tris.Add(t);
}
// we have not pre-computed the plane equation for each triangle in the convex hull..
float totalVolume = 0;
List<CTri> ftris = new List<CTri>(); // 'feature' triangles.
List<CTri> input_mesh = new List<CTri>();
for (int i = 0; i < indices.Count / 3; i++)
{
int i1 = indices[i * 3 + 0];
int i2 = indices[i * 3 + 1];
int i3 = indices[i * 3 + 2];
float3 p1 = vertices[i1];
float3 p2 = vertices[i2];
float3 p3 = vertices[i3];
CTri t = new CTri(p1, p2, p3, i1, i2, i3);
input_mesh.Add(t);
}
for (int i = 0; i < indices.Count / 3; i++)
{
int i1 = indices[i * 3 + 0];
int i2 = indices[i * 3 + 1];
int i3 = indices[i * 3 + 2];
float3 p1 = vertices[i1];
float3 p2 = vertices[i2];
float3 p3 = vertices[i3];
CTri t = new CTri(p1, p2, p3, i1, i2, i3);
featureMatch(t, tris, input_mesh);
if (t.mConcavity > 0.05f)
{
float v = t.getVolume();
totalVolume += v;
ftris.Add(t);
}
}
SplitPlane.computeSplitPlane(vertices, indices, ref plane);
cret = totalVolume;
}
return cret;
}
public static bool featureMatch(CTri m, List<CTri> tris, List<CTri> input_mesh)
{
bool ret = false;
float neardot = 0.707f;
m.mConcavity = 0;
for (int i = 0; i < tris.Count; i++)
{
CTri t = tris[i];
if (t.samePlane(m))
{
ret = false;
break;
}
float dot = float3.dot(t.mNormal, m.mNormal);
if (dot > neardot)
{
float d1 = t.planeDistance(m.mP1);
float d2 = t.planeDistance(m.mP2);
float d3 = t.planeDistance(m.mP3);
if (d1 > 0.001f || d2 > 0.001f || d3 > 0.001f) // can't be near coplaner!
{
neardot = dot;
t.raySect(m.mP1, m.mNormal, ref m.mNear1);
t.raySect(m.mP2, m.mNormal, ref m.mNear2);
t.raySect(m.mP3, m.mNormal, ref m.mNear3);
ret = true;
}
}
}
if (ret)
{
m.mC1 = m.mP1.Distance(m.mNear1);
m.mC2 = m.mP2.Distance(m.mNear2);
m.mC3 = m.mP3.Distance(m.mNear3);
m.mConcavity = m.mC1;
if (m.mC2 > m.mConcavity)
m.mConcavity = m.mC2;
if (m.mC3 > m.mConcavity)
m.mConcavity = m.mC3;
}
return ret;
}
private static float det(float3 p1, float3 p2, float3 p3)
{
return p1.x * p2.y * p3.z + p2.x * p3.y * p1.z + p3.x * p1.y * p2.z - p1.x * p3.y * p2.z - p2.x * p1.y * p3.z - p3.x * p2.y * p1.z;
}
public static float computeMeshVolume(List<float3> vertices, List<int> indices)
{
float volume = 0f;
for (int i = 0; i < indices.Count / 3; i++)
{
float3 p1 = vertices[indices[i * 3 + 0]];
float3 p2 = vertices[indices[i * 3 + 1]];
float3 p3 = vertices[indices[i * 3 + 2]];
volume += det(p1, p2, p3); // compute the volume of the tetrahedran relative to the origin.
}
volume *= (1.0f / 6.0f);
if (volume < 0f)
return -volume;
return volume;
}
public static float computeMeshVolume2(List<float3> vertices, List<int> indices)
{
float volume = 0f;
float3 p0 = vertices[0];
for (int i = 0; i < indices.Count / 3; i++)
{
float3 p1 = vertices[indices[i * 3 + 0]];
float3 p2 = vertices[indices[i * 3 + 1]];
float3 p3 = vertices[indices[i * 3 + 2]];
volume += tetVolume(p0, p1, p2, p3); // compute the volume of the tetrahedron relative to the root vertice
}
return volume * (1.0f / 6.0f);
}
private static float tetVolume(float3 p0, float3 p1, float3 p2, float3 p3)
{
float3 a = p1 - p0;
float3 b = p2 - p0;
float3 c = p3 - p0;
float3 cross = float3.cross(b, c);
float volume = float3.dot(a, cross);
if (volume < 0f)
return -volume;
return volume;
}
}
}