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