241 lines
6.8 KiB
C++
241 lines
6.8 KiB
C++
/*
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Copyright (c) 2012 Advanced Micro Devices, Inc.
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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//Originally written by Erwin Coumans
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#include "btConvexUtility.h"
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#include "LinearMath/btConvexHullComputer.h"
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#include "LinearMath/btGrahamScan2dConvexHull.h"
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#include "LinearMath/btQuaternion.h"
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bool btConvexUtility::initializePolyhedralFeatures(const btAlignedObjectArray<btVector3>& orgVertices, bool mergeCoplanarTriangles)
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{
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btConvexHullComputer conv;
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conv.compute(&orgVertices[0].getX(), sizeof(btVector3),orgVertices.size(),0.f,0.f);
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btAlignedObjectArray<btVector3> faceNormals;
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int numFaces = conv.faces.size();
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faceNormals.resize(numFaces);
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btConvexHullComputer* convexUtil = &conv;
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btAlignedObjectArray<btFace> tmpFaces;
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tmpFaces.resize(numFaces);
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int numVertices = convexUtil->vertices.size();
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m_vertices.resize(numVertices);
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for (int p=0;p<numVertices;p++)
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{
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m_vertices[p] = convexUtil->vertices[p];
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}
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for (int i=0;i<numFaces;i++)
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{
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int face = convexUtil->faces[i];
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//printf("face=%d\n",face);
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const btConvexHullComputer::Edge* firstEdge = &convexUtil->edges[face];
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const btConvexHullComputer::Edge* edge = firstEdge;
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btVector3 edges[3];
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int numEdges = 0;
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//compute face normals
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btScalar maxCross2 = 0.f;
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int chosenEdge = -1;
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do
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{
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int src = edge->getSourceVertex();
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tmpFaces[i].m_indices.push_back(src);
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int targ = edge->getTargetVertex();
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btVector3 wa = convexUtil->vertices[src];
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btVector3 wb = convexUtil->vertices[targ];
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btVector3 newEdge = wb-wa;
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newEdge.normalize();
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if (numEdges<2)
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edges[numEdges++] = newEdge;
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edge = edge->getNextEdgeOfFace();
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} while (edge!=firstEdge);
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btScalar planeEq = 1e30f;
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if (numEdges==2)
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{
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faceNormals[i] = edges[0].cross(edges[1]);
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faceNormals[i].normalize();
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tmpFaces[i].m_plane[0] = faceNormals[i].getX();
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tmpFaces[i].m_plane[1] = faceNormals[i].getY();
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tmpFaces[i].m_plane[2] = faceNormals[i].getZ();
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tmpFaces[i].m_plane[3] = planeEq;
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}
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else
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{
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btAssert(0);//degenerate?
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faceNormals[i].setZero();
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}
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for (int v=0;v<tmpFaces[i].m_indices.size();v++)
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{
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btScalar eq = m_vertices[tmpFaces[i].m_indices[v]].dot(faceNormals[i]);
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if (planeEq>eq)
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{
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planeEq=eq;
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}
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}
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tmpFaces[i].m_plane[3] = -planeEq;
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}
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//merge coplanar faces
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btScalar faceWeldThreshold= 0.999f;
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btAlignedObjectArray<int> todoFaces;
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for (int i=0;i<tmpFaces.size();i++)
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todoFaces.push_back(i);
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while (todoFaces.size())
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{
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btAlignedObjectArray<int> coplanarFaceGroup;
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int refFace = todoFaces[todoFaces.size()-1];
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coplanarFaceGroup.push_back(refFace);
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btFace& faceA = tmpFaces[refFace];
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todoFaces.pop_back();
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btVector3 faceNormalA(faceA.m_plane[0],faceA.m_plane[1],faceA.m_plane[2]);
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for (int j=todoFaces.size()-1;j>=0;j--)
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{
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int i = todoFaces[j];
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btFace& faceB = tmpFaces[i];
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btVector3 faceNormalB(faceB.m_plane[0],faceB.m_plane[1],faceB.m_plane[2]);
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if (faceNormalA.dot(faceNormalB)>faceWeldThreshold)
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{
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coplanarFaceGroup.push_back(i);
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todoFaces.remove(i);
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}
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}
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bool did_merge = false;
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if (mergeCoplanarTriangles && coplanarFaceGroup.size()>1)
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{
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//do the merge: use Graham Scan 2d convex hull
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btAlignedObjectArray<GrahamVector2> orgpoints;
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for (int i=0;i<coplanarFaceGroup.size();i++)
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{
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btFace& face = tmpFaces[coplanarFaceGroup[i]];
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btVector3 faceNormal(face.m_plane[0],face.m_plane[1],face.m_plane[2]);
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btVector3 xyPlaneNormal(0,0,1);
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btQuaternion rotationArc = shortestArcQuat(faceNormal,xyPlaneNormal);
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for (int f=0;f<face.m_indices.size();f++)
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{
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int orgIndex = face.m_indices[f];
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btVector3 pt = m_vertices[orgIndex];
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btVector3 rotatedPt = quatRotate(rotationArc,pt);
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rotatedPt.setZ(0);
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bool found = false;
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for (int i=0;i<orgpoints.size();i++)
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{
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//if ((orgpoints[i].m_orgIndex == orgIndex) || ((rotatedPt-orgpoints[i]).length2()<0.0001))
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if (orgpoints[i].m_orgIndex == orgIndex)
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{
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found=true;
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break;
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}
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}
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if (!found)
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orgpoints.push_back(GrahamVector2(rotatedPt,orgIndex));
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}
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}
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btFace combinedFace;
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for (int i=0;i<4;i++)
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combinedFace.m_plane[i] = tmpFaces[coplanarFaceGroup[0]].m_plane[i];
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btAlignedObjectArray<GrahamVector2> hull;
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GrahamScanConvexHull2D(orgpoints,hull);
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for (int i=0;i<hull.size();i++)
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{
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combinedFace.m_indices.push_back(hull[i].m_orgIndex);
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for(int k = 0; k < orgpoints.size(); k++) {
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if(orgpoints[k].m_orgIndex == hull[i].m_orgIndex) {
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orgpoints[k].m_orgIndex = -1; // invalidate...
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break;
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}
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}
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}
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// are there rejected vertices?
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bool reject_merge = false;
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for(int i = 0; i < orgpoints.size(); i++) {
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if(orgpoints[i].m_orgIndex == -1)
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continue; // this is in the hull...
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// this vertex is rejected -- is anybody else using this vertex?
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for(int j = 0; j < tmpFaces.size(); j++) {
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btFace& face = tmpFaces[j];
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// is this a face of the current coplanar group?
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bool is_in_current_group = false;
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for(int k = 0; k < coplanarFaceGroup.size(); k++) {
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if(coplanarFaceGroup[k] == j) {
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is_in_current_group = true;
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break;
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}
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}
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if(is_in_current_group) // ignore this face...
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continue;
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// does this face use this rejected vertex?
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for(int v = 0; v < face.m_indices.size(); v++) {
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if(face.m_indices[v] == orgpoints[i].m_orgIndex) {
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// this rejected vertex is used in another face -- reject merge
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reject_merge = true;
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break;
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}
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}
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if(reject_merge)
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break;
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}
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if(reject_merge)
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break;
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}
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if(!reject_merge) {
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// do this merge!
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did_merge = true;
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m_faces.push_back(combinedFace);
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}
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}
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if(!did_merge)
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{
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for (int i=0;i<coplanarFaceGroup.size();i++)
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{
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m_faces.push_back(tmpFaces[coplanarFaceGroup[i]]);
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}
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}
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}
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return true;
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}
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