242 lines
7.3 KiB
C++
242 lines
7.3 KiB
C++
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/*
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Stan Melax Convex Hull Computation
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Copyright (c) 2008 Stan Melax http://www.melax.com/
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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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///includes modifications/improvements by John Ratcliff, see BringOutYourDead below.
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#ifndef BT_CD_HULL_H
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#define BT_CD_HULL_H
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#include "btVector3.h"
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#include "btAlignedObjectArray.h"
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typedef btAlignedObjectArray<unsigned int> TUIntArray;
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class HullResult
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{
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public:
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HullResult(void)
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{
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mPolygons = true;
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mNumOutputVertices = 0;
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mNumFaces = 0;
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mNumIndices = 0;
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}
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bool mPolygons; // true if indices represents polygons, false indices are triangles
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unsigned int mNumOutputVertices; // number of vertices in the output hull
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btAlignedObjectArray<btVector3> m_OutputVertices; // array of vertices
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unsigned int mNumFaces; // the number of faces produced
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unsigned int mNumIndices; // the total number of indices
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btAlignedObjectArray<unsigned int> m_Indices; // pointer to indices.
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// If triangles, then indices are array indexes into the vertex list.
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// If polygons, indices are in the form (number of points in face) (p1, p2, p3, ..) etc..
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};
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enum HullFlag
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{
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QF_TRIANGLES = (1<<0), // report results as triangles, not polygons.
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QF_REVERSE_ORDER = (1<<1), // reverse order of the triangle indices.
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QF_DEFAULT = QF_TRIANGLES
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};
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class HullDesc
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{
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public:
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HullDesc(void)
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{
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mFlags = QF_DEFAULT;
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mVcount = 0;
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mVertices = 0;
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mVertexStride = sizeof(btVector3);
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mNormalEpsilon = 0.001f;
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mMaxVertices = 4096; // maximum number of points to be considered for a convex hull.
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mMaxFaces = 4096;
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};
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HullDesc(HullFlag flag,
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unsigned int vcount,
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const btVector3 *vertices,
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unsigned int stride = sizeof(btVector3))
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{
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mFlags = flag;
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mVcount = vcount;
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mVertices = vertices;
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mVertexStride = stride;
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mNormalEpsilon = btScalar(0.001);
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mMaxVertices = 4096;
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}
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bool HasHullFlag(HullFlag flag) const
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{
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if ( mFlags & flag ) return true;
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return false;
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}
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void SetHullFlag(HullFlag flag)
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{
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mFlags|=flag;
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}
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void ClearHullFlag(HullFlag flag)
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{
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mFlags&=~flag;
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}
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unsigned int mFlags; // flags to use when generating the convex hull.
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unsigned int mVcount; // number of vertices in the input point cloud
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const btVector3 *mVertices; // the array of vertices.
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unsigned int mVertexStride; // the stride of each vertex, in bytes.
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btScalar mNormalEpsilon; // the epsilon for removing duplicates. This is a normalized value, if normalized bit is on.
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unsigned int mMaxVertices; // maximum number of vertices to be considered for the hull!
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unsigned int mMaxFaces;
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};
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enum HullError
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{
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QE_OK, // success!
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QE_FAIL // failed.
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};
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class btPlane
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{
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public:
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btVector3 normal;
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btScalar dist; // distance below origin - the D from plane equasion Ax+By+Cz+D=0
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btPlane(const btVector3 &n,btScalar d):normal(n),dist(d){}
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btPlane():normal(),dist(0){}
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};
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class ConvexH
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{
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public:
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class HalfEdge
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{
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public:
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short ea; // the other half of the edge (index into edges list)
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unsigned char v; // the vertex at the start of this edge (index into vertices list)
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unsigned char p; // the facet on which this edge lies (index into facets list)
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HalfEdge(){}
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HalfEdge(short _ea,unsigned char _v, unsigned char _p):ea(_ea),v(_v),p(_p){}
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};
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ConvexH()
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{
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}
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~ConvexH()
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{
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}
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btAlignedObjectArray<btVector3> vertices;
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btAlignedObjectArray<HalfEdge> edges;
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btAlignedObjectArray<btPlane> facets;
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ConvexH(int vertices_size,int edges_size,int facets_size);
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};
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class int4
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{
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public:
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int x,y,z,w;
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int4(){};
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int4(int _x,int _y, int _z,int _w){x=_x;y=_y;z=_z;w=_w;}
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const int& operator[](int i) const {return (&x)[i];}
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int& operator[](int i) {return (&x)[i];}
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};
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class PHullResult
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{
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public:
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PHullResult(void)
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{
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mVcount = 0;
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mIndexCount = 0;
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mFaceCount = 0;
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mVertices = 0;
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}
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unsigned int mVcount;
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unsigned int mIndexCount;
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unsigned int mFaceCount;
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btVector3* mVertices;
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TUIntArray m_Indices;
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};
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///The HullLibrary class can create a convex hull from a collection of vertices, using the ComputeHull method.
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///The btShapeHull class uses this HullLibrary to create a approximate convex mesh given a general (non-polyhedral) convex shape.
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class HullLibrary
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{
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btAlignedObjectArray<class btHullTriangle*> m_tris;
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public:
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btAlignedObjectArray<int> m_vertexIndexMapping;
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HullError CreateConvexHull(const HullDesc& desc, // describes the input request
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HullResult& result); // contains the resulst
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HullError ReleaseResult(HullResult &result); // release memory allocated for this result, we are done with it.
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private:
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bool ComputeHull(unsigned int vcount,const btVector3 *vertices,PHullResult &result,unsigned int vlimit);
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class btHullTriangle* allocateTriangle(int a,int b,int c);
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void deAllocateTriangle(btHullTriangle*);
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void b2bfix(btHullTriangle* s,btHullTriangle*t);
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void removeb2b(btHullTriangle* s,btHullTriangle*t);
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void checkit(btHullTriangle *t);
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btHullTriangle* extrudable(btScalar epsilon);
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int calchull(btVector3 *verts,int verts_count, TUIntArray& tris_out, int &tris_count,int vlimit);
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int calchullgen(btVector3 *verts,int verts_count, int vlimit);
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int4 FindSimplex(btVector3 *verts,int verts_count,btAlignedObjectArray<int> &allow);
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class ConvexH* ConvexHCrop(ConvexH& convex,const btPlane& slice);
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void extrude(class btHullTriangle* t0,int v);
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ConvexH* test_cube();
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//BringOutYourDead (John Ratcliff): When you create a convex hull you hand it a large input set of vertices forming a 'point cloud'.
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//After the hull is generated it give you back a set of polygon faces which index the *original* point cloud.
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//The thing is, often times, there are many 'dead vertices' in the point cloud that are on longer referenced by the hull.
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//The routine 'BringOutYourDead' find only the referenced vertices, copies them to an new buffer, and re-indexes the hull so that it is a minimal representation.
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void BringOutYourDead(const btVector3* verts,unsigned int vcount, btVector3* overts,unsigned int &ocount,unsigned int* indices,unsigned indexcount);
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bool CleanupVertices(unsigned int svcount,
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const btVector3* svertices,
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unsigned int stride,
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unsigned int &vcount, // output number of vertices
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btVector3* vertices, // location to store the results.
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btScalar normalepsilon,
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btVector3& scale);
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};
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#endif //BT_CD_HULL_H
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