284 lines
7.8 KiB
C++
284 lines
7.8 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2009 Erwin Coumans http://bulletphysics.org
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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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#include "btConvexTriangleMeshShape.h"
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#include "BulletCollision/CollisionShapes/btCollisionMargin.h"
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#include "LinearMath/btQuaternion.h"
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#include "BulletCollision/CollisionShapes/btStridingMeshInterface.h"
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btConvexTriangleMeshShape ::btConvexTriangleMeshShape(btStridingMeshInterface* meshInterface, bool calcAabb)
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: btPolyhedralConvexAabbCachingShape(), m_stridingMesh(meshInterface)
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{
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m_shapeType = CONVEX_TRIANGLEMESH_SHAPE_PROXYTYPE;
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if (calcAabb)
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recalcLocalAabb();
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}
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///It's not nice to have all this virtual function overhead, so perhaps we can also gather the points once
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///but then we are duplicating
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class LocalSupportVertexCallback : public btInternalTriangleIndexCallback
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{
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btVector3 m_supportVertexLocal;
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public:
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btScalar m_maxDot;
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btVector3 m_supportVecLocal;
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LocalSupportVertexCallback(const btVector3& supportVecLocal)
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: m_supportVertexLocal(btScalar(0.), btScalar(0.), btScalar(0.)),
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m_maxDot(btScalar(-BT_LARGE_FLOAT)),
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m_supportVecLocal(supportVecLocal)
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{
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}
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virtual void internalProcessTriangleIndex(btVector3* triangle, int partId, int triangleIndex)
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{
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(void)triangleIndex;
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(void)partId;
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for (int i = 0; i < 3; i++)
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{
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btScalar dot = m_supportVecLocal.dot(triangle[i]);
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if (dot > m_maxDot)
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{
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m_maxDot = dot;
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m_supportVertexLocal = triangle[i];
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}
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}
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}
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btVector3 GetSupportVertexLocal()
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{
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return m_supportVertexLocal;
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}
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};
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btVector3 btConvexTriangleMeshShape::localGetSupportingVertexWithoutMargin(const btVector3& vec0) const
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{
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btVector3 supVec(btScalar(0.), btScalar(0.), btScalar(0.));
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btVector3 vec = vec0;
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btScalar lenSqr = vec.length2();
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if (lenSqr < btScalar(0.0001))
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{
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vec.setValue(1, 0, 0);
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}
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else
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{
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btScalar rlen = btScalar(1.) / btSqrt(lenSqr);
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vec *= rlen;
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}
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LocalSupportVertexCallback supportCallback(vec);
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btVector3 aabbMax(btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT));
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m_stridingMesh->InternalProcessAllTriangles(&supportCallback, -aabbMax, aabbMax);
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supVec = supportCallback.GetSupportVertexLocal();
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return supVec;
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}
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void btConvexTriangleMeshShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors, btVector3* supportVerticesOut, int numVectors) const
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{
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//use 'w' component of supportVerticesOut?
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{
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for (int i = 0; i < numVectors; i++)
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{
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supportVerticesOut[i][3] = btScalar(-BT_LARGE_FLOAT);
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}
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}
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///@todo: could do the batch inside the callback!
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for (int j = 0; j < numVectors; j++)
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{
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const btVector3& vec = vectors[j];
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LocalSupportVertexCallback supportCallback(vec);
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btVector3 aabbMax(btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT));
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m_stridingMesh->InternalProcessAllTriangles(&supportCallback, -aabbMax, aabbMax);
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supportVerticesOut[j] = supportCallback.GetSupportVertexLocal();
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}
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}
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btVector3 btConvexTriangleMeshShape::localGetSupportingVertex(const btVector3& vec) const
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{
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btVector3 supVertex = localGetSupportingVertexWithoutMargin(vec);
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if (getMargin() != btScalar(0.))
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{
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btVector3 vecnorm = vec;
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if (vecnorm.length2() < (SIMD_EPSILON * SIMD_EPSILON))
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{
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vecnorm.setValue(btScalar(-1.), btScalar(-1.), btScalar(-1.));
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}
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vecnorm.normalize();
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supVertex += getMargin() * vecnorm;
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}
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return supVertex;
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}
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//currently just for debugging (drawing), perhaps future support for algebraic continuous collision detection
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//Please note that you can debug-draw btConvexTriangleMeshShape with the Raytracer Demo
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int btConvexTriangleMeshShape::getNumVertices() const
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{
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//cache this?
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return 0;
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}
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int btConvexTriangleMeshShape::getNumEdges() const
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{
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return 0;
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}
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void btConvexTriangleMeshShape::getEdge(int, btVector3&, btVector3&) const
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{
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btAssert(0);
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}
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void btConvexTriangleMeshShape::getVertex(int, btVector3&) const
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{
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btAssert(0);
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}
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int btConvexTriangleMeshShape::getNumPlanes() const
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{
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return 0;
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}
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void btConvexTriangleMeshShape::getPlane(btVector3&, btVector3&, int) const
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{
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btAssert(0);
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}
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//not yet
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bool btConvexTriangleMeshShape::isInside(const btVector3&, btScalar) const
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{
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btAssert(0);
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return false;
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}
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void btConvexTriangleMeshShape::setLocalScaling(const btVector3& scaling)
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{
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m_stridingMesh->setScaling(scaling);
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recalcLocalAabb();
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}
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const btVector3& btConvexTriangleMeshShape::getLocalScaling() const
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{
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return m_stridingMesh->getScaling();
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}
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void btConvexTriangleMeshShape::calculatePrincipalAxisTransform(btTransform& principal, btVector3& inertia, btScalar& volume) const
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{
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class CenterCallback : public btInternalTriangleIndexCallback
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{
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bool first;
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btVector3 ref;
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btVector3 sum;
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btScalar volume;
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public:
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CenterCallback() : first(true), ref(0, 0, 0), sum(0, 0, 0), volume(0)
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{
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}
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virtual void internalProcessTriangleIndex(btVector3* triangle, int partId, int triangleIndex)
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{
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(void)triangleIndex;
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(void)partId;
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if (first)
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{
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ref = triangle[0];
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first = false;
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}
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else
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{
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btScalar vol = btFabs((triangle[0] - ref).triple(triangle[1] - ref, triangle[2] - ref));
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sum += (btScalar(0.25) * vol) * ((triangle[0] + triangle[1] + triangle[2] + ref));
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volume += vol;
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}
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}
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btVector3 getCenter()
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{
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return (volume > 0) ? sum / volume : ref;
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}
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btScalar getVolume()
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{
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return volume * btScalar(1. / 6);
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}
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};
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class InertiaCallback : public btInternalTriangleIndexCallback
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{
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btMatrix3x3 sum;
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btVector3 center;
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public:
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InertiaCallback(btVector3& center) : sum(0, 0, 0, 0, 0, 0, 0, 0, 0), center(center)
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{
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}
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virtual void internalProcessTriangleIndex(btVector3* triangle, int partId, int triangleIndex)
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{
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(void)triangleIndex;
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(void)partId;
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btMatrix3x3 i;
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btVector3 a = triangle[0] - center;
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btVector3 b = triangle[1] - center;
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btVector3 c = triangle[2] - center;
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btScalar volNeg = -btFabs(a.triple(b, c)) * btScalar(1. / 6);
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for (int j = 0; j < 3; j++)
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{
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for (int k = 0; k <= j; k++)
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{
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i[j][k] = i[k][j] = volNeg * (btScalar(0.1) * (a[j] * a[k] + b[j] * b[k] + c[j] * c[k]) + btScalar(0.05) * (a[j] * b[k] + a[k] * b[j] + a[j] * c[k] + a[k] * c[j] + b[j] * c[k] + b[k] * c[j]));
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}
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}
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btScalar i00 = -i[0][0];
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btScalar i11 = -i[1][1];
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btScalar i22 = -i[2][2];
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i[0][0] = i11 + i22;
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i[1][1] = i22 + i00;
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i[2][2] = i00 + i11;
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sum[0] += i[0];
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sum[1] += i[1];
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sum[2] += i[2];
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}
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btMatrix3x3& getInertia()
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{
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return sum;
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}
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};
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CenterCallback centerCallback;
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btVector3 aabbMax(btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT), btScalar(BT_LARGE_FLOAT));
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m_stridingMesh->InternalProcessAllTriangles(¢erCallback, -aabbMax, aabbMax);
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btVector3 center = centerCallback.getCenter();
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principal.setOrigin(center);
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volume = centerCallback.getVolume();
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InertiaCallback inertiaCallback(center);
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m_stridingMesh->InternalProcessAllTriangles(&inertiaCallback, -aabbMax, aabbMax);
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btMatrix3x3& i = inertiaCallback.getInertia();
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i.diagonalize(principal.getBasis(), btScalar(0.00001), 20);
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inertia.setValue(i[0][0], i[1][1], i[2][2]);
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inertia /= volume;
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}
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