149 lines
3.7 KiB
C++
149 lines
3.7 KiB
C++
/*
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
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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 "btMultiSphereShape.h"
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#include "BulletCollision/CollisionShapes/btCollisionMargin.h"
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#include "LinearMath/btQuaternion.h"
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btMultiSphereShape::btMultiSphereShape (const btVector3& inertiaHalfExtents,const btVector3* positions,const btScalar* radi,int numSpheres)
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:m_inertiaHalfExtents(inertiaHalfExtents)
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{
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btScalar startMargin = btScalar(1e30);
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m_numSpheres = numSpheres;
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for (int i=0;i<m_numSpheres;i++)
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{
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m_localPositions[i] = positions[i];
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m_radi[i] = radi[i];
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if (radi[i] < startMargin)
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startMargin = radi[i];
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}
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setMargin(startMargin);
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}
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btVector3 btMultiSphereShape::localGetSupportingVertexWithoutMargin(const btVector3& vec0)const
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{
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int i;
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btVector3 supVec(0,0,0);
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btScalar maxDot(btScalar(-1e30));
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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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} 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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btVector3 vtx;
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btScalar newDot;
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const btVector3* pos = &m_localPositions[0];
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const btScalar* rad = &m_radi[0];
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for (i=0;i<m_numSpheres;i++)
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{
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vtx = (*pos) +vec*m_localScaling*(*rad) - vec * getMargin();
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pos++;
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rad++;
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newDot = vec.dot(vtx);
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if (newDot > maxDot)
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{
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maxDot = newDot;
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supVec = vtx;
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}
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}
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return supVec;
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}
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void btMultiSphereShape::batchedUnitVectorGetSupportingVertexWithoutMargin(const btVector3* vectors,btVector3* supportVerticesOut,int numVectors) const
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{
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for (int j=0;j<numVectors;j++)
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{
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btScalar maxDot(btScalar(-1e30));
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const btVector3& vec = vectors[j];
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btVector3 vtx;
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btScalar newDot;
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const btVector3* pos = &m_localPositions[0];
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const btScalar* rad = &m_radi[0];
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for (int i=0;i<m_numSpheres;i++)
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{
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vtx = (*pos) +vec*m_localScaling*(*rad) - vec * getMargin();
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pos++;
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rad++;
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newDot = vec.dot(vtx);
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if (newDot > maxDot)
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{
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maxDot = newDot;
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supportVerticesOut[j] = vtx;
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}
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}
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}
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}
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void btMultiSphereShape::calculateLocalInertia(btScalar mass,btVector3& inertia)
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{
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//as an approximation, take the inertia of the box that bounds the spheres
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btTransform ident;
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ident.setIdentity();
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// btVector3 aabbMin,aabbMax;
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// getAabb(ident,aabbMin,aabbMax);
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btVector3 halfExtents = m_inertiaHalfExtents;//(aabbMax - aabbMin)* btScalar(0.5);
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btScalar margin = CONVEX_DISTANCE_MARGIN;
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btScalar lx=btScalar(2.)*(halfExtents[0]+margin);
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btScalar ly=btScalar(2.)*(halfExtents[1]+margin);
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btScalar lz=btScalar(2.)*(halfExtents[2]+margin);
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const btScalar x2 = lx*lx;
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const btScalar y2 = ly*ly;
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const btScalar z2 = lz*lz;
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const btScalar scaledmass = mass * btScalar(.08333333);
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inertia[0] = scaledmass * (y2+z2);
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inertia[1] = scaledmass * (x2+z2);
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inertia[2] = scaledmass * (x2+y2);
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}
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