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/*
* Copyright (c) 2005 Erwin Coumans http://continuousphysics.com/Bullet/
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies.
* Erwin Coumans makes no representations about the suitability
* of this software for any purpose.
* It is provided "as is" without express or implied warranty.
*/
#include "MultiSphereShape.h"
#include "NarrowPhaseCollision/CollisionMargin.h"
#include "SimdQuaternion.h"
MultiSphereShape::MultiSphereShape (const SimdVector3& inertiaHalfExtents,const SimdVector3* positions,const SimdScalar* radi,int numSpheres)
:m_inertiaHalfExtents(inertiaHalfExtents)
{
m_minRadius = 1e30f;
m_numSpheres = numSpheres;
for (int i=0;i<m_numSpheres;i++)
{
m_localPositions[i] = positions[i];
m_radi[i] = radi[i];
if (radi[i] < m_minRadius)
m_minRadius = radi[i];
}
SetMargin(m_minRadius);
}
SimdVector3 MultiSphereShape::LocalGetSupportingVertexWithoutMargin(const SimdVector3& vec0)const
{
int i;
SimdVector3 supVec(0,0,0);
SimdScalar maxDot(-1e30f);
SimdVector3 vec = vec0;
SimdScalar lenSqr = vec.length2();
if (lenSqr < 0.0001f)
{
vec.setValue(1,0,0);
} else
{
float rlen = 1.f / SimdSqrt(lenSqr );
vec *= rlen;
}
SimdVector3 vtx;
SimdScalar newDot;
const SimdVector3* pos = &m_localPositions[0];
const SimdScalar* rad = &m_radi[0];
for (i=0;i<m_numSpheres;i++)
{
vtx = (*pos) +vec*((*rad)-m_minRadius);
pos++;
rad++;
newDot = vec.dot(vtx);
if (newDot > maxDot)
{
maxDot = newDot;
supVec = vtx;
}
}
return supVec;
}
void MultiSphereShape::CalculateLocalInertia(SimdScalar mass,SimdVector3& inertia)
{
//as an approximation, take the inertia of the box that bounds the spheres
SimdTransform ident;
ident.setIdentity();
// SimdVector3 aabbMin,aabbMax;
// GetAabb(ident,aabbMin,aabbMax);
SimdVector3 halfExtents = m_inertiaHalfExtents;//(aabbMax - aabbMin)* 0.5f;
float margin = CONVEX_DISTANCE_MARGIN;
SimdScalar lx=2.f*(halfExtents[0]+margin);
SimdScalar ly=2.f*(halfExtents[1]+margin);
SimdScalar lz=2.f*(halfExtents[2]+margin);
const SimdScalar x2 = lx*lx;
const SimdScalar y2 = ly*ly;
const SimdScalar z2 = lz*lz;
const SimdScalar scaledmass = mass * 0.08333333f;
inertia[0] = scaledmass * (y2+z2);
inertia[1] = scaledmass * (x2+z2);
inertia[2] = scaledmass * (x2+y2);
}
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