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Add an improved way to approximate the area of the contact manifold, using 4 points instead of 3. It is switched off by default (need to check performance first), use gContactCalcArea3Points = false to enable it. Thanks to Hiroshi Matsuike for the improvement!

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Use App prefix for AppHfFluidDemo
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erwin.coumans
2012-03-01 05:02:01 +00:00
parent 99db5e6c8a
commit 0daf69afb6
2 changed files with 49 additions and 7 deletions
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54
src/BulletCollision/NarrowPhaseCollision/btPersistentManifold.cpp
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@@ -1,4 +1,4 @@
/*
/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans http://continuousphysics.com/Bullet/
@@ -21,7 +21,9 @@ subject to the following restrictions:
btScalar gContactBreakingThreshold = btScalar(0.02);
ContactDestroyedCallback gContactDestroyedCallback = 0;
ContactProcessedCallback gContactProcessedCallback = 0;
///gContactCalcArea3Points will approximate the convex hull area using 3 points
///when setting it to false, it will use 4 points to compute the area: it is more accurate but slower
bool gContactCalcArea3Points = true;
btPersistentManifold::btPersistentManifold()
@@ -84,10 +86,28 @@ void btPersistentManifold::clearUserCache(btManifoldPoint& pt)
}
static inline btScalar calcArea4Points(const btVector3 &p0,const btVector3 &p1,const btVector3 &p2,const btVector3 &p3)
{
// It calculates possible 3 area constructed from random 4 points and returns the biggest one.
btVector3 a[3],b[3];
a[0] = p0 - p1;
a[1] = p0 - p2;
a[2] = p0 - p3;
b[0] = p2 - p3;
b[1] = p1 - p3;
b[2] = p1 - p2;
//todo: Following 3 cross production can be easily optimized by SIMD.
btVector3 tmp0 = a[0].cross(b[0]);
btVector3 tmp1 = a[1].cross(b[1]);
btVector3 tmp2 = a[2].cross(b[2]);
return btMax(btMax(tmp0.length2(),tmp1.length2()),tmp2.length2());
}
int btPersistentManifold::sortCachedPoints(const btManifoldPoint& pt)
{
//calculate 4 possible cases areas, and take biggest area
//also need to keep 'deepest'
@@ -106,6 +126,9 @@ int btPersistentManifold::sortCachedPoints(const btManifoldPoint& pt)
#endif //KEEP_DEEPEST_POINT
btScalar res0(btScalar(0.)),res1(btScalar(0.)),res2(btScalar(0.)),res3(btScalar(0.));
if (gContactCalcArea3Points)
{
if (maxPenetrationIndex != 0)
{
btVector3 a0 = pt.m_localPointA-m_pointCache[1].m_localPointA;
@@ -136,10 +159,29 @@ int btPersistentManifold::sortCachedPoints(const btManifoldPoint& pt)
btVector3 cross = a3.cross(b3);
res3 = cross.length2();
}
}
else
{
if(maxPenetrationIndex != 0) {
res0 = calcArea4Points(pt.m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[2].m_localPointA,m_pointCache[3].m_localPointA);
}
btVector4 maxvec(res0,res1,res2,res3);
int biggestarea = maxvec.closestAxis4();
return biggestarea;
if(maxPenetrationIndex != 1) {
res1 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[2].m_localPointA,m_pointCache[3].m_localPointA);
}
if(maxPenetrationIndex != 2) {
res2 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[3].m_localPointA);
}
if(maxPenetrationIndex != 3) {
res3 = calcArea4Points(pt.m_localPointA,m_pointCache[0].m_localPointA,m_pointCache[1].m_localPointA,m_pointCache[2].m_localPointA);
}
}
btVector4 maxvec(res0,res1,res2,res3);
int biggestarea = maxvec.closestAxis4();
return biggestarea;
}