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#ifndef B3_NEW_CONTACT_REDUCTION_H
#define B3_NEW_CONTACT_REDUCTION_H
#include "Bullet3Common/shared/b3Float4.h"
#include "Bullet3Collision/NarrowPhaseCollision/shared/b3RigidBodyData.h"
#include "Bullet3Collision/NarrowPhaseCollision/shared/b3Contact4Data.h"
#define GET_NPOINTS(x) (x).m_worldNormalOnB.w
int b3ExtractManifoldSequentialGlobal(__global const b3Float4* p, int nPoints, b3Float4ConstArg nearNormal, b3Int4* contactIdx)
{
if (nPoints == 0)
return 0;
if (nPoints <= 4)
return nPoints;
if (nPoints > 64)
nPoints = 64;
b3Float4 center = b3MakeFloat4(0, 0, 0, 0);
{
for (int i = 0; i < nPoints; i++)
center += p[i];
center /= (float)nPoints;
}
// sample 4 directions
b3Float4 aVector = p[0] - center;
b3Float4 u = b3Cross(nearNormal, aVector);
b3Float4 v = b3Cross(nearNormal, u);
u = b3Normalized(u);
v = b3Normalized(v);
//keep point with deepest penetration
float minW = FLT_MAX;
int minIndex = -1;
b3Float4 maxDots;
maxDots.x = FLT_MIN;
maxDots.y = FLT_MIN;
maxDots.z = FLT_MIN;
maxDots.w = FLT_MIN;
// idx, distance
for (int ie = 0; ie < nPoints; ie++)
{
if (p[ie].w < minW)
{
minW = p[ie].w;
minIndex = ie;
}
float f;
b3Float4 r = p[ie] - center;
f = b3Dot(u, r);
if (f < maxDots.x)
{
maxDots.x = f;
contactIdx[0].x = ie;
}
f = b3Dot(-u, r);
if (f < maxDots.y)
{
maxDots.y = f;
contactIdx[0].y = ie;
}
f = b3Dot(v, r);
if (f < maxDots.z)
{
maxDots.z = f;
contactIdx[0].z = ie;
}
f = b3Dot(-v, r);
if (f < maxDots.w)
{
maxDots.w = f;
contactIdx[0].w = ie;
}
}
if (contactIdx[0].x != minIndex && contactIdx[0].y != minIndex && contactIdx[0].z != minIndex && contactIdx[0].w != minIndex)
{
//replace the first contact with minimum (todo: replace contact with least penetration)
contactIdx[0].x = minIndex;
}
return 4;
}
__kernel void b3NewContactReductionKernel(__global b3Int4* pairs,
__global const b3RigidBodyData_t* rigidBodies,
__global const b3Float4* separatingNormals,
__global const int* hasSeparatingAxis,
__global struct b3Contact4Data* globalContactsOut,
__global b3Int4* clippingFaces,
__global b3Float4* worldVertsB2,
volatile __global int* nGlobalContactsOut,
int vertexFaceCapacity,
int contactCapacity,
int numPairs,
int pairIndex)
{
// int i = get_global_id(0);
//int pairIndex = i;
int i = pairIndex;
b3Int4 contactIdx;
contactIdx = b3MakeInt4(0, 1, 2, 3);
if (i < numPairs)
{
if (hasSeparatingAxis[i])
{
int nPoints = clippingFaces[pairIndex].w;
if (nPoints > 0)
{
__global b3Float4* pointsIn = &worldVertsB2[pairIndex * vertexFaceCapacity];
b3Float4 normal = -separatingNormals[i];
int nReducedContacts = b3ExtractManifoldSequentialGlobal(pointsIn, nPoints, normal, &contactIdx);
int dstIdx;
dstIdx = b3AtomicInc(nGlobalContactsOut);
//#if 0
b3Assert(dstIdx < contactCapacity);
if (dstIdx < contactCapacity)
{
__global struct b3Contact4Data* c = &globalContactsOut[dstIdx];
c->m_worldNormalOnB = -normal;
c->m_restituitionCoeffCmp = (0.f * 0xffff);
c->m_frictionCoeffCmp = (0.7f * 0xffff);
c->m_batchIdx = pairIndex;
int bodyA = pairs[pairIndex].x;
int bodyB = pairs[pairIndex].y;
pairs[pairIndex].w = dstIdx;
c->m_bodyAPtrAndSignBit = rigidBodies[bodyA].m_invMass == 0 ? -bodyA : bodyA;
c->m_bodyBPtrAndSignBit = rigidBodies[bodyB].m_invMass == 0 ? -bodyB : bodyB;
c->m_childIndexA = -1;
c->m_childIndexB = -1;
switch (nReducedContacts)
{
case 4:
c->m_worldPosB[3] = pointsIn[contactIdx.w];
case 3:
c->m_worldPosB[2] = pointsIn[contactIdx.z];
case 2:
c->m_worldPosB[1] = pointsIn[contactIdx.y];
case 1:
c->m_worldPosB[0] = pointsIn[contactIdx.x];
default:
{
}
};
GET_NPOINTS(*c) = nReducedContacts;
}
//#endif
} // if (numContactsOut>0)
} // if (hasSeparatingAxis[i])
} // if (i<numPairs)
}
#endif
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