55 lines
1.6 KiB
C++
55 lines
1.6 KiB
C++
|
|
#include "PositionBasedDynamics.h"
|
|
#include "CpuSoftClothDemoInternalData.h"
|
|
#include "ExplicitEuler.h"
|
|
|
|
void PositionBasedDynamics::solveLinks(struct CpuSoftClothDemoInternalData* clothData, char* vertexPositions, int vertexStride,float dt)
|
|
{
|
|
float kst = 1.f;
|
|
float kLST = 1.f;
|
|
|
|
|
|
for(int i=0; i<clothData->m_springs.size();i++)
|
|
{
|
|
|
|
ClothSpring& link=clothData->m_springs[i];
|
|
|
|
//if(l.m_c0>0)
|
|
{
|
|
|
|
float invMassA = clothData->m_particleMasses[link.m_particleIndexA]? 1.f/clothData->m_particleMasses[link.m_particleIndexA] : 0.f;
|
|
float invMassB = clothData->m_particleMasses[link.m_particleIndexB]? 1.f/clothData->m_particleMasses[link.m_particleIndexB] : 0.f;
|
|
|
|
float m_c0 = (invMassA+invMassB)*kLST;
|
|
float m_c1 = link.m_restLength*link.m_restLength;
|
|
|
|
b3Vector3& posA = (b3Vector3&)vertexPositions[link.m_particleIndexA*vertexStride];
|
|
b3Vector3& posB = (b3Vector3&)vertexPositions[link.m_particleIndexB*vertexStride];
|
|
|
|
const b3Vector3 del=posB-posA;
|
|
const float len=del.length2();
|
|
if (m_c1+len > B3_EPSILON)
|
|
{
|
|
const float k=((m_c1-len)/(m_c0*(m_c1+len)))*kst;
|
|
posA-=del*(k*invMassA);
|
|
posB+=del*(k*invMassB);
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
void PositionBasedDynamics::solveConstraints(struct CpuSoftClothDemoInternalData* clothData, char* vtx, int vertexStride,float dt)
|
|
{
|
|
B3_PROFILE("computeGravityForces");
|
|
ExplicitEuler::computeGravityForces(clothData,vtx,vertexStride,dt);
|
|
ExplicitEuler::integrateExplicitEuler(clothData,vtx,vertexStride,dt);
|
|
|
|
int numIter=10;
|
|
for (int i=0;i<numIter;i++)
|
|
{
|
|
solveLinks(clothData,vtx,vertexStride,dt);
|
|
}
|
|
|
|
};
|