void SPHSystem::compDensPressure()
{
Particle *p;
Particle *np;
Vec2i cellPos;
Vec2i nearPos;
uint hash;
for(uint k=0; k<numParticle; k++)
{
p = &(particles[k]);
p->dens = 0.0f;
p->pres = 0.0f;
cellPos = calcCellPos(p->pos);
for(int i=-1; i<=1; i++)
{
for(int j=-1; j<=1; j++)
{
nearPos.x = cellPos.x + i;
nearPos.y = cellPos.y + j;
hash = calcCellHash(nearPos);
if(hash == 0xffffffff) continue;
np = cells[hash].head;
while(np != NULL)
{
Vec2f distVec = np->pos - p->pos;
float dist2 = distVec.LengthSquared();
if(dist2<INF || dist2>=kernel*kernel)
{
np = np->next;
continue;
}
p->dens = p->dens + mass * poly6(dist2);
np = np->next;
}
}
}
p->dens = p->dens + mass*poly6(0.0f);
p->pres = (pow(p->dens / restDensity, 7) - 1) * stiffness;
}
}
void comp(float * b, float const * a, int N) {
for (int i=0; i<N; ++i) {
b[i] = poly6(a[i]);
}
}
