void SPHSystem::compNearForce(Particle& p,Vec2i cellPos){
Vec2i nearPos;
for(int m = -1; m <= 1; m++)
for(int n = -1; n <= 1; n++){
nearPos.x = cellPos.x + n;
nearPos.y = cellPos.y + m;
if(nearPos.x<0||nearPos.x>=gridSize.x||nearPos.y<0||nearPos.y>=gridSize.y)
continue;
list<Particle>& np = *cells[nearPos.x][nearPos.y].pList;
if(!np.empty()){
for (list<Particle>::iterator it = np.begin(); it != np.end(); it++){
Vec2f distVec = p.pos - it->pos;
float dist2 = distVec.LengthSquared();
if(dist2 < kernel_radius*kernel_radius && dist2 > INF){
float dist = sqrt(dist2);
float V = mass / it->dens;
float tempForce = V * (p.pres + it->pres) * spiky(dist);
p.acc = p.acc - distVec*tempForce/dist;
Vec2f relVel;
relVel = it->ev-p.ev;
tempForce = V * viscosity * visco(dist);
p.acc = p.acc + relVel*tempForce;
}
}
}
}
}
void SPHSystem::compNearDensPressure(Particle& p, Vec2i cellPos){
Vec2i nearPos;
p.dens = 0.0f;
p.pres = 0.0f;
for(int m = -1; m <= 1; m++)
for(int n = -1; n <= 1; n++){
nearPos.x = cellPos.x + m;
nearPos.y = cellPos.y + n;
if(nearPos.x<0||nearPos.x>=gridSize.x||nearPos.y<0||nearPos.y>=gridSize.y)
continue;
list<Particle>& np = *cells[nearPos.x][nearPos.y].pList;
if(np.empty())
continue;
for (list<Particle>::iterator it = np.begin(); it != np.end(); it++){
Vec2f distVec = it->pos - p.pos;
float dist = distVec.LengthSquared();
//—омнительный код
if(dist>=kernel_radius*kernel_radius)
continue;
p.dens = p.dens + mass * poly6(dist);
}
}
p.pres = (pow(p.dens / restDensity, 7) - 1) * stiffness;
}
void SPHSystem::compForce()
{
Particle *p;
Particle *np;
Vec2i cellPos;
Vec2i nearPos;
uint hash;
for(uint k=0; k<numParticle; k++)
{
p = &(particles[k]);
p->acc = Vec2f(0.0f, 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 = p->pos - np->pos;
float dist2 = distVec.LengthSquared();
if(dist2 < kernel*kernel && dist2 > INF)
{
float dist = sqrt(dist2);
float V = mass / p->dens;
float tempForce = V * (p->pres+np->pres) * spiky(dist);
p->acc = p->acc - distVec*tempForce/dist;
Vec2f relVel;
relVel = np->ev-p->ev;
tempForce = V * viscosity * visco(dist);
p->acc = p->acc + relVel*tempForce;
}
np = np->next;
}
}
}
p->acc = p->acc/p->dens+gravity;
}
}
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;
}
}
