static void applyForces(struct particle_system *ps, struct particle *p)
{
int i = 0;
vec3 force;
vec3 dir;
float m, d, s;
vec3Copy(p->dir, p->acc);
do {
switch(ps->forces[i].type) {
case PARTICLE_FORCE_DIRECTIONAL:
vec3Copy(ps->forces[i].dir, force);
break;
case PARTICLE_FORCE_FLUID:
s = vec3Mag(p->acc);
vec3Copy(p->acc, force);
vec3Normalize(force, force);
vec3Mul(force, -ps->forces[i].value*s*s, force);
break;
case PARTICLE_FORCE_ATTRACTION:
vec3Sub(ps->forces[i].loc, p->loc, dir);
d = vec3Mag(dir);
vec3Normalize(dir, dir);
m = 0.00001*ps->forces[i].value*p->mass / (d*d);
vec3Mul(dir, m, force);
break;
}
vec3Add(p->acc, force, p->acc);
} while(++i < ps->nbforces);
vec3Div(p->acc, p->mass, p->acc);
vec3Add(p->vel, p->acc, p->vel);
vec3Add(p->loc, p->vel, p->loc);
}
void spherify(Solid* s) {
unsigned n = s->nVerts;
Vec3 centroid = { 0,0,0 };
unsigned i;
for(i=0;i<n;++i) {
vec3Add(centroid,centroid,s->verts[i].loc);
}
vec3Mult(centroid,centroid,1.0/n);
Vec3* diffs = malloc(n*sizeof(Vec3));
float* dists = malloc(n*sizeof(float));
float maxR = 0;
for(i=0;i<n;++i) {
vec3Sub(diffs[i],s->verts[i].loc,centroid);
float r = vec3Mag(diffs[i]);
dists[i] = r;
if(r > maxR) {
maxR = r;
}
}
for(i=0;i<n;++i) {
vec3Mult(diffs[i],diffs[i],1.0/dists[i]);
vec3Copy(s->verts[i].normal,diffs[i]);
vec3Mult(diffs[i],diffs[i],maxR);
vec3Add(s->verts[i].loc,centroid,diffs[i]);
}
free(dists);
free(diffs);
}
