static R3Vector calculate_sink_force(R3Scene* scene, R3Particle* particle)
{
R3ParticleSink* sink;
R3Vector force = R3Vector(0,0,0);
for (int i = 0; i < scene->NParticleSinks(); i++)
{
sink = scene->ParticleSink(i);
if (sink->shape->type == R3_SPHERE_SHAPE)
{
R3Sphere* sphere = sink->shape->sphere;
R3Point center = sphere->Center();
R3Vector f = -(particle->position - center);
double d = f.Length() - sphere->Radius();
f.Normalize();
double mag = sink->intensity / (sink->constant_attenuation +
sink->linear_attenuation*d +
sink->quadratic_attenuation*d*d);
force += f*mag;
}
else if (sink->shape->type == R3_MESH_SHAPE)
{
R3Mesh* mesh = sink->shape->mesh;
R3Point center = mesh->Center();
R3Vector f = -(particle->position - center);
double d = f.Length();
f.Normalize();
double mag = sink->intensity / (sink->constant_attenuation +
sink->linear_attenuation*d +
sink->quadratic_attenuation*d*d);
force += f*mag;
}
else if (sink->shape->type == R3_BOX_SHAPE)
{
R3Box* box = sink->shape->box;
R3Point center = R3Point((box->XMax() - box->XMin())/2 + box->XMin(),
(box->YMax() - box->YMin())/2 + box->YMin(),
(box->ZMax() - box->ZMin())/2 + box->ZMin());
R3Vector f = -(particle->position - center);
double d = f.Length();
f.Normalize();
double mag = sink->intensity / (sink->constant_attenuation +
sink->linear_attenuation*d +
sink->quadratic_attenuation*d*d);
force += f*mag;
}
}
return force;
}
