private void AddCollisionForce()
{
_points.Clear();
_nodes.Clear();
for (int i = 0; i < cells.Count; i++)
{
var p = cells[i];
_points.Add(new double[] { p.position.x, p.position.y, p.position.z });
_nodes.Add(i);
}
KDTree <double, int> tree = new KDTree <double, int>(3, _points.ToArray(), _nodes.ToArray(), L2Norm);
double radiusSquared = parameters.radius * parameters.radius;
for (int i = 0; i < cells.Count; i++)
{
GParticle p = cells[i];
p.collisions = 0;
var rsquared = parameters.radius * parameters.radius;
Tuple <double[], int>[] neighbors = tree.NearestNeighbors(new double[] { p.position.x, p.position.y, p.position.z }, (int)parameters.maxNeighbors);
foreach (var neighbor in neighbors)
{
GParticle q = cells[neighbor.Item2];
Vector3 displacement = p.position - q.position;
float distanceSquared = displacement.x * displacement.x +
displacement.y * displacement.y +
displacement.z * displacement.z;
if ((i != neighbor.Item2) && (!p.connectedTo(neighbor.Item2)))
{
displacement.Normalize();
displacement *= (rsquared - distanceSquared) / rsquared; // TODO sqrt here? NGS what is this even ????
p.delta += displacement * parameters.collisionFactor;
p.collisions++;
}
}
}
}
private void AddCollisionBruteForce()
{
var tree = new KdTree <float, int>(3, new FloatMath());
for (int i = 0; i < cells.Count; i++)
{
tree.Add(new[] { cells[i].position.x, cells[i].position.y, cells[i].position.z }, i);
}
double radiusSquared = parameters.radius * parameters.radius;
for (int i = 0; i < cells.Count; i++)
{
GParticle p = cells[i];
p.collisions = 0;
var rsquared = parameters.radius * parameters.radius;
var neighbors = tree.GetNearestNeighbours(new[] { cells[i].position.x, cells[i].position.y, cells[i].position.z },
(int)parameters.maxNeighbors);
for (int j = 0; j < neighbors.Length; j++)
{
GParticle q = cells[neighbors[j].Value];
Vector3 displacement = p.position - q.position;
if (displacement.magnitude < parameters.radius)
{
float distanceSquared = displacement.x * displacement.x +
displacement.y * displacement.y +
displacement.z * displacement.z;
if ((i != j) && (!p.connectedTo(j)))
{
displacement.Normalize();
displacement *= (rsquared - distanceSquared) / rsquared; // TODO sqrt here? NGS what is this even ????
p.delta += displacement * parameters.collisionFactor;
p.collisions++;
}
}
}
}
}
