/*
* /// <summary>
* ///
* /// </summary>
* /// <param name="weight"></param>
* private void LaplacianFair(double weight)
* {
* for (int i = 0; i < _verts.Count; i++)
* {
* var v0 = _verts[i];
* if (v0.IsRemoved) continue;
*
* // calculate graph laplacian
* var sum = new Vec3d();
* var count = 0;
*
* foreach (var v1 in v0.ConnectedVertices)
* {
* sum += v1.Position;
* count++;
* }
*
* double t = 1.0 / count;
* var move = sum * t - v0.Position;
*
* // apply to central vertex
* v0.MoveSum += move * weight;
* v0.WeightSum += weight;
*
* // distribute negated to neighbours
* move *= -t;
* foreach (var v1 in v0.ConnectedVertices)
* {
* v1.MoveSum += move * weight;
* v1.WeightSum += weight;
* }
* }
* }
*/
/// <summary>
/// Note this method assumes that vertex deltas and weights are clear
/// </summary>
/// <param name="radius"></param>
/// <param name="weight"></param>
private void SphereCollide(double radius, double weight)
{
UpdateGrid(radius);
var diam = radius * 2.0;
var diamSqr = diam * diam;
// calculate collisions
foreach (var v0 in _verts)
{
var p0 = v0.Position;
// search from h0
foreach (var v1 in _grid.Search(new Interval3d(p0, diam)))
{
var d = v1.Position - p0;
var m = d.SquareLength;
if (m < diamSqr && m > 0.0)
{
d *= (1.0 - diam / Math.Sqrt(m)) * 0.5 * weight;
v0.MoveSum += d;
v1.MoveSum -= d;
v0.WeightSum = v1.WeightSum = weight;
}
}
// insert h0
_grid.Insert(p0, v0);
}
_grid.Clear();
}
/// <inheritdoc />
protected override void Calculate(ReadOnlyArrayView <Body> bodies, ReadOnlyArrayView <int> indices, ArrayView <Vector3d> deltas)
{
if (_grid == null)
{
_grid = new HashGrid3d <Vector3d>(indices.Count);
}
// update grid
_grid.Scale = Radius * _radiusToGridScale;
// insert body positions
for (int i = 0; i < indices.Count; i++)
{
var p = bodies[indices[i]].Position.Current;
_grid.Insert(p, p);
}
// search from each body position
if (_parallel)
{
ForEach(Partitioner.Create(0, indices.Count), range =>
{
var i = range.Item1;
var n = range.Item2 - i;
CalculateImpl(bodies, indices.Subview(i, n), deltas.Subview(i, n));
});
}
else
{
CalculateImpl(bodies, indices, deltas);
}
_grid.Clear();
}
/// <summary>
///
/// </summary>
/// <param name="particles"></param>
private void CalculateImplParallel(IReadOnlyList <IBody> particles)
{
var diam = _radius * 2.0;
var diamSqr = diam * diam;
// insert particles
foreach (var h in Handles)
{
_grid.Insert(particles[h].Position, h);
}
// search from particles
ForEach(Partitioner.Create(0, Handles.Count), range =>
{
for (int i = range.Item1; i < range.Item2; i++)
{
var h0 = Handles[i];
var p0 = particles[h0].Position;
var deltaSum = new Vec3d();
int count = 0;
_grid.Search(new Interval3d(p0, diam), h1 =>
{
var d = particles[h1].Position - p0;
var m = d.SquareLength;
if (m < diamSqr && m > 0.0)
{
deltaSum += d * (1.0 - diam / Math.Sqrt(m));
count++;
}
return(true);
});
if (count == 0)
{
h0.Weight = 0.0;
continue;
}
h0.Delta = deltaSum * 0.5;
h0.Weight = Weight;
}
});
}
/// <summary>
///
/// </summary>
/// <param name="particles"></param>
private void CalculateImplParallel(IReadOnlyList <IBody> particles)
{
var diam = _radius * 2.0;
var diamSqr = diam * diam;
// insert all particles
foreach (var h in Handles)
{
_grid.Insert(particles[h].Position, h);
}
// search for collisions from each particle
ForEach(Partitioner.Create(0, Handles.Count), range =>
{
for (int i = range.Item1; i < range.Item2; i++)
{
var h0 = Handles[i];
var p0 = particles[h0].Position;
var deltaSum = new Vec3d();
int count = 0;
foreach (var h1 in _grid.Search(new Interval3d(p0, diam)))
{
var d = particles[h1].Position - p0;
var m = d.SquareLength;
if (m < diamSqr && m > 0.0)
{
deltaSum += d * (1.0 - diam / Math.Sqrt(m));
count++;
}
}
// no projections applied
if (count == 0)
{
h0.Skip = true;
continue;
}
h0.Delta = deltaSum * 0.5;
h0.Skip = false;
}
});
}
/*
* /// <summary>
* ///
* /// </summary>
* /// <param name="weightInterior"></param>
* /// <param name="weightBoundary"></param>
* private void LaplacianFair(double weightInterior, double weightBoundary)
* {
* for (int i = 0; i < _verts.Count; i++)
* {
* var v0 = _verts[i];
* if (v0.IsUnused) continue;
*
* if (v0.IsBoundary)
* {
* var he = v0.FirstOut;
*
* var v1 = he.PrevInFace.Start;
* var v2 = he.NextInFace.Start;
* var move = (v1.Position + v2.Position) * 0.5 - v0.Position;
*
* // apply to central vertex
* v0.MoveSum += move * weightBoundary;
* v0.WeightSum += weightBoundary;
*
* // distribute negated to neighbours
* move *= -0.5;
* v1.MoveSum += move * weightBoundary;
* v1.WeightSum += weightBoundary;
* v2.MoveSum += move * weightBoundary;
* v2.WeightSum += weightBoundary;
* }
* else
* {
* var sum = new Vec3d();
* var count = 0;
*
* foreach (var v1 in v0.ConnectedVertices)
* {
* sum += v1.Position;
* count++;
* }
*
* double t = 1.0 / count;
* var move = sum * t - v0.Position;
*
* // apply to central vertex
* v0.MoveSum += move * weightInterior;
* v0.WeightSum += weightInterior;
*
* // distribute negated to neighbours
* move *= -t;
* foreach (var v1 in v0.ConnectedVertices)
* {
* v1.MoveSum += move * weightInterior;
* v1.WeightSum += weightInterior;
* }
* }
* }
* }
*/
/// <summary>
///
/// </summary>
/// <param name="radius"></param>
/// <param name="weight"></param>
private void SphereCollideParallel(double radius, double weight)
{
UpdateGrid(radius);
var rad2 = radius * 2.0;
var rad2Sqr = rad2 * rad2;
// insert vertices
foreach (var v in _verts)
{
_grid.Insert(v.Position, v);
}
// search from each vertex and handle collisions
Parallel.ForEach(Partitioner.Create(0, _verts.Count), range =>
{
for (int i = range.Item1; i < range.Item2; i++)
{
var v0 = _verts[i];
var p0 = v0.Position;
var moveSum = new Vec3d();
int count = 0;
_grid.Search(new Interval3d(p0, rad2), v1 =>
{
var move = v1.Position - p0;
var d = move.SquareLength;
if (d < rad2Sqr && d > 0.0)
{
moveSum += move * (1.0 - rad2 / Math.Sqrt(d));
count++;
}
return(true);
});
if (count == 0)
{
continue;
}
v0.MoveSum += moveSum * weight * 0.5;
v0.WeightSum += weight;
}
});
_grid.Clear();
}
/// <summary>
///
/// </summary>
/// <param name="bodies"></param>
private void CalculateImplParallel(IReadOnlyList <IBody> bodies)
{
var diam = _radius * 2.0;
var diamSqr = diam * diam;
// insert all particles
foreach (var h in Handles)
{
_grid.Insert(bodies[h].Position, h);
}
// search for collisions from each particle
ForEach(Partitioner.Create(0, Handles.Count), range =>
{
for (int i = range.Item1; i < range.Item2; i++)
{
var h0 = Handles[i];
var p0 = bodies[h0].Position;
var deltaSum = new Vec3d();
foreach (var h1 in _grid.Search(new Interval3d(p0, diam)))
{
var d = bodies[h1].Position - p0;
var m = d.SquareLength;
if (m < diamSqr && m > 0.0)
{
deltaSum += d * (1.0 - diam / Math.Sqrt(m));
}
}
h0.Delta = deltaSum * Strength;
}
});
}