public void SimulateOneTimeStep(float dt)
{
#region Apply External Force
for (int v = 0; v < totalVerts; v++)
{
Vector3 force = Vector3.zero;
Vector3 corr;
// add gravity acceleration (f = ma)
force += gravity * meshData.particles[v].mass;
if (PBD.ExternalForce(
dt,
meshData.particles[v].predictedPos,
meshData.particles[v].velocity,
meshData.particles[v].invMass,
force,
damping,
out corr))
{
meshData.particles[v].predictedPos += corr;
}
}
#endregion
#region Apply Wind Force
float dirX = wind.GetComponentInParent <Transform>().eulerAngles.x % 360 / 360;
float dirY = wind.GetComponentInParent <Transform>().eulerAngles.y % 360 / 360;
float dirZ = wind.GetComponentInParent <Transform>().eulerAngles.z % 360 / 360;
// TODO: change this to real direction the arrow is pointing
Vector3 windDir = new Vector3(dirX, dirY, dirZ);
float windForce = wind.windMain;
for (int t = 0; t < totalTriangles; t++)
{
Triangle tri = meshData.triangles[t];
Vector3 p0 = meshData.particles[tri.p0].predictedPos;
Vector3 p1 = meshData.particles[tri.p1].predictedPos;
Vector3 p2 = meshData.particles[tri.p2].predictedPos;
float w0 = meshData.particles[tri.p0].invMass;
float w1 = meshData.particles[tri.p1].invMass;
float w2 = meshData.particles[tri.p2].invMass;
Vector3 corr0, corr1, corr2;
PBD.WindForce(
dt,
p0, w0,
p1, w1,
p2, w2,
windDir,
windForce,
out corr0, out corr1, out corr2);
meshData.particles[tri.p0].predictedPos += corr0;
meshData.particles[tri.p1].predictedPos += corr1;
meshData.particles[tri.p2].predictedPos += corr2;
}
#endregion
#region Collision Constraints
SH sh = new SH(gridSize, invGridSize, tableSize);
SPHash[] spHash = new SPHash[tableSize];
for (int v = 0; v < totalVerts; v++)
{
int hash = Mathf.Abs(sh.Hash(meshData.particles[v].predictedPos));
if (spHash[hash].indices == null)
{
spHash[hash].indices = new List <int>();
}
spHash[hash].indices.Add(meshData.particles[v].idx);
}
for (int t = 0; t < totalTriangles; t++)
{
Triangle tri = meshData.triangles[t];
Vector3 p0 = meshData.particles[tri.p0].predictedPos;
Vector3 p1 = meshData.particles[tri.p1].predictedPos;
Vector3 p2 = meshData.particles[tri.p2].predictedPos;
float w0 = meshData.particles[tri.p0].invMass;
float w1 = meshData.particles[tri.p1].invMass;
float w2 = meshData.particles[tri.p2].invMass;
List <int> hashes = sh.TriangleBoundingBoxHashes(p0, p1, p2);
for (int h = 0; h < hashes.Count; h++)
{
if (spHash[h].indices != null)
{
for (int sph = 0; sph < spHash[h].indices.Count; sph++)
{
int idx = spHash[h].indices[sph];
if (
idx != meshData.particles[tri.p0].idx &&
idx != meshData.particles[tri.p1].idx &&
idx != meshData.particles[tri.p2].idx)
{
Vector3 p = meshData.particles[idx].predictedPos;
float w = meshData.particles[idx].invMass;
Vector3 corr, corr0, corr1, corr2;
if (PBD.TrianglePointDistanceConstraint(
p, w,
p0, w0,
p1, w1,
p2, w2,
thickness, 1f, 0.0f,
out corr, out corr0, out corr1, out corr2))
{
meshData.particles[idx].predictedPos += corr;
meshData.particles[tri.p0].predictedPos += corr0;
meshData.particles[tri.p1].predictedPos += corr1;
meshData.particles[tri.p2].predictedPos += corr2;
}
}
}
}
}
}
#endregion
#region Project Constraints
for (int iter = 0; iter < iterationSteps; iter++)
{
#region Distance Constraint
for (int e = 0; e < totalEdges; e++)
{
Vector3 corr0, corr1;
Edge edge = meshData.edges[e];
Vector3 p0 = meshData.particles[edge.p0].predictedPos;
Vector3 p1 = meshData.particles[edge.p1].predictedPos;
float w0 = meshData.particles[edge.p0].invMass;
float w1 = meshData.particles[edge.p1].invMass;
if (PBD.DistanceConstraint(
p0, w0,
p1, w1,
edge.restLength,
stretchStiffness,
compressionStiffness,
out corr0, out corr1))
{
meshData.particles[edge.p0].predictedPos += corr0;
meshData.particles[edge.p1].predictedPos += corr1;
}
}
#endregion
#region Dihedral Constraint
for (int n = 0; n < totalNeighborTriangles; n++)
{
Vector3 corr0, corr1, corr2, corr3;
NeighborTriangles neighbor = meshData.neighborTriangles[n];
Vector3 p0 = meshData.particles[neighbor.p0].predictedPos;
Vector3 p1 = meshData.particles[neighbor.p1].predictedPos;
Vector3 p2 = meshData.particles[neighbor.p2].predictedPos;
Vector3 p3 = meshData.particles[neighbor.p3].predictedPos;
float w0 = meshData.particles[neighbor.p0].invMass;
float w1 = meshData.particles[neighbor.p1].invMass;
float w2 = meshData.particles[neighbor.p2].invMass;
float w3 = meshData.particles[neighbor.p3].invMass;
if (PBD.DihedralConstraint(
p0, w0,
p1, w1,
p2, w2,
p3, w3,
neighbor.restAngle,
bendingStiffness,
out corr0, out corr1, out corr2, out corr3))
{
meshData.particles[neighbor.p0].predictedPos += corr0;
meshData.particles[neighbor.p1].predictedPos += corr1;
meshData.particles[neighbor.p2].predictedPos += corr2;
meshData.particles[neighbor.p3].predictedPos += corr3;
}
}
#endregion
}
#endregion
}
