private IEnumerator CreateInitialDistanceConstraints(List <int> edges)
{
List <int> particleIndices = new List <int>();
List <int> constraintIndices = new List <int>();
for (int i = 0; i < edges.Count; i++)
{
HalfEdgeMesh.HalfEdge hedge = topology.halfEdges[edges[i]];
// ignore borders:
if (hedge.face < 0)
{
continue;
}
particleIndices.Add(topology.GetHalfEdgeStartVertex(hedge));
particleIndices.Add(hedge.endVertex);
constraintIndices.Add(constraintIndices.Count * 2);
if (i % 500 == 0)
{
yield return(new CoroutineJob.ProgressInfo("ObiCloth: generating structural constraints...", i / (float)topology.halfEdges.Count));
}
}
constraintIndices.Add(constraintIndices.Count * 2);
int[] constraintColors = GraphColoring.Colorize(particleIndices.ToArray(), constraintIndices.ToArray());
for (int i = 0; i < constraintColors.Length; ++i)
{
int color = constraintColors[i];
int cIndex = constraintIndices[i];
// Add a new batch if needed:
if (color >= distanceConstraintsData.GetBatchCount())
{
distanceConstraintsData.AddBatch(new ObiDistanceConstraintsBatch());
}
HalfEdgeMesh.HalfEdge hedge = topology.halfEdges[edges[i]];
HalfEdgeMesh.Vertex startVertex = topology.vertices[topology.GetHalfEdgeStartVertex(hedge)];
HalfEdgeMesh.Vertex endVertex = topology.vertices[hedge.endVertex];
distanceConstraintsData.batches[color].AddConstraint(new Vector2Int(particleIndices[cIndex], particleIndices[cIndex + 1]),
Vector3.Distance(Vector3.Scale(scale, startVertex.position), Vector3.Scale(scale, endVertex.position)));
distanceConstraintMap[hedge.index] = new Vector2Int(color, distanceConstraintsData.batches[color].constraintCount - 1);
}
// Set initial amount of active constraints:
for (int i = 0; i < distanceConstraintsData.batches.Count; ++i)
{
distanceConstraintsData.batches[i].activeConstraintCount = distanceConstraintsData.batches[i].constraintCount;
}
}
/**
* Automatically generates tether constraints for the cloth.
* Partitions fixed particles into "islands", then generates up to maxTethers constraints for each
* particle, linking it to the closest point in each island.
*/
public override void GenerateTethers(bool[] selected)
{
tetherConstraintsData = new ObiTetherConstraintsData();
// generate disjoint groups of particles (islands)
List <HashSet <int> > islands = GenerateIslands(System.Linq.Enumerable.Range(0, topology.vertices.Count), null);
// generate tethers for each one:
List <int> particleIndices = new List <int>();
foreach (HashSet <int> island in islands)
{
GenerateTethersForIsland(island, particleIndices, selected, 4);
}
// for tethers, it's easy to use the optimal amount of colors analytically.
if (particleIndices.Count > 0)
{
int color = 0;
int lastParticle = particleIndices[0];
for (int i = 0; i < particleIndices.Count; i += 2)
{
if (particleIndices[i] != lastParticle)
{
lastParticle = particleIndices[i];
color = 0;
}
// Add a new batch if needed:
if (color >= tetherConstraintsData.GetBatchCount())
{
tetherConstraintsData.AddBatch(new ObiTetherConstraintsBatch());
}
HalfEdgeMesh.Vertex startVertex = topology.vertices[particleIndices[i]];
HalfEdgeMesh.Vertex endVertex = topology.vertices[particleIndices[i + 1]];
tetherConstraintsData.batches[color].AddConstraint(new Vector2Int(particleIndices[i], particleIndices[i + 1]),
Vector3.Distance(Vector3.Scale(scale, startVertex.position), Vector3.Scale(scale, endVertex.position)),
1);
color++;
}
}
// Set initial amount of active constraints:
for (int i = 0; i < tetherConstraintsData.batches.Count; ++i)
{
tetherConstraintsData.batches[i].activeConstraintCount = tetherConstraintsData.batches[i].constraintCount;
}
}
private void ClassifyFaces(HalfEdgeMesh.Vertex vertex,
Plane plane,
List <HalfEdgeMesh.Face> side1,
List <HalfEdgeMesh.Face> side2)
{
foreach (HalfEdgeMesh.Face face in m_TearableBlueprintInstance.topology.GetNeighbourFacesEnumerator(vertex))
{
HalfEdgeMesh.HalfEdge e1 = m_TearableBlueprintInstance.topology.halfEdges[face.halfEdge];
HalfEdgeMesh.HalfEdge e2 = m_TearableBlueprintInstance.topology.halfEdges[e1.nextHalfEdge];
HalfEdgeMesh.HalfEdge e3 = m_TearableBlueprintInstance.topology.halfEdges[e2.nextHalfEdge];
// Skip this face if it doesn't contain the vertex being split.
// This can happen because edge pair links are not updated in a vertex split operation,
// so split vertices still "see" faces at the other side of the cut as adjacent.
if (e1.endVertex != vertex.index &&
e2.endVertex != vertex.index &&
e3.endVertex != vertex.index)
{
continue;
}
// calculate actual face center from deformed vertex positions:
Vector3 faceCenter = (m_Solver.positions[solverIndices[e1.endVertex]] +
m_Solver.positions[solverIndices[e2.endVertex]] +
m_Solver.positions[solverIndices[e3.endVertex]]) * 0.33f;
if (plane.GetSide(faceCenter))
{
side1.Add(face);
}
else
{
side2.Add(face);
}
}
}
private List <HashSet <int> > GenerateIslands(IEnumerable <int> particles, Func <int, bool> condition)
{
List <HashSet <int> > islands = new List <HashSet <int> >();
// Partition fixed particles into islands:
foreach (int i in particles)
{
HalfEdgeMesh.Vertex vertex = topology.vertices[i];
if (condition != null && !condition(i))
{
continue;
}
int assignedIsland = -1;
// keep a list of islands to merge with ours:
List <int> mergeableIslands = new List <int>();
// See if any of our neighbors is part of an island:
foreach (HalfEdgeMesh.Vertex n in topology.GetNeighbourVerticesEnumerator(vertex))
{
for (int k = 0; k < islands.Count; ++k)
{
if (islands[k].Contains(n.index))
{
// if we are not in an island yet, pick this one:
if (assignedIsland < 0)
{
assignedIsland = k;
islands[k].Add(i);
}
// if we already are in an island, we will merge this newfound island with ours:
else if (assignedIsland != k && !mergeableIslands.Contains(k))
{
mergeableIslands.Add(k);
}
}
}
}
// merge islands with the assigned one:
foreach (int merge in mergeableIslands)
{
islands[assignedIsland].UnionWith(islands[merge]);
}
// remove merged islands:
mergeableIslands.Sort();
mergeableIslands.Reverse();
foreach (int merge in mergeableIslands)
{
islands.RemoveAt(merge);
}
// If no adjacent particle is in an island, create a new one:
if (assignedIsland < 0)
{
islands.Add(new HashSet <int>()
{
i
});
}
}
return(islands);
}
protected virtual IEnumerator CreateBendingConstraints()
{
bendConstraintsData = new ObiBendConstraintsData();
List <int> particleIndices = new List <int>();
List <int> constraintIndices = new List <int>();
Dictionary <int, int> cons = new Dictionary <int, int>();
for (int i = 0; i < topology.vertices.Count; i++)
{
HalfEdgeMesh.Vertex vertex = topology.vertices[i];
foreach (HalfEdgeMesh.Vertex n1 in topology.GetNeighbourVerticesEnumerator(vertex))
{
float cosBest = 0;
HalfEdgeMesh.Vertex vBest = n1;
foreach (HalfEdgeMesh.Vertex n2 in topology.GetNeighbourVerticesEnumerator(vertex))
{
float cos = Vector3.Dot((n1.position - vertex.position).normalized,
(n2.position - vertex.position).normalized);
if (cos < cosBest)
{
cosBest = cos;
vBest = n2;
}
}
if (!cons.ContainsKey(vBest.index) || cons[vBest.index] != n1.index)
{
cons[n1.index] = vBest.index;
particleIndices.Add(n1.index);
particleIndices.Add(vBest.index);
particleIndices.Add(vertex.index);
constraintIndices.Add(constraintIndices.Count * 3);
}
}
if (i % 500 == 0)
{
yield return(new CoroutineJob.ProgressInfo("ObiCloth: adding bend constraints...", i / (float)topology.vertices.Count));
}
}
constraintIndices.Add(constraintIndices.Count * 3);
int[] constraintColors = GraphColoring.Colorize(particleIndices.ToArray(), constraintIndices.ToArray());
for (int i = 0; i < constraintColors.Length; ++i)
{
int color = constraintColors[i];
int cIndex = constraintIndices[i];
// Add a new batch if needed:
if (color >= bendConstraintsData.GetBatchCount())
{
bendConstraintsData.AddBatch(new ObiBendConstraintsBatch());
}
HalfEdgeMesh.Vertex n1 = topology.vertices[particleIndices[cIndex]];
HalfEdgeMesh.Vertex vBest = topology.vertices[particleIndices[cIndex + 1]];
HalfEdgeMesh.Vertex vertex = topology.vertices[particleIndices[cIndex + 2]];
Vector3 n1Pos = Vector3.Scale(scale, n1.position);
Vector3 bestPos = Vector3.Scale(scale, vBest.position);
Vector3 vertexPos = Vector3.Scale(scale, vertex.position);
float restBend = ObiUtils.RestBendingConstraint(n1Pos, bestPos, vertexPos);
bendConstraintsData.batches[color].AddConstraint(new Vector3Int(particleIndices[cIndex], particleIndices[cIndex + 1], particleIndices[cIndex + 2]), restBend);
}
// Set initial amount of active constraints:
for (int i = 0; i < bendConstraintsData.batches.Count; ++i)
{
bendConstraintsData.batches[i].activeConstraintCount = bendConstraintsData.batches[i].constraintCount;
}
}
protected override IEnumerator Initialize()
{
if (inputMesh == null || !inputMesh.isReadable)
{
// TODO: return an error in the coroutine.
Debug.LogError("The input mesh is null, or not readable.");
yield break;
}
ClearParticleGroups();
topology = new HalfEdgeMesh();
topology.inputMesh = inputMesh;
topology.Generate();
positions = new Vector3[topology.vertices.Count];
restPositions = new Vector4[topology.vertices.Count];
velocities = new Vector3[topology.vertices.Count];
invMasses = new float[topology.vertices.Count];
principalRadii = new Vector3[topology.vertices.Count];
phases = new int[topology.vertices.Count];
colors = new Color[topology.vertices.Count];
areaContribution = new float[topology.vertices.Count];
// Create a particle for each vertex:
m_ActiveParticleCount = topology.vertices.Count;
for (int i = 0; i < topology.vertices.Count; i++)
{
HalfEdgeMesh.Vertex vertex = topology.vertices[i];
// Get the particle's area contribution.
areaContribution[i] = 0;
foreach (HalfEdgeMesh.Face face in topology.GetNeighbourFacesEnumerator(vertex))
{
areaContribution[i] += topology.GetFaceArea(face) / 3;
}
// Get the shortest neighbour edge, particle radius will be half of its length.
float minEdgeLength = Single.MaxValue;
foreach (HalfEdgeMesh.HalfEdge edge in topology.GetNeighbourEdgesEnumerator(vertex))
{
// vertices at each end of the edge:
Vector3 v1 = Vector3.Scale(scale, topology.vertices[topology.GetHalfEdgeStartVertex(edge)].position);
Vector3 v2 = Vector3.Scale(scale, topology.vertices[edge.endVertex].position);
minEdgeLength = Mathf.Min(minEdgeLength, Vector3.Distance(v1, v2));
}
invMasses[i] = (/*skinnedMeshRenderer == null &&*/ areaContribution[i] > 0) ? (1.0f / (DEFAULT_PARTICLE_MASS * areaContribution[i])) : 0;
positions[i] = Vector3.Scale(scale, vertex.position);
restPositions[i] = positions[i];
restPositions[i][3] = 1; // activate rest position.
principalRadii[i] = Vector3.one * minEdgeLength * 0.5f;
phases[i] = ObiUtils.MakePhase(1, /*selfCollisions ? Oni.ParticlePhase.SelfCollide : 0*/ 0);
colors[i] = Color.white;
if (i % 500 == 0)
{
yield return(new CoroutineJob.ProgressInfo("ObiCloth: generating particles...", i / (float)topology.vertices.Count));
}
}
// Deformable triangles:
IEnumerator dt = GenerateDeformableTriangles();
while (dt.MoveNext())
{
yield return(dt.Current);
}
// Create distance constraints:
IEnumerator dc = CreateDistanceConstraints();
while (dc.MoveNext())
{
yield return(dc.Current);
}
// Create aerodynamic constraints:
IEnumerator ac = CreateAerodynamicConstraints();
while (ac.MoveNext())
{
yield return(ac.Current);
}
// Create bending constraints:
IEnumerator bc = CreateBendingConstraints();
while (bc.MoveNext())
{
yield return(bc.Current);
}
// Create volume constraints:
IEnumerator vc = CreateVolumeConstraints();
while (vc.MoveNext())
{
yield return(vc.Current);
}
}
private bool SplitTopologyAtVertex(int vertexIndex,
Plane plane,
List <HalfEdgeMesh.Face> updatedFaces,
HashSet <int> updatedEdgeIndices)
{
if (vertexIndex < 0 || vertexIndex >= m_TearableBlueprintInstance.topology.vertices.Count)
{
return(false);
}
updatedFaces.Clear();
updatedEdgeIndices.Clear();
HalfEdgeMesh.Vertex vertex = m_TearableBlueprintInstance.topology.vertices[vertexIndex];
// classify adjacent faces depending on which side of the plane they're at:
var otherSide = new List <HalfEdgeMesh.Face>();
ClassifyFaces(vertex, plane, updatedFaces, otherSide);
// guard against pathological case in which all particles are in one side of the plane:
if (otherSide.Count == 0 || updatedFaces.Count == 0)
{
return(false);
}
// create a new vertex:
var newVertex = new HalfEdgeMesh.Vertex();
newVertex.position = vertex.position;
newVertex.index = m_TearableBlueprintInstance.topology.vertices.Count;
newVertex.halfEdge = vertex.halfEdge;
// rearrange edges at the updated side:
foreach (HalfEdgeMesh.Face face in updatedFaces)
{
// find half edges that start and end at the split vertex:
HalfEdgeMesh.HalfEdge e1 = m_TearableBlueprintInstance.topology.halfEdges[face.halfEdge];
HalfEdgeMesh.HalfEdge e2 = m_TearableBlueprintInstance.topology.halfEdges[e1.nextHalfEdge];
HalfEdgeMesh.HalfEdge e3 = m_TearableBlueprintInstance.topology.halfEdges[e2.nextHalfEdge];
var in_ = e1;
var out_ = e2;
if (e1.endVertex == vertex.index)
{
in_ = e1;
}
else if (m_TearableBlueprintInstance.topology.GetHalfEdgeStartVertex(e1) == vertex.index)
{
out_ = e1;
}
if (e2.endVertex == vertex.index)
{
in_ = e2;
}
else if (m_TearableBlueprintInstance.topology.GetHalfEdgeStartVertex(e2) == vertex.index)
{
out_ = e2;
}
if (e3.endVertex == vertex.index)
{
in_ = e3;
}
else if (m_TearableBlueprintInstance.topology.GetHalfEdgeStartVertex(e3) == vertex.index)
{
out_ = e3;
}
// stitch edges to new vertex:
in_.endVertex = newVertex.index;
m_TearableBlueprintInstance.topology.halfEdges[in_.index] = in_;
newVertex.halfEdge = out_.index;
// store edges to be updated:
updatedEdgeIndices.UnionWith(new int[]
{
in_.index, in_.pair, out_.index, out_.pair
});
}
// add new vertex:
m_TearableBlueprintInstance.topology.vertices.Add(newVertex);
m_TearableBlueprintInstance.topology.restNormals.Add(m_TearableBlueprintInstance.topology.restNormals[vertexIndex]);
m_TearableBlueprintInstance.topology.restOrientations.Add(m_TearableBlueprintInstance.topology.restOrientations[vertexIndex]);
//TODO: update mesh info. (mesh cannot be closed now)
return(true);
}
