public void LateUpdate()
{
ClearMeshData();
if (section == null)
{
return;
}
IList <List <Vector3> > segments = cable.sampledCable.Segments;
int sectionSegments = section.Segments;
int verticesPerSection = sectionSegments + 1; // the last vertex in each section must be duplicated, due to uv wraparound.
float vCoord = -uvScale.y * cable.RestLength; // v texture coordinate.
int sectionIndex = 0;
float strain = cable.sampledCable.Length / cable.RestLength;
// we will define and transport a reference frame along the curve using parallel transport method:
if (frame == null)
{
frame = new CurveFrame();
}
Vector4 texTangent = Vector4.zero;
Vector2 uv = Vector2.zero;
Matrix4x4 w2l = transform.worldToLocalMatrix;
for (int k = 0; k < segments.Count; ++k)
{
List <Vector3> samples = segments[k];
// Reinitialize frame for each segment.
frame.Reset();
for (int i = 0; i < samples.Count; ++i)
{
// Calculate previous and next curve indices:
int nextIndex = Mathf.Min(i + 1, samples.Count - 1);
int prevIndex = Mathf.Max(i - 1, 0);
Vector3 point = w2l.MultiplyPoint3x4(samples[i]);
Vector3 prevPoint = w2l.MultiplyPoint3x4(samples[prevIndex]);
Vector3 nextPoint = w2l.MultiplyPoint3x4(samples[nextIndex]);
Vector3 nextV = (nextPoint - point).normalized;
Vector3 prevV = (point - prevPoint).normalized;
Vector3 tangent = nextV + prevV;
// update frame:
frame.Transport(point, tangent, 0);
// advance v texcoord:
vCoord += uvScale.y * (Vector3.Distance(point, prevPoint) / strain);
// Loop around each segment:
for (int j = 0; j <= sectionSegments; ++j)
{
vertices.Add(frame.position + (section.vertices[j].x * frame.normal + section.vertices[j].y * frame.binormal) * thickness);
normals.Add(vertices[vertices.Count - 1] - frame.position);
texTangent = -Vector3.Cross(normals[normals.Count - 1], frame.tangent);
texTangent.w = 1;
tangents.Add(texTangent);
uv.Set((j / (float)sectionSegments) * uvScale.x, vCoord);
uvs.Add(uv);
if (j < sectionSegments && i < samples.Count - 1)
{
tris.Add(sectionIndex * verticesPerSection + j);
tris.Add(sectionIndex * verticesPerSection + (j + 1));
tris.Add((sectionIndex + 1) * verticesPerSection + j);
tris.Add(sectionIndex * verticesPerSection + (j + 1));
tris.Add((sectionIndex + 1) * verticesPerSection + (j + 1));
tris.Add((sectionIndex + 1) * verticesPerSection + j);
}
}
sectionIndex++;
}
}
CommitMeshData();
}
/**
* Generates the particle based physical representation of the rope. This is the initialization method for the rope object
* and should not be called directly once the object has been created.
*/
protected override IEnumerator Initialize()
{
initialized = false;
initializing = true;
interParticleDistance = -1;
RemoveFromSolver(null);
if (ropePath == null)
{
Debug.LogError("Cannot initialize rope. There's no ropePath present. Please provide a spline to define the shape of the rope");
yield break;
}
ropePath.RecalculateSplineLenght(0.00001f, 7);
closed = ropePath.closed;
restLength = ropePath.Length;
usedParticles = Mathf.CeilToInt(restLength / thickness * resolution) + (closed ? 0:1);
totalParticles = usedParticles;
active = new bool[totalParticles];
positions = new Vector3[totalParticles];
orientations = new Quaternion[totalParticles];
velocities = new Vector3[totalParticles];
angularVelocities = new Vector3[totalParticles];
invMasses = new float[totalParticles];
invRotationalMasses = new float[totalParticles];
principalRadii = new Vector3[totalParticles];
phases = new int[totalParticles];
restPositions = new Vector4[totalParticles];
restOrientations = new Quaternion[totalParticles];
colors = new Color[totalParticles];
int numSegments = usedParticles - (closed ? 0:1);
if (numSegments > 0)
{
interParticleDistance = restLength / (float)numSegments;
}
else
{
interParticleDistance = 0;
}
float radius = interParticleDistance * resolution;
for (int i = 0; i < usedParticles; i++)
{
active[i] = true;
invMasses[i] = 1.0f / DEFAULT_PARTICLE_MASS;
invRotationalMasses[i] = 1.0f / DEFAULT_PARTICLE_ROTATIONAL_MASS;
float mu = ropePath.GetMuAtLenght(interParticleDistance * i);
positions[i] = transform.InverseTransformPoint(ropePath.transform.TransformPoint(ropePath.GetPositionAt(mu)));
principalRadii[i] = Vector3.one * radius;
phases[i] = Oni.MakePhase(1, selfCollisions?Oni.ParticlePhase.SelfCollide:0);
colors[i] = Color.white;
if (i % 100 == 0)
{
yield return(new CoroutineJob.ProgressInfo("ObiRod: generating particles...", i / (float)usedParticles));
}
}
StretchShearConstraints.Clear();
ObiStretchShearConstraintBatch stretchBatch = new ObiStretchShearConstraintBatch(false, false, MIN_YOUNG_MODULUS, MAX_YOUNG_MODULUS);
StretchShearConstraints.AddBatch(stretchBatch);
// rotation minimizing frame:
CurveFrame frame = new CurveFrame();
frame.Reset();
for (int i = 0; i < numSegments; i++)
{
int next = (i + 1) % (ropePath.closed ? usedParticles:usedParticles + 1);
float mu = ropePath.GetMuAtLenght(interParticleDistance * i);
Vector3 normal = transform.InverseTransformVector(ropePath.transform.TransformVector(ropePath.GetNormalAt(mu)));
frame.Transport(positions[i], (positions[next] - positions[i]).normalized, 0);
orientations[i] = Quaternion.LookRotation(frame.tangent, normal);
restOrientations[i] = orientations[i];
// Also set the orientation of the next particle. If it is not the last one, we will overwrite it.
// This makes sure that open rods provide an orientation for their last particle (or rather, a phantom segment past the last particle).
orientations[next] = orientations[i];
restOrientations[next] = orientations[i];
stretchBatch.AddConstraint(i, next, interParticleDistance, Vector3.one);
if (i % 500 == 0)
{
yield return(new CoroutineJob.ProgressInfo("ObiRod: generating structural constraints...", i / (float)numSegments));
}
}
BendTwistConstraints.Clear();
ObiBendTwistConstraintBatch twistBatch = new ObiBendTwistConstraintBatch(false, false, MIN_YOUNG_MODULUS, MAX_YOUNG_MODULUS);
BendTwistConstraints.AddBatch(twistBatch);
// the last bend constraint couples the last segment and a phantom segment past the last particle.
for (int i = 0; i < numSegments; i++)
{
int next = (i + 1) % (ropePath.closed ? usedParticles:usedParticles + 1);
Quaternion darboux = keepInitialShape ? ObiUtils.RestDarboux(orientations[i], orientations[next]) : Quaternion.identity;
twistBatch.AddConstraint(i, next, darboux, Vector3.one);
if (i % 500 == 0)
{
yield return(new CoroutineJob.ProgressInfo("ObiRod: generating structural constraints...", i / (float)numSegments));
}
}
ChainConstraints.Clear();
ObiChainConstraintBatch chainBatch = new ObiChainConstraintBatch(false, false, MIN_YOUNG_MODULUS, MAX_YOUNG_MODULUS);
ChainConstraints.AddBatch(chainBatch);
int[] indices = new int[usedParticles + (closed ? 1:0)];
for (int i = 0; i < usedParticles; ++i)
{
indices[i] = i;
}
// Add the first particle as the last index of the chain, if closed.
if (closed)
{
indices[usedParticles] = 0;
}
chainBatch.AddConstraint(indices, interParticleDistance, 1, 1);
// Initialize tether constraints:
TetherConstraints.Clear();
// Initialize pin constraints:
PinConstraints.Clear();
ObiPinConstraintBatch pinBatch = new ObiPinConstraintBatch(false, false, MIN_YOUNG_MODULUS, MAX_YOUNG_MODULUS);
PinConstraints.AddBatch(pinBatch);
initializing = false;
initialized = true;
RegenerateRestPositions();
}