/**
* Generates new valid rest positions for the entire rope.
*/
public override void RegenerateRestPositions()
{
ObiStretchShearConstraintBatch distanceBatch = StretchShearConstraints.GetFirstBatch();
// Iterate trough all distance constraints in order:
int particle = -1;
int lastParticle = -1;
float accumulatedDistance = 0;
for (int i = 0; i < distanceBatch.ConstraintCount; ++i)
{
if (i == 0)
{
lastParticle = particle = distanceBatch.springIndices[i * 2];
restPositions[particle] = new Vector4(0, 0, 0, 1);
}
accumulatedDistance += Mathf.Min(interParticleDistance, principalRadii[particle][0], principalRadii[lastParticle][0]);
particle = distanceBatch.springIndices[i * 2 + 1];
restPositions[particle] = Vector3.right * accumulatedDistance;
restPositions[particle][3] = 1; // activate rest position
}
PushDataToSolver(ParticleData.REST_POSITIONS);
}
/**
* Returns the rest length of a structural constraint
*/
public override float GetStructuralConstraintRestLength(int constraintIndex)
{
ObiStretchShearConstraintBatch distanceBatch = StretchShearConstraints.GetFirstBatch();
if (distanceBatch != null && constraintIndex >= 0 && constraintIndex < distanceBatch.ConstraintCount)
{
return(distanceBatch.restLengths[constraintIndex]);
}
return(0);
}
/**
* Returns the index of the structural constraint at a given normalized rope coordinate.
*/
public override int GetConstraintIndexAtNormalizedCoordinate(float coord)
{
ObiStretchShearConstraintBatch distanceBatch = StretchShearConstraints.GetFirstBatch();
if (distanceBatch != null)
{
float mu = coord * distanceBatch.ConstraintCount;
return(Mathf.Clamp(Mathf.FloorToInt(mu), 0, distanceBatch.ConstraintCount - 1));
}
return(-1);
}
/**
* Returns the particle indices affected by a structural constraint
*/
public override bool GetStructuralConstraintParticles(int constraintIndex, ref int particleIndex1, ref int particleIndex2)
{
ObiStretchShearConstraintBatch distanceBatch = StretchShearConstraints.GetFirstBatch();
if (distanceBatch != null && constraintIndex >= 0 && constraintIndex < distanceBatch.ConstraintCount)
{
particleIndex1 = distanceBatch.springIndices[constraintIndex * 2];
particleIndex2 = distanceBatch.springIndices[constraintIndex * 2 + 1];
return(true);
}
return(false);
}
/**
* 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:
ObiCurveFrame frame = new ObiCurveFrame();
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, Quaternion.identity, 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();
}
/**
* Returns the amount of structural constraints in the rope.
*/
public override int GetStructuralConstraintCount()
{
ObiStretchShearConstraintBatch distanceBatch = StretchShearConstraints.GetFirstBatch();
return(distanceBatch != null ? distanceBatch.ConstraintCount:0);
}
