(23-09-2020, 03:17 PM)josemendez Wrote: Here's a sample script (for Obi 5.6) using the particle API and contact callbacks to grab any particles in contact with a collider/trigger.
Simply add it to a collider, and drag/drop the solver reference onto it. Then you can call its Grab() and Release() methods to grab any particles in contact with that collider, and release them.
Code:using UnityEngine;
using System.Collections.Generic;
using Obi;
/**
* Sample component that makes a collider "grab" any particle it touches (regardless of which Actor it belongs to).
*/
[RequireComponent(typeof(ObiCollider))]
public class ObiContactGrabber : MonoBehaviour
{
public ObiSolver solver;
/**
* Helper class that stores the index of a particle in the solver, its position in the grabber's local space, and its inverse mass previous to being grabbed.
* This makes it easy to tell if a particle has been grabbed, update its position while grabbing, and restore its mass after being released.
*/
private class GrabbedParticle : IEqualityComparer<GrabbedParticle>
{
public int index;
public float invMass;
public Vector3 localPosition;
public GrabbedParticle(int index, float invMass)
{
this.index = index;
this.invMass = invMass;
}
public bool Equals(GrabbedParticle x, GrabbedParticle y)
{
return x.index == y.index;
}
public int GetHashCode(GrabbedParticle obj)
{
return index;
}
}
private ObiSolver.ObiCollisionEventArgs collisionEvent; /**< store the current collision event*/
private ObiCollider localCollider; /**< the collider on this gameObject.*/
private HashSet<GrabbedParticle> grabbedParticles = new HashSet<GrabbedParticle>(); /**< set to store all currently grabbed particles.*/
private HashSet<ObiActor> grabbedActors = new HashSet<ObiActor>(); /**< set of softbodies grabbed during this step.*/
private Matrix4x4 grabber2Solver;
private Matrix4x4 solver2Grabber;
private void Awake()
{
localCollider = GetComponent<ObiCollider>();
}
private void OnEnable()
{
if (solver != null)
solver.OnCollision += Solver_OnCollision;
}
private void OnDisable()
{
if (solver != null)
solver.OnCollision -= Solver_OnCollision;
}
private void Solver_OnCollision(object sender, Obi.ObiSolver.ObiCollisionEventArgs e)
{
// Calculate transform matrix from grabber to world space (Note: if using local space simulation, postmultiply with solver.transform.localToWorldMatrix)
solver2Grabber = transform.worldToLocalMatrix * solver.transform.localToWorldMatrix;
// and its inverse:
grabber2Solver = solver2Grabber.inverse;
collisionEvent = e;
}
private void UpdateParticleProperties()
{
// Update rest shape matching of all grabbed softbodies:
foreach (ObiActor actor in grabbedActors)
{
actor.UpdateParticleProperties();
}
}
/**
* Creates and stores a GrabbedParticle from the particle at the given index.
* Returns true if we sucessfully grabbed a particle, false if the particle was already grabbed.
*/
private bool GrabParticle(int index)
{
GrabbedParticle p = new GrabbedParticle(index, solver.invMasses[index]);
// in case this particle has not been grabbed yet:
if (!grabbedParticles.Contains(p))
{
// record the particle's position relative to the grabber, and store it.
p.localPosition = solver2Grabber.MultiplyPoint3x4(solver.positions[index]);
grabbedParticles.Add(p);
// Set inv mass and velocity to zero:
solver.invMasses[index] = 0;
solver.velocities[index] = Vector4.zero;
return true;
}
return false;
}
/**
* Grabs all particles currently touching the grabber.
*/
public void Grab()
{
grabbedActors.Clear();
var world = ObiColliderWorld.GetInstance();
if (solver != null && collisionEvent != null)
{
foreach (Oni.Contact contact in collisionEvent.contacts)
{
// this one is an actual collision:
if (contact.distance < 0.01f)
{
var contactCollider = world.colliderHandles[contact.other].owner;
// if the current contact references our collider, proceed to grab the particle.
if (contactCollider == localCollider)
{
// try to grab the particle, if not already grabbed.
if (GrabParticle(contact.particle))
grabbedActors.Add(solver.particleToActor[contact.particle].actor);
}
}
}
}
UpdateParticleProperties();
}
/**
* Releases all currently grabbed particles. This boils down to simply resetting their invMass.
*/
public void Release()
{
// Restore the inverse mass of all grabbed particles, so dynamics affect them.
foreach (GrabbedParticle p in grabbedParticles)
solver.invMasses[p.index] = p.invMass;
UpdateParticleProperties();
grabbedActors.Clear();
grabbedParticles.Clear();
}
/**
* Updates the position of the grabbed particles.
*/
private void FixedUpdate()
{
foreach (GrabbedParticle p in grabbedParticles)
solver.positions[p.index] = grabber2Solver.MultiplyPoint3x4(p.localPosition);
}
}
I;m getting the following error using this code with Obi Rope 5.3
Error CS0103 The name 'ObiColliderWorld' does not exist in the current context
Is this normal?