Garbage from subscribing to collision events

[josemendez]

Can I get a Hallelujah! THANK YOU

This has been a long sought-after thing for us too!

Ok, so here's the patch and installation instructions. It will be a little hard to apply, as you must manually modify the existing ObiSolver.cs file in a couple places.

1.- Replace the existing ObiCollisionEventArgs and ObiFluidEventArgs class implementations (found at the beginning of ObiSolver.cs) with this:

Code:

public class ObiCollisionEventArgs : EventArgs{
        public ObiList<Oni.Contact> contacts = new ObiList<Oni.Contact>();    /**< collision contacts.*/
    }

    public class ObiFluidEventArgs : EventArgs{

        public ObiList<int> indices = new ObiList<int>();            /**< fluid particle indices.*/
        public ObiList<Vector4> vorticities = new ObiList<Vector4>();
        public ObiList<float> densities = new ObiList<float>();

    }

       private ObiCollisionEventArgs collisionArgs = new ObiCollisionEventArgs();
    private ObiFluidEventArgs fluidArgs = new ObiFluidEventArgs();

2.- Replace TriggerFluidUpdateEvents and TriggerCollisionEvents functions with these:

Code:

private void TriggerFluidUpdateEvents(){

        int numFluidParticles = Oni.GetConstraintCount(oniSolver,(int)Oni.ConstraintType.Density);
        
        if (numFluidParticles > 0 && OnFluidUpdated != null){

            fluidArgs.indices.SetCount(numFluidParticles);
            fluidArgs.vorticities.SetCount(maxParticles);
            fluidArgs.densities.SetCount(maxParticles);

            Oni.GetActiveConstraintIndices(oniSolver,fluidArgs.indices.Data,numFluidParticles,(int)Oni.ConstraintType.Density);
            Oni.GetParticleVorticities(oniSolver,fluidArgs.vorticities.Data,maxParticles,0);
            Oni.GetParticleDensities(oniSolver,fluidArgs.densities.Data,maxParticles,0);

            OnFluidUpdated(this,fluidArgs);
        }
    }

    private void TriggerCollisionEvents(){
    
        int numCollisions = Oni.GetConstraintCount(oniSolver,(int)Oni.ConstraintType.Collision);

        if (OnCollision != null){

            if (numCollisions > 0)
            {
                collisionArgs.contacts.SetCount(numCollisions);
                Oni.GetCollisionContacts(oniSolver,collisionArgs.contacts.Data,numCollisions);
            }
    
            OnCollision(this,collisionArgs);

        }
    }

Lastly, include the ObiList.cs file you'll find attached in your project. That should be it! Collision and fluid update events will only generate a small amount of garbage in certain frames, when the amount of contacts/particles grows past the arrays capacity. Most frames, zero garbage will be generated.


Let me know if you have any issues with this.