CODEWITHSUNDEEP
c++sdkcollisionlayerphysx
aqwerty
aqwerty

Reputation: 61

Collision filtering with layers (PhysX 3.4)

I would like to filter my collisions with layers like in Unity, but I really don't understand how to do it. I'm following this tutorial : http://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/guide/Manual/RigidBodyCollision.html#collision-filtering

All I want to do is disable the collisions between the objects that have the layer Cube and Plane...

Graph.cpp : 

bool Graph::Init()
{
/*...*/

cubeCollider->SetLayer(Physics::PhysicLayer::Cube);
planeCollider->SetLayer(Physics::PhysicLayer::Plane);
sphereCollider->SetLayer(Physics::PhysicLayer::Sphere);
capsuleCollider->SetLayer(Physics::PhysicLayer::Capsule);

_physX->SetCollisionFiltering(Physics::PhysicLayer::Cube, Physics::PhysicLayer::Plane);

/*...*/
}

And here is how I set the filter shader :

PhysX.cpp :

void PhysX::SetCollisionFiltering(PhysicLayer p_one, PhysicLayer p_two)
{
 // I don't really know what to do here...

PxFilterData filterData;

filterData.word0 =  p_one;
filterData.word1 =  p_two;

// no collision between objects with layer ONE and objects with layer TWO ? 
for (unsigned int i = 0; i < _colliders.size(); ++i)
{
    if (_colliders[i]->GetLayer() == p_one || _colliders[i]->GetLayer() == p_two)
        _colliders[i]->GetShape()->setSimulationFilterData(filterData);
}
}

physx::PxFilterFlags CreateFilterShader(PxFilterObjectAttributes p_attributes0, PxFilterData p_filterData0, 
                                    PxFilterObjectAttributes p_attributes1, PxFilterData p_filterData1, 
                                    PxPairFlags& p_pairFlags, const void* p_constantBlock, PxU32 constantBlockSize)

{
    // Trigger
if (PxFilterObjectIsTrigger(p_attributes0) || PxFilterObjectIsTrigger(p_attributes1))
{
    p_pairFlags = PxPairFlag::eDETECT_DISCRETE_CONTACT
        | PxPairFlag::eSOLVE_CONTACT
        | PxPairFlag::eNOTIFY_TOUCH_FOUND
        | PxPairFlag::eNOTIFY_TOUCH_LOST;
}
    // Normal Collision
else
{
            //  Not sure
    if ((p_filterData0.word0 & p_filterData1.word1) && (p_filterData1.word0 & p_filterData0.word1))
    {
        p_pairFlags = PxPairFlag::eDETECT_DISCRETE_CONTACT
            | PxPairFlag::eSOLVE_CONTACT
            | PxPairFlag::eNOTIFY_CONTACT_POINTS
            | PxPairFlag::eNOTIFY_THRESHOLD_FORCE_FOUND
            | PxPairFlag::eNOTIFY_THRESHOLD_FORCE_LOST
            | PxPairFlag::eNOTIFY_THRESHOLD_FORCE_PERSISTS

            | PxPairFlag::eNOTIFY_TOUCH_FOUND
            | PxPairFlag::eNOTIFY_TOUCH_LOST
            | PxPairFlag::eNOTIFY_TOUCH_PERSISTS;
    }
}

return PxFilterFlag::eDEFAULT;
}

With this code, none of my objects collide... I don't really understand what are PxFilter.word0, word1 word2 and word3 by the way...

Thanks in advance !

Upvotes: 2

Views: 878

Answers (1)

Mohammad f
Mohammad f

Reputation: 1061

This a very late answer, just a reference for others.
Based on nvidia documentation you should return eSupress or kill enum. https://docs.nvidia.com/gameworks/content/gameworkslibrary/physx/apireference/files/structPxFilterFlag.html :

    PxFilterFlags PhysicsWorldFilterShader(    
        PxFilterObjectAttributes attributes0, PxFilterData filterData0, 
        PxFilterObjectAttributes attributes1, PxFilterData filterData1,
        PxPairFlags& pairFlags, const void* constantBlock, PxU32 constantBlockSize
    )
    {
        // Checking if layers should be ignored
        auto const layerMaskA = filterData0.word0;
        auto const layerA = filterData0.word1;

        auto const layerMaskB = filterData1.word0;
        auto const layerB = filterData1.word1;

        auto const aCollision = layerMaskA & layerB;
        auto const bCollision = layerMaskB & layerA;
        if (aCollision == 0 || bCollision == 0)
        {
            return PxFilterFlag::eSUPPRESS;
        }

        // all initial and persisting reports for everything, with per-point data
        pairFlags = PxPairFlag::eSOLVE_CONTACT | PxPairFlag::eDETECT_DISCRETE_CONTACT | PxPairFlag::eTRIGGER_DEFAULT;
        return PxFilterFlag::eDEFAULT;
    }

Upvotes: 0

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