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  3. FParticlePairMidPhase

FParticlePairMidPhase

Produce collisions for a particle pair A [FParticlePairMidPhase](API\Runtime\Chaos\Chaos\Collision\FParticlePairMidPhase) object is created for every particle pair whose bounds overlap. It is responsible for building a set of potentially colliding shape pairs and running collision detection on those pairs each tick.

API > API/Runtime > API/Runtime/Chaos > API/Runtime/Chaos/Chaos > API/Runtime/Chaos/Chaos/Collision

Inheritance Hierarchy

References

   
Module Chaos
Header /Engine/Source/Runtime/Experimental/Chaos/Public/Chaos/Collision/ParticlePairMidPhase.h
Include #include "Chaos/Collision/ParticlePairMidPhase.h"

Syntax

class FParticlePairMidPhase

Remarks

The lifetime of midphase objects is handled entirely by the CollisionConstraintAllocator. Nothing outside of the CollisionConstraintAllocator should hold a pointer to the detector or any constraints it creates for more than the duration of the tick.

Variables

  Type Name Description
Protected variable FRealSingle CullDistanceScale A number based on the size of the dynamic objects used to scale cull distance.
Protected variable FFlags Flags  
Protected variable FCollisionParticlePairKey Key  
Protected variable int32 LastUsedEpoch  
Protected variable EParticlePairMidPhaseType MidPhaseType VTable Ptr // 8 bytes.
Protected variable int32 NumActiveConstraints  
Protected variable FGeometryParticleHandle * Particle0  
Protected variable FGeometryParticleHandle * Particle1  
Protected variable int32 ParticleCollisionsIndex0 Indices into the arrays of collisions on the particles. This is a cookie for use by FParticleCollisions.
Protected variable int32 ParticleCollisionsIndex1  

Constructors

  Type Name Description
Public function    
Public function    
Public function    

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Protected function void Build the list of potentially colliding shape pairs. This is all the shape pairs in the partilces' shapes arrays that pass the collision filter.
Public function void Prefetch the memory in this class for later use.
Public function Static EParticlePairMidPhaseType  
Public function void Destroy all collisions and prevent this midphasae from being used any more. Called when one of its particles is destoyed. It will be culled at the next Prune in the CollisionConstraintAllocator. We don't delete it immediately so that we don't have to remove it from either Particle's ParticleCollisions array (which is O(N) and unnecessary when the particles are being destroyed)
Public function Virtual FPBDCollisionConstraint *

FindOrCreateConstraint ( FGeometryParticleHandle* InParticle0,
const FImplicitObject* InImplicit0,
const int32 InImplicitId0,
const FShapeInstance* InShape0,
const FBVHParticles* InBVHParticles0,
const FRigidTransform3& InShapeRelativeTransform0,
FGeometryParticleHandle* InParticle1,
const FImplicitObject* Implicit1,
const int32 InImplicitId1,
const FShapeInstance* InShape1,
const FBVHParticles* InBVHParticles1,
const FRigidTransform3& InhapeRelativeTransform1,
const FReal CullDistance,
const EContactShapesType ShapePairType,
const bool bUseManifold,
const bool bEnableSweep,
const FCollisionContext& Context
)

  
Public function void

GenerateCollisions ( const FReal CullDistance,
const FReal Dt,
const FCollisionContext& Context
)

 Create collision constraints for all colliding shape pairs.
Protected function int32

GenerateCollisionsImpl ( const FReal CullDistance,
const FReal Dt,
const FCollisionContext& Context
)

  
Public function Const const FCollisionParticlePairKey &

GetKey ()

  
Public function Const EParticlePairMidPhaseType  
Public function FGeometryParticleHandle *  
Public function FGeometryParticleHandle *  
Public function Const int32 Cookie for use by FParticleCollisions.
Public function void

Init ( FGeometryParticleHandle* InParticle0,
FGeometryParticleHandle* InParticle1,
const FCollisionParticlePairKey& InKey,
const FCollisionContext& Context
)

 Set up the midphase based on the SHapesArrays of the two particles Only intended to be called once right after constructor. We don't do this work in the constructor so that we can reduce the time that the lock is held when allocating new MidPhases.
Protected function void  
Public function void

InjectCollision ( const FPBDCollisionConstraint& Constraint,
const FCollisionContext& Context
)

 Copy a collision and activate it This is used by the Resim system to restore saved colisions. If there is already a matching constraint it will be overwritten, otherwise a new constraint will be added.
Protected function void

InjectCollisionImpl ( const FPBDCollisionConstraint& Constraint,
const FCollisionContext& Context
)

  
Public function Const bool

IsCCD ()

 True if CCD is supported by either particle
Public function Const bool True if CCD is active for this midphase on this frame.This can be changed by modifiers and resets to bIsCCD each frame.
Public function Const bool  
Public function Const bool Whether the particle pair is sleeping and therefore contacts should not be culled (they will be reused on wake)
Public function Const bool

IsUsedSince ( const int32 Epoch
)

 Have we run collision detection since this Epoch (inclusive)
Public function Const bool

IsValid ()

  
Public function Static FParticlePairMidPhase *

Make ( FGeometryParticleHandle* InParticle0,
FGeometryParticleHandle* InParticle1
)

  
Public function void

Reset ()

 Delete all cached data and collisions. Should be called when a particle changes its shapes.
Protected function void  
Public function void  
Public function void

SetCCDIsActive ( bool bCCDIsActive
)

 Override the CCD condition for this mid-phase. Used by the MidPhase modifier and gets reset every frame.
Public function void

SetIsActive ( bool bIsActive
)

 By default midphases are active. If IsActive is set to false, this midphase will not generate a narrow phase.
Public function void

SetIsSleeping ( const bool bInIsSleeping,
const int32 CurrentEpoch
)

 Update the sleeping state If this switches the state to Awake, it will reactivate any collisions between the particle pair that were active when they went to sleep.
Public function void

SetParticleCollisionsIndex ( FGeometryParticleHandle* InParticle,
const int32 InIndex
)

 Cookie for use by FParticleCollisions.
Protected function bool

ShouldEnableCCD ( const FReal Dt
)

 Decide whether we should have CCD enabled on this constraint.
Public function ECollisionVisitorResult

VisitCollisions ( const TLambda& Visitor,
const bool bOnlyActive
)

 Call a lambda on each active collision constraint This includes sleeping constraints, but skips constraints that are were not used on the last awake tick but are still kept around as an optimization.
Public function Const ECollisionVisitorResult

VisitConstCollisions ( const TLambda& Visitor,
const bool bOnlyActive
)

 Call a lambda on each active collision constraint.
Protected function void

WakeCollisionsImpl ( const int32 CurrentEpoch
)

  

Operators

  Type Name Description
Public function FParticlePairMidPhase &  
Public function FParticlePairMidPhase &  

Classes

  Type Name Description
Protected struct FFlags    

See Also

FShapePairParticlePairMidPhase

FGenericParticlePairMidPhase

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