apply the hand's velocity to the grabbed actor after release

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+
+- Now, the hand's velocity is applied to grabbed actors after being released from the hand.
+
 ## [1.5.3] - 2023-07-19
 
 This is a hotfix release mostly addressing Android Bluetooth performance issues.

Source/SenseGlove/Private/SenseGlove/GameFramework/SGPawn.cpp

@@ -83,6 +83,14 @@ struct ASGPawn::FImpl
 
     void DisableActorPhysics(const AActor* Actor) const;
     void EnableActorPhysics(const AActor* Actor) const;
+
+    void ApplyHandVelocityToGrabbedActor(const FSGGrabState& GrabState) const;
+
+    void SetGrabbedActor(FSGGrabState& GrabState, AActor* Actor) const;
+    void SetLeftHandGrabbedActor(AActor* Actor) const;
+    void SetRightHandGrabbedActor(AActor* Actor) const;
+
+    void Release(FSGGrabState& GrabState) const;
 };
 
 ASGPawn::ASGPawn(const FObjectInitializer& ObjectInitializer)
@@ -1147,11 +1155,11 @@ void ASGPawn::Grab(USGVirtualHandComponent* Hand, AActor* Actor)
     {
         if (Hand->IsRight())
         {
-            RightHandGrabState.GrabbedActor = Actor;
+            Pimpl->SetRightHandGrabbedActor(Actor);
         }
         else
         {
-            LeftHandGrabState.GrabbedActor = Actor;
+            Pimpl->SetLeftHandGrabbedActor(Actor);
         }
     }
     else
@@ -1169,69 +1177,23 @@ void ASGPawn::Grab(USGVirtualHandComponent* Hand, AActor* Actor)
     Actor->AttachToComponent(Hand, MoveTemp(AttachmentRules), SocketName);
     if (Hand->IsRight())
     {
-        RightHandGrabState.GrabbedActor = Actor;
+        Pimpl->SetRightHandGrabbedActor(Actor);
     }
     else
     {
-        LeftHandGrabState.GrabbedActor = Actor;
+        Pimpl->SetLeftHandGrabbedActor(Actor);
     }
 #endif  /* ENGINE_MAJOR_VERSION >= 5 && ENGINE_MINOR_VERSION >= 2 */
 }
 
 void ASGPawn::ReleaseLeft()
 {
-    if (!IsValid(LeftHandGrabState.GrabbedActor))
+    Pimpl->Release(LeftHandGrabState);
-    {
-        return;
-    }
-
-    const USGGrabComponent* GrabComponent{USGGrabComponent::GetGrabComponent(LeftHandGrabState.GrabbedActor)};
-    if (!IsValid(GrabComponent))
-    {
-        return;
-    }
-
-    LeftHandGrabState.GrabbedActor->DetachFromActor(
-        FDetachmentTransformRules(GrabComponent->GetDetachmentLocationRule(),
-                                  GrabComponent->GetDetachmentRotationRule(),
-                                  GrabComponent->GetDetachmentScaleRule(),
-                                  GrabComponent->GetDetachmentInCallModify())
-        );
-
-    if (GrabComponent->GetAffectPhysicsState())
-    {
-        Pimpl->EnableActorPhysics(LeftHandGrabState.GrabbedActor);
-    }
-
-    LeftHandGrabState.GrabbedActor = nullptr;
 }
 
 void ASGPawn::ReleaseRight()
 {
-    if (!IsValid(RightHandGrabState.GrabbedActor))
+    Pimpl->Release(RightHandGrabState);
-    {
-        return;
-    }
-
-    const USGGrabComponent* GrabComponent{USGGrabComponent::GetGrabComponent(RightHandGrabState.GrabbedActor)};
-    if (!IsValid(GrabComponent))
-    {
-        return;
-    }
-
-    RightHandGrabState.GrabbedActor->DetachFromActor(
-        FDetachmentTransformRules(GrabComponent->GetDetachmentLocationRule(),
-                                  GrabComponent->GetDetachmentRotationRule(),
-                                  GrabComponent->GetDetachmentScaleRule(),
-                                  GrabComponent->GetDetachmentInCallModify())
-        );
-
-    if (GrabComponent->GetAffectPhysicsState())
-    {
-        Pimpl->EnableActorPhysics(RightHandGrabState.GrabbedActor);
-    }
-
-    RightHandGrabState.GrabbedActor = nullptr;
 }
 
 ASGPawn::FImpl::FImpl(ASGPawn* InOwner)
@@ -1429,7 +1391,6 @@ void ASGPawn::FImpl::UnbindFingerTouchOverlapEvents()
 void ASGPawn::FImpl::DisableActorPhysics(const AActor* Actor) const
 {
     UPrimitiveComponent* ActorRootComponent{Cast<UPrimitiveComponent>(Actor->GetRootComponent())};
-
     if (!ensureAlwaysMsgf(IsValid(ActorRootComponent), TEXT("RootComponent is not a valid UPrimativeComponent!")))
     {
         return;
@@ -1437,6 +1398,7 @@ void ASGPawn::FImpl::DisableActorPhysics(const AActor* Actor) const
 
     ActorRootComponent->SetEnableGravity(false);
     ActorRootComponent->SetSimulatePhysics(false);
+    ActorRootComponent->PutRigidBodyToSleep();
 }
 
 void ASGPawn::FImpl::EnableActorPhysics(const AActor* Actor) const
@@ -1447,7 +1409,6 @@ void ASGPawn::FImpl::EnableActorPhysics(const AActor* Actor) const
     }
 
     UPrimitiveComponent* ActorRootComponent{Cast<UPrimitiveComponent>(Actor->GetRootComponent())};
-
     if (!ensureAlwaysMsgf(IsValid(ActorRootComponent), TEXT("RootComponent is not a valid UPrimativeComponent!")))
     {
         return;
@@ -1455,6 +1416,80 @@ void ASGPawn::FImpl::EnableActorPhysics(const AActor* Actor) const
 
     ActorRootComponent->SetEnableGravity(true);
     ActorRootComponent->SetSimulatePhysics(true);
+    ActorRootComponent->WakeRigidBody();
+}
+
+void ASGPawn::FImpl::ApplyHandVelocityToGrabbedActor(const FSGGrabState& GrabState) const
+{
+    if (!IsValid(GrabState.Hand))
+    {
+        return;
+    }
+
+    if (!IsValid(GrabState.GrabbedActor))
+    {
+        return;
+    }
+
+    UPrimitiveComponent* ActorRootComponent{Cast<UPrimitiveComponent>(GrabState.GrabbedActor->GetRootComponent())};
+    if (!ensureAlwaysMsgf(IsValid(ActorRootComponent), TEXT("RootComponent is not a valid UPrimativeComponent!")))
+    {
+        return;
+    }
+
+    /// NOTE: this produces almost the same values
+    // FVector ActorVelocity{
+    //    (GrabState.GrabbedActor->GetActorLocation() - GrabState.PreviousLocation) / DeltaSeconds
+    // };
+    FVector ActorVelocity{GrabState.GrabbedActor->GetVelocity()};
+
+    ActorRootComponent->SetPhysicsLinearVelocity(ActorVelocity);
+    ActorRootComponent->AddImpulse(MoveTemp(ActorVelocity), NAME_None, true);
+}
+
+void ASGPawn::FImpl::SetGrabbedActor(FSGGrabState& GrabState, AActor* Actor) const
+{
+    GrabState.GrabbedActor = Actor;
+}
+
+void ASGPawn::FImpl::SetLeftHandGrabbedActor(AActor* Actor) const
+{
+    SetGrabbedActor(Owner->LeftHandGrabState, Actor);
+}
+
+void ASGPawn::FImpl::SetRightHandGrabbedActor(AActor* Actor) const
+{
+    SetGrabbedActor(Owner->RightHandGrabState, Actor);
+}
+
+void ASGPawn::FImpl::Release(FSGGrabState& GrabState) const
+{
+    if (!IsValid(GrabState.GrabbedActor))
+    {
+        return;
+    }
+
+    const USGGrabComponent* GrabComponent{USGGrabComponent::GetGrabComponent(GrabState.GrabbedActor)};
+    if (!IsValid(GrabComponent))
+    {
+        return;
+    }
+
+    GrabState.GrabbedActor->DetachFromActor(
+        FDetachmentTransformRules(GrabComponent->GetDetachmentLocationRule(),
+                                  GrabComponent->GetDetachmentRotationRule(),
+                                  GrabComponent->GetDetachmentScaleRule(),
+                                  GrabComponent->GetDetachmentInCallModify())
+        );
+
+    if (GrabComponent->GetAffectPhysicsState())
+    {
+        EnableActorPhysics(GrabState.GrabbedActor);
+    }
+
+    ApplyHandVelocityToGrabbedActor(GrabState);
+
+    SetGrabbedActor(GrabState, nullptr);
 }
 
 ASGPawn::FImpl::~FImpl() = default;