Add replicated physics actor

ReadMe.md

@@ -12,6 +12,7 @@ which makes a bunch of things better:
 * [Debug visualisation](https://www.stevestreeting.com/2021/09/14/ue4-editor-visualisation-helper/)
 * [Better DataTable Row References](https://www.stevestreeting.com/2023/10/06/a-better-unreal-datatable-row-picker/)
 * [Light Flicker](doc/LightFlicker.md)
+* [Replicated Physics Actor](Source/StevesUEHelpers/Public/StevesReplicatedPhysicsActor.h)
 * Halton Sequence based random stream
 
 ## Examples

Source/StevesUEHelpers/Private/StevesReplicatedPhysicsActor.cpp

@@ -0,0 +1,51 @@
+// Copyright Steve Streeting
+// Licensed under the MIT License (see License.txt)
+#include "StevesReplicatedPhysicsActor.h"
+
+
+AStevesReplicatedPhysicsActor::AStevesReplicatedPhysicsActor()
+{
+	PrimaryActorTick.bCanEverTick = false;
+
+	bReplicates = true;
+	bStaticMeshReplicateMovement = true;
+
+	const auto MeshComp = GetStaticMeshComponent();
+	MeshComp->SetMobility(EComponentMobility::Movable);
+	MeshComp->SetCollisionObjectType(ECC_WorldDynamic);
+	MeshComp->bReplicatePhysicsToAutonomousProxy = true;
+
+	// We do NOT replicate MeshComp itself! That's expensive and unnecessary
+
+}
+
+void AStevesReplicatedPhysicsActor::BeginPlay()
+{
+	SetReplicateMovement(true);
+
+	const auto MeshComp = GetStaticMeshComponent();
+
+	// Server test, includes dedicated and listen servers
+	if (IsServer())
+	{
+		// Server collision. Block all but allow pawns through
+		// Subclasses can change this if they like you can change t
+		MeshComp->SetCollisionResponseToAllChannels(ECR_Block);
+		MeshComp->SetCollisionResponseToChannel(ECC_Pawn, ECR_Overlap);
+		MeshComp->SetSimulatePhysics(true);
+	}
+	else
+	{
+		// Ignore all collisions on client
+		MeshComp->SetCollisionResponseToAllChannels(ECR_Ignore);
+	}
+	
+	Super::BeginPlay();	
+}
+
+bool AStevesReplicatedPhysicsActor::IsServer() const
+{
+	// Server test, includes dedicated and listen servers
+	// I prefer this to Authority test because you can't replicate objects client->server or client->client anyway
+	return GetWorld()->GetNetMode() < NM_Client;
+}

Source/StevesUEHelpers/Public/StevesReplicatedPhysicsActor.h

@@ -0,0 +1,23 @@
+// Copyright Steve Streeting
+// Licensed under the MIT License (see License.txt)
+#pragma once
+
+#include "CoreMinimal.h"
+#include "Engine/StaticMeshActor.h"
+#include "StevesReplicatedPhysicsActor.generated.h"
+
+/// A static mesh actor which is simulated on the server and replicated to clients.
+/// The results will be pretty smooth on the clients due to a very specific set of settings.
+/// You MUST spawn this actor ONLY on the server!
+UCLASS(Blueprintable)
+class STEVESUEHELPERS_API AStevesReplicatedPhysicsActor : public AStaticMeshActor
+{
+	GENERATED_BODY()
+
+public:
+	AStevesReplicatedPhysicsActor();
+
+protected:
+	virtual void BeginPlay() override;
+	bool IsServer() const;
+};