experiment: LivingPlane repeatable + standalone UE runtime module (L164)

Readback barrier fix (GL_TEXTURE_UPDATE_BARRIER_BIT before glGetTexImage); check_repeatability.py compares full-field
checksums across query/capture settings - Intel GPU PASS (3b9d45905c7aafff), llvmpipe PASS, mismatch control fails.
New runtime module VoxelForgeLivingPlane (separate from generation): RDG global shader (Shaders/LivingPlane.usf),
ping-pong RGBA32F render targets, actor with WPO plane and object inputs, no CPU readback. Compiles in Linux UE 5.7.
Windows build: Source/VoxelForgeLivingPlane/*, Shaders/LivingPlane.usf, VoxelForge.uplugin. Setup: UE-SETUP.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016dhxM43dnWvUu2B5Ph1iG1

Source/VoxelForgeLivingPlane/Public/VoxelForgeLivingPlaneActor.h

@@ -0,0 +1,114 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "GameFramework/Actor.h"
+#include "VoxelForgeLivingPlaneActor.generated.h"
+
+class UMaterialInterface;
+class UMaterialInstanceDynamic;
+class UStaticMeshComponent;
+class UTextureRenderTarget2D;
+
+USTRUCT(BlueprintType)
+struct FVFLivingPlaneObjectInput
+{
+	GENERATED_BODY()
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Object")
+	FVector WorldPositionCm = FVector(0.0, 0.0, 43.0);
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Object")
+	FVector WorldVelocityCmPerSecond = FVector::ZeroVector;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Object", meta=(ClampMin="0.1"))
+	float RadiusCm = 43.0f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Object", meta=(ClampMin="0.0"))
+	float PushAccelerationMetersPerSecondSquared = 36.0f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Object")
+	bool bActive = false;
+};
+
+/** A render-only, GPU-stepped heightfield plane. Object state is uploaded; the field is never read back. */
+UCLASS(BlueprintType, Blueprintable)
+class VOXELFORGELIVINGPLANE_API AVoxelForgeLivingPlaneActor : public AActor
+{
+	GENERATED_BODY()
+
+public:
+	AVoxelForgeLivingPlaneActor();
+
+	virtual void BeginPlay() override;
+	virtual void Tick(float DeltaSeconds) override;
+	virtual void OnConstruction(const FTransform& Transform) override;
+	virtual void EndPlay(const EEndPlayReason::Type EndPlayReason) override;
+
+	UFUNCTION(BlueprintCallable, Category="Living Plane|Object")
+	void SetObjectState(int32 ObjectIndex, const FVFLivingPlaneObjectInput& State);
+
+	UFUNCTION(BlueprintCallable, Category="Living Plane")
+	void ResetSimulation();
+
+	UFUNCTION(BlueprintPure, Category="Living Plane")
+	int64 GetSimulationStepCount() const { return SimulationStepCount; }
+
+	UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category="Living Plane")
+	TObjectPtr<UStaticMeshComponent> PlaneMesh;
+
+	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category="Living Plane|Rendering")
+	TObjectPtr<UMaterialInterface> PlaneMaterial;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation", meta=(ClampMin="16", ClampMax="2048"))
+	int32 GridSize = 256;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation", meta=(ClampMin="1.0", ClampMax="100.0"))
+	float PlaneLengthMeters = 12.0f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation", meta=(ClampMin="0.0"))
+	float WaveSpeedMetersPerSecond = 4.5f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation", meta=(ClampMin="0.0"))
+	float DampingPerSecond = 1.35f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation", meta=(ClampMin="0.0"))
+	float FoundationStiffnessPerSecondSquared = 28.0f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation")
+	bool bEnableBreathing = true;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Simulation", meta=(ClampMin="0.0", ClampMax="30.0"))
+	float BreathingStrengthMetersPerSecondSquared = 4.8f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Imprint")
+	bool bEnableImprint = true;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Imprint", meta=(ClampMin="0.0", ClampMax="1.0"))
+	float ImprintCaptureMetersPerSecond = 0.15f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Imprint", meta=(ClampMin="0.1", ClampMax="60.0"))
+	float ImprintRecoverySeconds = 6.0f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Imprint", meta=(ClampMin="0.0", ClampMax="1.0"))
+	float ImprintMaxDepthMeters = 0.34f;
+
+	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category="Living Plane|Object")
+	TArray<FVFLivingPlaneObjectInput> ObjectInputs;
+
+private:
+	void CreateFieldTargets();
+	void EnqueueSimulationSteps(int32 NumSteps);
+	void UpdateMaterialField();
+	float GetStableStepSeconds() const;
+
+	UPROPERTY(Transient)
+	TObjectPtr<UTextureRenderTarget2D> FieldTargets[2];
+
+	UPROPERTY(Transient)
+	TObjectPtr<UMaterialInstanceDynamic> DynamicPlaneMaterial;
+
+	int32 CurrentFieldIndex = 0;
+	int64 SimulationStepCount = 0;
+	double SimulationAccumulatorSeconds = 0.0;
+	double FixedStepSeconds = 0.0;
+};