VoxelForge/Source/VoxelForgeLivingPlane/Public/VoxelForgeLivingPlaneActor.h

#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;
};