ParticleSystemSceneProxy.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Materials/MaterialRelevance.h"
#include "Particles/ParticlePerfStats.h"
#include "PrimitiveSceneProxy.h"
#include "PrimitiveSceneProxyDesc.h"
 
class FColoredMaterialRenderProxy;
class FParticleDynamicData;
class UParticleSystemComponent;
struct FDynamicEmitterDataBase;
 
 
struct FParticleSystemSceneProxyDesc : public FPrimitiveSceneProxyDesc
{
    ENGINE_API FParticleSystemSceneProxyDesc();
    ENGINE_API FParticleSystemSceneProxyDesc(UParticleSystemComponent& Component, FParticleDynamicData* InDynamicData, bool InbCanBeOccluded);
 
    UParticleSystem* SystemAsset;
    FParticleDynamicData* DynamicData;
    FMaterialRelevance MaterialRelevance;
    int32 VisualizeLODIndex; // Only used in the LODColoration view mode.
    int32 LODMethod;
    uint8 bCanBeOccluded : 1;
    uint8 bManagingSignificance : 1;
    uint8 bAlwaysHasVelocity : 1;
 
    ENGINE_API virtual void GetUsedMaterials(TArray<UMaterialInterface*>& OutMaterials, bool bGetDebugMaterials = false) const override;
};
 
 
class FParticleSystemSceneProxy final : public FPrimitiveSceneProxy
{
public:
    SIZE_T GetTypeHash() const override;
 
    ENGINE_API FParticleSystemSceneProxy(const FParticleSystemSceneProxyDesc& Desc);
    virtual ~FParticleSystemSceneProxy();
 
    // FPrimitiveSceneProxy interface.
    virtual bool CanBeOccluded() const override
    {
        return  bCanBeOccluded ? !MaterialRelevance.bDisableDepthTest : false;
    }
 
    virtual bool HasCustomOcclusionBounds() const override
    {
        return bCanBeOccluded ? bHasCustomOcclusionBounds : FPrimitiveSceneProxy::HasCustomOcclusionBounds();
    }
 
    virtual FBoxSphereBounds GetCustomOcclusionBounds() const override
    {
        return bCanBeOccluded ? OcclusionBounds.TransformBy(GetLocalToWorld()) : FPrimitiveSceneProxy::GetCustomOcclusionBounds();
    }
 
    virtual void GetDynamicMeshElements(const TArray<const FSceneView*>& Views, const FSceneViewFamily& ViewFamily, uint32 VisibilityMap, FMeshElementCollector& Collector) const override;
    virtual FPrimitiveViewRelevance GetViewRelevance(const FSceneView* View) const override;
    virtual void OnTransformChanged(FRHICommandListBase& RHICmdList) override;
 
    virtual void GatherSimpleLights(const FSceneViewFamily& ViewFamily, FSimpleLightArray& OutParticleLights) const override;
 
    virtual void CreateRenderThreadResources(FRHICommandListBase& RHICmdList) override;
 
    void ReleaseRenderThreadResources();
 
    ENGINE_API void UpdateData(FParticleDynamicData* NewDynamicData);
    void UpdateData_RenderThread(FParticleDynamicData* NewDynamicData);
 
    FParticleDynamicData* GetDynamicData()
    {
        return DynamicData;
    }
 
    FParticleDynamicData* GetLastDynamicData()
    {
        return LastDynamicData;
    }
 
    void SetLastDynamicData(FParticleDynamicData* InLastDynamicData)
    {
        LastDynamicData  = InLastDynamicData;
    }
 
    virtual uint32 GetMemoryFootprint( void ) const override { return( sizeof( *this ) + GetAllocatedSize() ); }
    uint32 GetAllocatedSize( void ) const 
    { 
        uint32 AdditionalSize = (uint32)FPrimitiveSceneProxy::GetAllocatedSize();
 
        return( AdditionalSize ); 
    }
 
    // @param FrameNumber from ViewFamily.FrameNumber
    void DetermineLODDistance(const FSceneView* View, int32 FrameNumber);
 
    void UpdateWorldSpacePrimitiveUniformBuffer(FRHICommandListBase& RHICmdList) const;
 
    void GetObjectPositionAndScale(const FSceneView& View, FVector2D& ObjectNDCPosition, FVector2D& ObjectMacroUVScales) const;
 
    // While this isn't good OO design, access to everything is made public.
    // This is to allow custom emitter instances to easily be written when extending the engine.
    FMatrix GetWorldToLocal() const     {   return GetLocalToWorld().Inverse(); }
    bool GetCastShadow() const          {   return bCastShadow;             }
    const FMaterialRelevance& GetMaterialRelevance() const
    {
        return MaterialRelevance;
    }
    float GetPendingLODDistance() const {   return PendingLODDistance;      }
    void SetVisualizeLODIndex(int32 InVisualizeLODIndex) { VisualizeLODIndex = InVisualizeLODIndex; }
    int32  GetVisualizeLODIndex() const { return VisualizeLODIndex; }
 
    inline FRHIUniformBuffer* GetWorldSpacePrimitiveUniformBuffer() const { return WorldSpacePrimitiveUniformBuffer.GetUniformBufferRHI(); }
 
    const FColoredMaterialRenderProxy* GetDeselectedWireframeMatInst() const { return DeselectedWireframeMaterialInstance; }
 
    FMeshBatch* GetPooledMeshBatch();
 
    // persistent proxy storage for mesh emitter LODs; need to store these here, because GDME needs to calc the index,
    // but VF needs to be init'ed with the correct LOD, and DynamicData goes away every frame
    mutable TArray<int32> MeshEmitterLODIndices;
    ERHIFeatureLevel::Type GetFeatureLevel() const { return FeatureLevel;  }
protected:
 
    void CreateRenderThreadResourcesForEmitterData();
 
    void ReleaseRenderThreadResourcesForEmitterData();
 
#if STATS
    double LastStatCaptureTime;
    uint8 bCountedThisFrame:1;
#endif
 
    uint8 bCastShadow : 1;
    uint8 bManagingSignificance : 1;
 
private:
    uint8   bCanBeOccluded : 1;
    uint8   bHasCustomOcclusionBounds : 1;
 
protected:
    TEnumAsByte<ERHIFeatureLevel::Type> FeatureLevel;
 
    FMaterialRelevance MaterialRelevance;
 
    FParticleDynamicData* DynamicData;          // RENDER THREAD USAGE ONLY
    FParticleDynamicData* LastDynamicData;      // RENDER THREAD USAGE ONLY
 
    FColoredMaterialRenderProxy* DeselectedWireframeMaterialInstance;
 
    int32 LODMethod;
    float PendingLODDistance;
    int32 VisualizeLODIndex; // Only used in the LODColoration view mode.
 
    // from ViewFamily.FrameNumber
    int32 LastFramePreRendered;
 
    mutable TUniformBuffer<FPrimitiveUniformShaderParameters> WorldSpacePrimitiveUniformBuffer;
    mutable uint32 WorldSpaceUBHash = 0;
    mutable UE::FMutex WorldSpacePrimitiveUniformBufferMutex;
 
    TIndirectArray<FMeshBatch, TInlineAllocator<4> > MeshBatchPool;
    int32 FirstFreeMeshBatch;
 
private:
    FBoxSphereBounds OcclusionBounds;
 
protected:
    mutable TArray<FDynamicEmitterDataBase*> DynamicDataForThisFrame;
 
    friend struct FDynamicSpriteEmitterDataBase;
 
#if WITH_PARTICLE_PERF_STATS
public:
    FParticlePerfStatsContext PerfStatContext;
#endif
};