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  3. FNiagaraGPUInstanceCountManager

FNiagaraGPUInstanceCountManager

A manager that handles the buffer containing the GPU particle count.

API > API/Plugins > API/Plugins/Niagara

References

   
Module Niagara
Header /Engine/Plugins/FX/Niagara/Source/Niagara/Classes/NiagaraGPUInstanceCountManager.h
Include #include "NiagaraGPUInstanceCountManager.h"

Syntax

class FNiagaraGPUInstanceCountManager

Remarks

A manager that handles the buffer containing the GPU particle count. Also provides related functionalities like the generation of the draw indirect buffer.

Variables

  Type Name Description
Protected variable int32 AllocatedCulledCounts The allocated instance counts in the culled count buffer
Protected variable int32 AllocatedInstanceCounts The allocated instance counts in CountBuffer
Protected variable bool bAcquiredCulledCounts Whether or not the culled counts were acquired this frame
Protected variable FRWBuffer CountBuffer A buffer holding the each emitter particle count after a simulation tick.
Protected variable FRHIGPUMemoryReadback * CountReadback  
Protected variable int32 CountReadbackSize  
Protected variable FRWBuffer CulledCountBuffer  
Protected variable ERHIAccess CulledCountsRHIAccess Used to track RHI access for the culled counts buffer.
Protected variable TArray< FNiagaraDrawIndirectArgGenTaskInfo >[ENiagaraGPUCountUpdatePhase::Max] DrawIndirectArgGenTasks The list of all draw indirected tasks that are to be run in UpdateDrawIndirectBuffers()
Protected variable TMap< FNiagaraDrawIndirectArgGenTaskInfo, FNiagaraDrawIndirectArgGenSlotInfo > DrawIndirectArgMap  
Protected variable uint32 DrawIndirectLowWaterFrames  
Protected variable TArray< FIndirectArgsPoolEntryPtr > DrawIndirectPool Buffers holding drawindirect data to render GPU emitter renderers.
Protected variable ERHIFeatureLevel::Type FeatureLevel  
Protected variable TArray< uint32 > FreeEntries  
Protected variable TArray< uint32 > InstanceCountClearTasks The list of all instance count clear tasks that are to be run in UpdateDrawIndirectBuffers()
Protected variable int32 MultiViewAllocatedInstanceCounts Mirrored copy of CountBuffer for multi-view rendering.
Protected variable FRWBuffer MultiViewCountBuffer  
Protected variable int32 RequiredCulledCounts The number of culled instance counts needed from view culling
Protected variable int32 UsedInstanceCounts The current used instance counts allocated from FNiagaraDataBuffer::AllocateGPU()

Constructors

  Type Name Description
Public function    

Destructors

  Type Name Description
Public function    

Functions

  Type Name Description
Public function FRWBuffer *  
Public function uint32  
Public function uint32 Acquire an entry from the free list, assumes this comes from being presized.
Public function uint32 Acquire an entry, this will either come from the free list or reallocate the buffer.
Public function FIndirectArgSlot

AddDrawIndirect ( FRHICommandListBase& RHICmdList,
uint32 InstanceCountBufferOffset,
uint32 NumIndicesPerInstance,
uint32 StartIndexLocation,
bool bIsInstancedStereoEnabled,
bool bCulled,
ENiagaraGpuComputeTickStage::Type ReadyTickStage
)

 Add a draw indirect task to generate the draw indirect args.
Public function Const bool  
Public function void  
Public function void  
Public function void  
Public function void

FreeEntry ( uint32& BufferOffset
)

 Free the entry and reset it to INDEX_NONE if valid.
Public function void

FreeEntryArray ( TConstArrayView< uint32 > EntryArray
)

 Free and array of entries, you are expected to reset or change to INDEX_NONE.
Public function const uint32 *  
Public function Const const FRWBuffer &  
Public function Const bool  
Public function Const bool  
Public function void

InitRHI ( FRHICommandListBase& RHICmdList
)

 Init resource for the first time.
Protected function void  
Public function void  
Public function void Free resources.
Public function void

ResizeBuffers ( FRHICommandListImmediate& RHICmdList,
int32 ReservedInstanceCounts
)

 Resize instance count and draw indirect buffers to ensure it is big enough to hold all draw indirect args.
Public function void Generate the draw indirect buffers, and reset all release counts.

Classes

  Type Name Description
Public struct FIndirectArgSlot    
Protected struct FIndirectArgsPoolEntry    
Protected struct FNiagaraDrawIndirectArgGenSlotInfo Set to allow de-duplication of FNiagaraDrawIndirectArgGenTaskInfo.  

Typedefs

Name Description
FIndirectArgsPoolEntryPtr  

Constants

Name Description
kCountBufferDefaultState  
kIndirectArgsDefaultState  

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