Gpu particles perfomance

Development Asset Creation FX
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1

I ran into this problem when the camera is very close to the Particle Emitter FPS falls somewhere with very stable 60 to 15.
the effect is a …

41055-emiter.jpg
41055-emiter.jpg1000×622 102 KB

material for effect

41057-material.png
41057-material.png1000×578 143 KB

material parameter distance set from code only once if dist value changed

TArray<FString> Instances;
	UMaterialInstanceDynamic* MI = nullptr;
	Instances.Empty();
	FString Path = "MaterialInstanceConstant'/Game/BillBoards/fogMaterial_Inst.fogMaterial_Inst'";
	MI = (UMaterialInstanceDynamic*)LoadObject<UMaterialInstance>(NULL, *Path);
	if (MI)
	{
		MI->Modify();
		MI->SetScalarParameterValue("distance", dist);
	}
2

Is this your tick function? If it is, then this looks really bogus.

You are loading a material instance every tick, which is already as slow as it gets. However you are also using the UMaterialInstance as UMaterialInstanceDynamic which is not correct. Try the CastChecked() instead of a plain c-style cast to make sure you can safely cast between the two types. So basically you are modifying the source asset (MaterialInstance) and not a dynamic instance of that material.

Instead you should create a dynamic material instance during initialization (e.g. BeginPlay), keep the pointer to it and then only set the distance parameter within your tick function.

Marc

3

partly yes, this function is called in the game 1 - 2 times.