That piece of code and surroundings must be like:
RHISetRenderTarget(TextureRenderTarget->GetRenderTargetTexture(), NULL); // was the Clear, replaced like
// Be sure we're blending right without any alpha influence on Color blending
///////////////////////////////////////////////////////////////////////
// pre 4.17: RHICmdList.SetBlendState(TStaticBlendState<>::GetRHI());
TShaderMapRef<FQuadVS> QuadVS(GetGlobalShaderMap(GMaxRHIFeatureLevel));
TShaderMapRef<FUpdateDisplacementPS> UpdateDisplacementPS(GetGlobalShaderMap(GMaxRHIFeatureLevel));
FGraphicsPipelineStateInitializer GraphicsPSOInit;
RHICmdList.ApplyCachedRenderTargets(GraphicsPSOInit);
GraphicsPSOInit.DepthStencilState = TStaticDepthStencilState<false, CF_Always>::GetRHI();
GraphicsPSOInit.BlendState = TStaticBlendState<>::GetRHI();
GraphicsPSOInit.RasterizerState = TStaticRasterizerState<>::GetRHI();
GraphicsPSOInit.PrimitiveType = PT_TriangleList;
GraphicsPSOInit.BoundShaderState.VertexDeclarationRHI = GQuadVertexDeclaration.VertexDeclarationRHI;
GraphicsPSOInit.BoundShaderState.VertexShaderRHI = GETSAFERHISHADER_VERTEX(*QuadVS);
GraphicsPSOInit.BoundShaderState.PixelShaderRHI = GETSAFERHISHADER_PIXEL(*UpdateDisplacementPS);
SetGraphicsPipelineState(RHICmdList, GraphicsPSOInit);
// pre 4.17: static FGlobalBoundShaderState UpdateDisplacementBoundShaderState;
// pre 4.17: SetGlobalBoundShaderState(RHICmdList, GMaxRHIFeatureLevel, UpdateDisplacementBoundShaderState, GQuadVertexDeclaration.VertexDeclarationRHI, *QuadVS, *UpdateDisplacementPS);
///////////////////////////////////////////////////////////////////////
Now there is an with the ENQUEUE_UNIQUE_RENDER_COMMAND_THREEPARAMETER, but Im going to look at it tomorrow, Im tired.