Hair - fixing per object UI control per object (#4507)

- Deferred material array index was not passed every frame (the objects' material array is built during the frame)

Signed-off-by: Adi-Amazon <barlev@amazon.com>

Gems/AtomTressFX/Code/Rendering/HairFeatureProcessor.cpp

@@ -226,27 +226,34 @@ namespace AZ
 
                 // Prepare materials array for the per pass srg
                 std::vector<const AMD::TressFXRenderParams*> hairObjectsRenderMaterials;
-                uint32_t obj = 0;
-                for (auto objIter = m_hairRenderObjects.begin(); objIter != m_hairRenderObjects.end(); ++objIter, ++obj)
+                uint32_t objectIndex = 0;
+                for (auto& renderObject : m_hairRenderObjects)
                 {
-                    HairRenderObject* renderObject = objIter->get();
                     if (!renderObject->IsEnabled())
                     {
                         continue;
                     }
-                    renderObject->Update();
+
+                    renderObject->SetRenderIndex(objectIndex);
 
                     // [To Do] Hair - update the following parameters for dynamic LOD control
                     // should change or when parameters are being changed on the editor side.
 //                         float Distance = sqrtf( m_activeScene.scene->GetCameraPos().x * m_activeScene.scene->GetCameraPos().x +
 //                                                  m_activeScene.scene->GetCameraPos().y * m_activeScene.scene->GetCameraPos().y +
 //                                                  m_activeScene.scene->GetCameraPos().z * m_activeScene.scene->GetCameraPos().z);
-//                    objIter->get()->UpdateRenderingParameters(
-//                              renderingSettings, m_nScreenWidth * m_nScreenHeight * AVE_FRAGS_PER_PIXEL, m_deltaTime, Distance);
+                    const float distanceFromCamera = 1.0f;      // fixed distance until LOD mechanism is worked on
+                    const float updateShadows = false;          // same here - currently cheap self shadow approx
+                    renderObject->UpdateRenderingParameters( nullptr, RESERVED_PIXELS_FOR_OIT, distanceFromCamera, updateShadows);
 
-                    // this will be used for the constant buffer
+                    // this will be used in the constant buffer to set the material array used by the resolve pass
                     hairObjectsRenderMaterials.push_back(renderObject->GetHairRenderParams());
+
+                    // The data update for the GPU bind - this should be the very last thing done after the
+                    // data has been read and / or altered on the CPU side.
+                    renderObject->Update();
+                    ++objectIndex;
                 }
+
                 FillHairMaterialsArray(hairObjectsRenderMaterials);
             }
 
@@ -532,4 +539,3 @@ namespace AZ
         } // namespace Hair
     } // namespace Render
 } // namespace AZ
-

Gems/AtomTressFX/Code/Rendering/HairRenderObject.cpp

@@ -878,6 +878,11 @@ namespace AZ
                 const AMD::TressFXRenderingSettings* parameters, const int nodePoolSize,
                 float distance, bool shadowUpdate /*= false*/)
             {
+                if (!parameters)
+                {
+                    parameters = m_renderSettings;
+                }
+
                 // Update Render Parameters
                 // If you alter FiberRadius make sure to change it also in the material properties
                 // passed by the Feature Processor for the shading. 
@@ -888,7 +893,7 @@ namespace AZ
 
                 // original TressFX lighting parameters - two specular lobes approximating
                 // the Marschner R and and TRT lobes + diffuse component. 
-                m_renderCB->MatKValue = {{{0.f, parameters->m_HairKDiffuse, parameters->m_HairKSpec1, parameters->m_HairSpecExp1}}};
+                m_renderCB->MatKValue = { {{0.f, parameters->m_HairKDiffuse, parameters->m_HairKSpec1, parameters->m_HairSpecExp1}} };
                 m_renderCB->HairKs2 = parameters->m_HairKSpec2;
                 m_renderCB->HairEx2 = parameters->m_HairSpecExp2;
 
@@ -903,11 +908,13 @@ namespace AZ
                 m_strandCB->TipPercentage = parameters->m_TipPercentage;
                 m_strandCB->StrandUVTilingFactor = parameters->m_StrandUVTilingFactor;
                 m_strandCB->FiberRatio = parameters->m_FiberRatio;
+                m_strandCB->EnableThinTip = parameters->m_EnableThinTip;
+                m_strandCB->EnableStrandUV = parameters->m_EnableStrandUV;
 
                 // Reset LOD hair density for the frame
                 m_LODHairDensity = 1.f;
+                float fiberRadius = parameters->m_FiberRadius;
 
-                float FiberRadius = parameters->m_FiberRadius;
                 if (parameters->m_EnableHairLOD)
                 {
                     float MinLODDist = shadowUpdate ?
@@ -922,23 +929,18 @@ namespace AZ
                         float DistanceRatio = AZStd::min((distance - MinLODDist) / AZStd::max(MaxLODDist - MinLODDist, 0.00001f), 1.f);
 
                         // Lerp: x + s(y-x)
-                        float MaxLODFiberRadius = FiberRadius * (shadowUpdate ? parameters->m_ShadowLODWidthMultiplier : parameters->m_LODWidthMultiplier);
-                        FiberRadius = FiberRadius + (DistanceRatio * (MaxLODFiberRadius - FiberRadius));
+                        float MaxLODFiberRadius = fiberRadius * (shadowUpdate ? parameters->m_ShadowLODWidthMultiplier : parameters->m_LODWidthMultiplier);
+                        fiberRadius = fiberRadius + (DistanceRatio * (MaxLODFiberRadius - fiberRadius));
 
                         // Lerp: x + s(y-x)
                         m_LODHairDensity = 1.f + (DistanceRatio * ((shadowUpdate ? parameters->m_ShadowLODPercent : parameters->m_LODPercent) - 1.f));
                     }
                 }
 
-                m_strandCB->FiberRadius = FiberRadius;
-
-                m_strandCB->NumVerticesPerStrand = m_NumVerticesPerStrand;  // Always constant
-                m_strandCB->EnableThinTip = parameters->m_EnableThinTip;
+                m_strandCB->FiberRadius = fiberRadius;
+                m_strandCB->NumVerticesPerStrand = m_NumVerticesPerStrand;  // Constant through the run per object
                 m_strandCB->NodePoolSize = nodePoolSize;
-                m_strandCB->RenderParamsIndex = m_RenderIndex;              // Always constant
-
-                m_strandCB->EnableStrandUV = parameters->m_EnableStrandUV;
-                m_strandCB->EnableStrandTangent = parameters->m_EnableStrandTangent;
+                m_strandCB->RenderParamsIndex = m_RenderIndex;      // Per Objects specific according to its index in the FP
             }
 
             //!=====================================================================================
@@ -977,8 +979,10 @@ namespace AZ
                 UpdateSimulationParameters(simSettings, SIMULATION_TIME_STEP); 
 
                 // [To Do] Hair - change to be dynamically calculated
-                const float distanceFromCamera = 1.0; 
+                const float distanceFromCamera = 1.0f; 
                 const float updateShadows = false;
+                m_renderSettings = renderSettings;
+                m_simSettings = simSettings;
                 UpdateRenderingParameters(renderSettings, RESERVED_PIXELS_FOR_OIT, distanceFromCamera, updateShadows);
 
                 if (!GetShaders())

Gems/AtomTressFX/Code/Rendering/HairRenderObject.h

@@ -269,6 +269,7 @@ namespace AZ
                 void UpdateSimulationParameters(const AMD::TressFXSimulationSettings* settings, float timeStep);
 
                 void SetWind(const Vector3& windDir, float windMag, int frame);
+                void SetRenderIndex(uint32_t renderIndex) { m_RenderIndex = renderIndex; }
 
                 void ResetPositions() { m_simCB->g_ResetPositions = 1.0f; }
                 void IncreaseSimulationFrame()
@@ -315,6 +316,10 @@ namespace AZ
 
                 float m_frameDeltaTime = 0.02;
 
+                //! The following are the configuration settings that might be required during the update.
+                AMD::TressFXSimulationSettings* m_simSettings = nullptr;
+                AMD::TressFXRenderingSettings* m_renderSettings = nullptr;
+
                 //! Hair asset information
                 uint32_t m_TotalIndices = 0;
                 uint32_t m_NumTotalVertices = 0;
@@ -331,7 +336,7 @@ namespace AZ
 
                 //! Controls reset / copy base hair state
                 uint32_t m_SimulationFrame = 0;
-                // [To Do] - verify if still required
+                //! The index used as a look up into the material array during the resolve pass
                 uint32_t m_RenderIndex = 0;
 
                 //!-----------------------------------------------------------------