From f918b12b5acfd790caebddec79807bd8eb3332f1 Mon Sep 17 00:00:00 2001
From: Benjamin Jillich <43751992+amzn-jillich@users.noreply.github.com>
Date: Tue, 9 Nov 2021 13:07:20 +0100
Subject: [PATCH] EMotion FX: Taskify dual quat skinning deformer (#5368)

* Moved from job system to task graph for the multi-threaded dual quaternion skinning deformer.
* Prepare the task graph at init time and reuse it at runtime.

Signed-off-by: Benjamin Jillich <jillich@amazon.com>
---
 .../EMotionFX/Source/DualQuatSkinDeformer.cpp | 75 ++++++++++++++-----
 .../EMotionFX/Source/DualQuatSkinDeformer.h   |  3 +
 2 files changed, 58 insertions(+), 20 deletions(-)

diff --git a/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.cpp b/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.cpp
index 2d5d8e2a46..afd570c102 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.cpp
+++ b/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.cpp
@@ -27,6 +27,8 @@ namespace EMotionFX
     DualQuatSkinDeformer::DualQuatSkinDeformer(Mesh* mesh)
         : MeshDeformer(mesh)
     {
+        AZ::TaskGraphActiveInterface* taskGraphActiveInterface = AZ::Interface<AZ::TaskGraphActiveInterface>::Get();
+        m_useTaskGraph = taskGraphActiveInterface && taskGraphActiveInterface->IsTaskGraphActive();
     }
 
     DualQuatSkinDeformer::~DualQuatSkinDeformer()
@@ -79,9 +81,8 @@ namespace EMotionFX
     {
         const Actor* actor = actorInstance->GetActor();
         const Pose* pose = actorInstance->GetTransformData()->GetCurrentPose();
-        const uint32 numVertices = m_mesh->GetNumVertices();
 
-        // pre-calculate the skinning matrices
+        // Calculate the skinning matrices based on the current pose.
         for (BoneInfo& boneInfo : m_bones)
         {
             const size_t nodeIndex = boneInfo.m_nodeNr;
@@ -89,27 +90,38 @@ namespace EMotionFX
             boneInfo.m_dualQuat.FromRotationTranslation(skinTransform.m_rotation, skinTransform.m_position);
         }
 
-        AZ::JobCompletion jobCompletion;
-
-        // Split up the skinned vertices into batches.
-        const AZ::u32 numBatches = aznumeric_caster(ceilf(aznumeric_cast<float>(numVertices) / aznumeric_cast<float>(s_numVerticesPerBatch)));
-        for (AZ::u32 batchIndex = 0; batchIndex < numBatches; ++batchIndex)
+        if (m_useTaskGraph)
         {
-            const AZ::u32 startVertex = batchIndex * s_numVerticesPerBatch;
-            const AZ::u32 endVertex = AZStd::min(startVertex + s_numVerticesPerBatch, numVertices);
-
-            // Create a job for every batch and skin them simultaneously.
-            AZ::JobContext* jobContext = nullptr;
-            AZ::Job* job = AZ::CreateJobFunction([this, startVertex, endVertex]()
-                {
-                    SkinRange(m_mesh, startVertex, endVertex, m_bones);
-                }, /*isAutoDelete=*/true, jobContext);
-
-            job->SetDependent(&jobCompletion);
-            job->Start();
+            // Skin the vertices by executing the task graph.
+            AZ::TaskGraphEvent finishedEvent;
+            m_taskGraph.Submit(&finishedEvent);
+            finishedEvent.Wait();
         }
+        else
+        {
+            AZ::JobCompletion jobCompletion;
 
-        jobCompletion.StartAndWaitForCompletion();
+            // Split up the skinned vertices into batches.
+            const uint32 numVertices = m_mesh->GetNumVertices();
+            const AZ::u32 numBatches = aznumeric_caster(ceilf(aznumeric_cast<float>(numVertices) / aznumeric_cast<float>(s_numVerticesPerBatch)));
+            for (AZ::u32 batchIndex = 0; batchIndex < numBatches; ++batchIndex)
+            {
+                const AZ::u32 startVertex = batchIndex * s_numVerticesPerBatch;
+                const AZ::u32 endVertex = AZStd::min(startVertex + s_numVerticesPerBatch, numVertices);
+
+                // Create a job for every batch and skin them simultaneously.
+                AZ::JobContext* jobContext = nullptr;
+                AZ::Job* job = AZ::CreateJobFunction([this, startVertex, endVertex]()
+                    {
+                        SkinRange(m_mesh, startVertex, endVertex, m_bones);
+                    }, /*isAutoDelete=*/true, jobContext);
+
+                job->SetDependent(&jobCompletion);
+                job->Start();
+            }
+
+            jobCompletion.StartAndWaitForCompletion();
+        }
     }
 
     void DualQuatSkinDeformer::SkinRange(Mesh* mesh, AZ::u32 startVertex, AZ::u32 endVertex, const AZStd::vector<BoneInfo>& boneInfos)
@@ -340,5 +352,28 @@ namespace EMotionFX
                 }
             }
         }
+
+        if (m_useTaskGraph)
+        {
+            // Prepare the task graph
+            // Split up the to be skinned vertices into batches. As the mesh does not change at runtime, the task graph can
+            // be prepared at init time and be reused at runtime.
+            const uint32 numVertices = m_mesh->GetNumVertices();
+            const AZ::u32 numBatches = aznumeric_caster(ceilf(aznumeric_cast<float>(numVertices) / aznumeric_cast<float>(s_numVerticesPerBatch)));
+            for (AZ::u32 batchIndex = 0; batchIndex < numBatches; ++batchIndex)
+            {
+                const AZ::u32 startVertex = batchIndex * s_numVerticesPerBatch;
+                const AZ::u32 endVertex = AZStd::min(startVertex + s_numVerticesPerBatch, numVertices);
+
+                // Create a task for every batch and skin them simultaneously.
+                AZ::TaskDescriptor taskDescriptor{"DualQuatSkinRange", "Animation"};
+                m_taskGraph.AddTask(
+                    taskDescriptor,
+                    [this, startVertex, endVertex]()
+                    {
+                        SkinRange(m_mesh, startVertex, endVertex, m_bones);
+                    });
+            }
+        }
     }
 } // namespace EMotionFX
diff --git a/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.h b/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.h
index 434f2920ee..95312c5b83 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.h
+++ b/Gems/EMotionFX/Code/EMotionFX/Source/DualQuatSkinDeformer.h
@@ -9,6 +9,7 @@
 #pragma once
 
 #include <AzCore/std/containers/vector.h>
+#include <AzCore/Task/TaskGraph.h>
 #include <AzCore/Outcome/Outcome.h>
 #include "EMotionFXConfig.h"
 #include <MCore/Source/DualQuaternion.h>
@@ -138,6 +139,8 @@ namespace EMotionFX
 
         //! Number of vertices per batch/job used for multi-threaded software skinning.
         static constexpr AZ::u32 s_numVerticesPerBatch = 10000;
+        AZ::TaskGraph m_taskGraph;
+        bool m_useTaskGraph = true;
 
         /**
          * Default constructor.