From 66a030b800c0def8a0b15847b3661b990f925837 Mon Sep 17 00:00:00 2001
From: amzn-mike <80125227+amzn-mike@users.noreply.github.com>
Date: Wed, 9 Jun 2021 22:35:03 -0500
Subject: [PATCH] Fix transform data

Use first offsetMatrix for a bone (there may be multiple) and calculate using offsetOfParent * inverseRootOffset * rootOffset * inverseOffset

(cherry picked from commit a8eae976dda39ad28f9aa235e1e6ba34715ac48a)

# Conflicts:
#	Code/Tools/SceneAPI/FbxSceneBuilder/Importers/AssImpTransformImporter.cpp
---
 .../Importers/AssImpTransformImporter.cpp     | 39 ++++++++++++++-----
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/Code/Tools/SceneAPI/FbxSceneBuilder/Importers/AssImpTransformImporter.cpp b/Code/Tools/SceneAPI/FbxSceneBuilder/Importers/AssImpTransformImporter.cpp
index 153dfce69d..dc59f59147 100644
--- a/Code/Tools/SceneAPI/FbxSceneBuilder/Importers/AssImpTransformImporter.cpp
+++ b/Code/Tools/SceneAPI/FbxSceneBuilder/Importers/AssImpTransformImporter.cpp
@@ -46,8 +46,9 @@ namespace AZ
                     serializeContext->Class<AssImpTransformImporter, SceneCore::LoadingComponent>()->Version(1);
                 }
             }
-
-            void GetAllBones(const aiScene* scene, AZStd::unordered_map<AZStd::string, const aiBone*>& boneLookup)
+            
+            void GetAllBones(
+                const aiScene* scene, AZStd::unordered_multimap<AZStd::string, const aiBone*>& boneLookup)
             {
                 for (unsigned meshIndex = 0; meshIndex < scene->mNumMeshes; ++meshIndex)
                 {
@@ -57,7 +58,7 @@ namespace AZ
                     {
                         const aiBone* bone = mesh->mBones[boneIndex];
 
-                        boneLookup[bone->mName.C_Str()] = bone;
+                        boneLookup.emplace(bone->mName.C_Str(), bone);
                     }
                 }
             }
@@ -73,18 +74,19 @@ namespace AZ
                     return Events::ProcessingResult::Ignored;
                 }
 
-                AZStd::unordered_map<AZStd::string, const aiBone*> boneLookup;
+                AZStd::unordered_multimap<AZStd::string, const aiBone*> boneLookup;
                 GetAllBones(scene, boneLookup);
 
                 auto boneIterator = boneLookup.find(currentNode->mName.C_Str());
                 const bool isBone = boneIterator != boneLookup.end();
 
-                if (currentNode->mName.C_Str() == AZStd::string("FrontCloth_02"))
+                if (currentNode->mName.C_Str() == AZStd::string("spine_C0_0_jnt"))
                 {
-                    __debugbreak();
+                    //__debugbreak();
                 }
 
                 aiMatrix4x4 combinedTransform;
+                DataTypes::MatrixType finalMat;
 
                 if (isBone)
                 {
@@ -121,7 +123,16 @@ namespace AZ
                     while (curNode && boneLookup.count(curNode->mName.C_Str()))
                     {
                         AZStd::string name = curNode->mName.C_Str();
-                        addOffset(name, boneLookup.at(name)->mOffsetMatrix);
+
+                        auto range = boneLookup.equal_range(name);
+
+                        for (auto it = range.first; it != range.second; ++it)
+                        {
+                            addOffset(name, it->second->mOffsetMatrix);
+                            break;
+                        }
+
+                        //addOffset(name, boneLookup.at(name)->mOffsetMatrix);
                         addTransform(name, curNode->mTransformation);
 
                         curNode = curNode->mParent;
@@ -152,14 +163,24 @@ namespace AZ
                     //combinedTransform = parentOffset * inverseOffset;
 
                     //parentTransform ^-1 * parentParent * azOffsetInverse
-                    combinedTransform = parentTransformInverse * rootOffsetMatrix * inverseOffset;
+                    //combinedTransform = parentTransformInverse * rootOffsetMatrix * inverseOffset;
+
+                    //azNodeLocal = offsets[1] * inverseOffsets[3] * (offsets[3] * inverseOffsets[0])
+                    finalMat =
+                        offsets.at(AZ::GetMin(offsets.size()-1, (decltype(offsets.size()))1)) * inverseOffsets.at(inverseOffsets.size() - 1) * offsets.at(offsets.size() - 1) * inverseOffsets.at(0);
                 }
                 else
                 {
                     combinedTransform = GetConcatenatedLocalTransform(currentNode);
                 }
 
-                DataTypes::MatrixType localTransform = AssImpSDKWrapper::AssImpTypeConverter::ToTransform(combinedTransform);
+                //DataTypes::MatrixType localTransform = AssImpSDKWrapper::AssImpTypeConverter::ToTransform(combinedTransform);
+                DataTypes::MatrixType localTransform = finalMat;
+
+                if (localTransform == DataTypes::MatrixType::Identity())
+                {
+                    return Events::ProcessingResult::Ignored;
+                }
 
                 context.m_sourceSceneSystem.SwapTransformForUpAxis(localTransform);
                 context.m_sourceSceneSystem.ConvertUnit(localTransform);