update transform serialization to handle migration to uniform scale

Code/Framework/AzCore/AzCore/Math/Aabb.cpp

@@ -227,7 +227,7 @@ namespace AZ
             // the min and max of each part and sum them to get the min and max co-ordinate of the transformed box. For a given new axis,
             // the coefficients for what proportion of each original axis is rotated onto that new axis are the same as the components we
             // would get by performing the inverse rotation on the new axis, so we need to take the conjugate to get the inverse rotation.
-            axisCoeffs = transform.GetScale() * (transform.GetRotation().GetConjugate().TransformVector(axis));
+            axisCoeffs = transform.GetUniformScale() * (transform.GetRotation().GetConjugate().TransformVector(axis));
             a = axisCoeffs * m_min;
             b = axisCoeffs * m_max;
 

Code/Framework/AzCore/AzCore/Math/Obb.cpp

@@ -154,7 +154,7 @@ namespace AZ
         return Obb::CreateFromPositionRotationAndHalfLengths(
             transform.TransformPoint(obb.GetPosition()),
             transform.GetRotation() * obb.GetRotation(),
-            transform.GetScale() * obb.GetHalfLengths()
+            transform.GetUniformScale() * obb.GetHalfLengths()
         );
     }
 }

Code/Framework/AzCore/AzCore/Math/Transform.cpp

@@ -130,8 +130,8 @@ namespace AZ
         const Transform* transform = reinterpret_cast<const Transform*>(classPtr);
         float data[NumFloats];
         transform->GetRotation().StoreToFloat4(data);
-        transform->GetScale().StoreToFloat3(&data[4]);
-        transform->GetTranslation().StoreToFloat3(&data[7]);
+        data[4] = transform->GetUniformScale();
+        transform->GetTranslation().StoreToFloat3(&data[5]);
 
         for (int i = 0; i < NumFloats; i++)
         {
@@ -159,8 +159,8 @@ namespace AZ
 
     size_t TransformSerializer::TextToData(const char* text, unsigned int textVersion, IO::GenericStream& stream, bool isDataBigEndian)
     {
-        const size_t dataBufferSize = AZStd::max(NumFloatsVersion0, NumFloats);
-        const size_t numElements = textVersion < 1 ? NumFloatsVersion0 : NumFloats;
+        const size_t dataBufferSize = AZStd::max(AZStd::max(NumFloatsVersion1, NumFloatsVersion0), NumFloats);
+        const size_t numElements = textVersion < 1 ? NumFloatsVersion0 : (textVersion == 1 ? NumFloatsVersion1 : NumFloats);
 
         size_t nextNumberIndex = 0;
         AZStd::array<float, dataBufferSize> data;
@@ -201,7 +201,34 @@ namespace AZ
             return true;
         }
 
-        // otherwise load as a separate rotation, scale and translation
+        // version 1 had a quaternion rotation, vector3 scale and vector3 translation
+        else if (version == 1)
+        {
+            float data[NumFloatsVersion1];
+            if (stream.GetLength() < sizeof(data))
+            {
+                return false;
+            }
+
+            stream.Read(sizeof(data), reinterpret_cast<void*>(data));
+
+            for (unsigned int i = 0; i < AZ_ARRAY_SIZE(data); ++i)
+            {
+                AZ_SERIALIZE_SWAP_ENDIAN(data[i], isDataBigEndian);
+            }
+
+            Quaternion rotation = Quaternion::CreateFromFloat4(data);
+            Vector3 vectorScale = Vector3::CreateFromFloat3(&data[4]);
+            Vector3 translation = Vector3::CreateFromFloat3(&data[7]);
+
+            float uniformScale = vectorScale.GetMaxElement();
+
+            *reinterpret_cast<Transform*>(classPtr) =
+                Transform::CreateFromQuaternionAndTranslation(rotation, translation) * Transform::CreateUniformScale(uniformScale);
+            return true;
+        }
+
+        // otherwise load as a quaternion rotation, float scale and vector3 translation
         float data[NumFloats];
         if (stream.GetLength() < sizeof(data))
         {
@@ -216,11 +243,11 @@ namespace AZ
         }
 
         Quaternion rotation = Quaternion::CreateFromFloat4(data);
-        Vector3 scale = Vector3::CreateFromFloat3(&data[4]);
-        Vector3 translation = Vector3::CreateFromFloat3(&data[7]);
+        float scale = data[4];
+        Vector3 translation = Vector3::CreateFromFloat3(&data[5]);
 
         *reinterpret_cast<Transform*>(classPtr) =
-            Transform::CreateFromQuaternionAndTranslation(rotation, translation) * Transform::CreateScale(scale);
+            Transform::CreateFromQuaternionAndTranslation(rotation, translation) * Transform::CreateUniformScale(scale);
         return true;
     }
 
@@ -237,7 +264,7 @@ namespace AZ
         if (serializeContext)
         {
             serializeContext->Class<Transform>()
-                ->Version(1)
+                ->Version(2)
                 ->Serializer<TransformSerializer>();
         }
 

Code/Framework/AzCore/AzCore/Math/Transform.h

@@ -25,10 +25,13 @@ namespace AZ
         : public SerializeContext::IDataSerializer
     {
     public:
-        // number of floats in the serialized representation, 4 for rotation, 3 for scale and 3 for translation
-        static constexpr int NumFloats = 10;
+        // number of floats in the serialized representation, 4 for rotation, 1 for scale and 3 for translation
+        static constexpr int NumFloats = 8;
 
-        // number of floats in the old format, which stored a 3x4 matrix
+        // number of floats in version 1, which used 4 for rotation, 3 for scale and 3 for translation
+        static constexpr int NumFloatsVersion1 = 10;
+
+        // number of floats in version 0, which stored a 3x4 matrix
         static constexpr int NumFloatsVersion0 = 12;
 
         size_t Save(const void* classPtr, IO::GenericStream& stream, bool isDataBigEndian) override;

Code/Framework/AzCore/AzCore/Math/TransformSerializer.cpp

@@ -67,7 +67,7 @@ namespace AZ
 
             result.Combine(loadResult);
 
-            transformInstance->SetScale(AZ::Vector3(scale));
+            transformInstance->SetUniformScale(scale);
         }
 
         return context.Report(

Code/Framework/AzCore/Tests/AZTestShared/Math/MathTestHelpers.cpp

@@ -68,7 +68,7 @@ namespace AZ
         return os
             << "translation: " << transform.GetTranslation()
             << " rotation: " << transform.GetRotation()
-            << " scale: " << transform.GetScale();
+            << " scale: " << transform.GetUniformScale();
     }
 
     std::ostream& operator<<(std::ostream& os, const Color& color)