From 0603fee04e29b6c09c7bf632b38a074f38f6c308 Mon Sep 17 00:00:00 2001
From: Benjamin Jillich <43751992+amzn-jillich@users.noreply.github.com>
Date: Thu, 29 Apr 2021 12:20:20 +0200
Subject: [PATCH] [LYN-3072] TQO Animation: "Retarget Motion" on Simple Motion
 sends Asserts (#358)

* Added a check to only apply retargeting to animated joints. Joints that the motion does not animate won't have a valid motion data link and thus retargeting can't be applied.
* The check cannot be applied at a level above as we still need to adjust the translation for root nodes, even for the ones that the motion does not animate.
---
 .../Source/MotionData/MotionData.cpp          | 30 +++++++++++--------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/Gems/EMotionFX/Code/EMotionFX/Source/MotionData/MotionData.cpp b/Gems/EMotionFX/Code/EMotionFX/Source/MotionData/MotionData.cpp
index 834f4f6ef4..8c5083e8e9 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Source/MotionData/MotionData.cpp
+++ b/Gems/EMotionFX/Code/EMotionFX/Source/MotionData/MotionData.cpp
@@ -461,16 +461,17 @@ namespace EMotionFX
     {
         AZ_Assert(motionLinkData, "Expecting valid motionLinkData pointer.");
 
+        const Pose* bindPose = actorInstance->GetTransformData()->GetBindPose();
+        const AZStd::vector<AZ::u32>& jointLinks = motionLinkData->GetJointDataLinks();
+
         // Special case handling on translation of root nodes.
         // Scale the translation amount based on the height difference between the bind pose height of the
         // retarget root node and the bind pose of that node stored in the motion.
         // All other nodes get their translation data displaced based on the position difference between the
         // parent relative space positions in the actor instance's bind pose and the motion bind pose.
-        const Pose* bindPose = actorInstance->GetTransformData()->GetBindPose();
         const Actor* actor = actorInstance->GetActor();
         const AZ::u32 retargetRootIndex = actor->GetRetargetRootNodeIndex();
         const Node* joint = actor->GetSkeleton()->GetNode(jointIndex);
-        const AZStd::vector<AZ::u32>& jointLinks = motionLinkData->GetJointDataLinks();
         bool needsDisplacement = true;
         if ((retargetRootIndex == jointIndex || joint->GetIsRootNode()) && retargetRootIndex != InvalidIndex32)
         {
@@ -487,20 +488,23 @@ namespace EMotionFX
             }
         }
 
-        const Transform& bindPoseTransform = bindPose->GetLocalSpaceTransform(jointIndex);
         const AZ::u16 jointDataIndex = jointLinks[jointIndex];
-        const Transform& motionBindPose = m_staticJointData[jointDataIndex].m_bindTransform;
-        if (needsDisplacement)
+        if (jointDataIndex != InvalidIndex16)
         {
-            const AZ::Vector3 displacement = bindPoseTransform.mPosition - motionBindPose.mPosition;
-            inOutTransform.mPosition += displacement;
-        }
+            const Transform& bindPoseTransform = bindPose->GetLocalSpaceTransform(jointIndex);
+            const Transform& motionBindPose = m_staticJointData[jointDataIndex].m_bindTransform;
+            if (needsDisplacement)
+            {
+                const AZ::Vector3 displacement = bindPoseTransform.mPosition - motionBindPose.mPosition;
+                inOutTransform.mPosition += displacement;
+            }
 
-        EMFX_SCALECODE
-        (
-            const AZ::Vector3 scaleOffset = bindPoseTransform.mScale - motionBindPose.mScale;
-            inOutTransform.mScale += scaleOffset;
-        )
+            EMFX_SCALECODE
+            (
+                const AZ::Vector3 scaleOffset = bindPoseTransform.mScale - motionBindPose.mScale;
+                inOutTransform.mScale += scaleOffset;
+            )
+        }
     }
 
     // Based on a given time value, find the two keyframes to interpolate between, and calculate the t value, which is the interpolation weight between 0 and 1.