From 386dad7aff4357abfe39cd32bfbb1c9bd52e5b04 Mon Sep 17 00:00:00 2001
From: "Anthony J. Thibault" <tony@highfidelity.io>
Date: Tue, 24 Nov 2015 18:57:35 -0800
Subject: [PATCH] Fixes hand IK for some avatars

Specifically:

   https://hifi-content.s3.amazonaws.com/ozan/dev/avatars/hifi_team/ryan/_test/ryan.fst
   https://hifi-content.s3.amazonaws.com/ozan/dev/avatars/hifi_team/brad/brad.fst
   https://s3.amazonaws.com/hifi-public/tony/blackmery/blackmery.fst

These avatars have "Hips" joints that are NOT the root of the skeleton.
This would cause the getRootAbsoluteBindPoseByChildName() to return (0,0,0).
Causing the IK targets to be lower then they should have.
---
 libraries/animation/src/AnimSkeleton.cpp | 17 -----------------
 libraries/animation/src/AnimSkeleton.h   |  1 -
 libraries/animation/src/Rig.cpp          | 10 +++++-----
 3 files changed, 5 insertions(+), 23 deletions(-)

diff --git a/libraries/animation/src/AnimSkeleton.cpp b/libraries/animation/src/AnimSkeleton.cpp
index 7ec8db1490..b87d649e31 100644
--- a/libraries/animation/src/AnimSkeleton.cpp
+++ b/libraries/animation/src/AnimSkeleton.cpp
@@ -49,23 +49,6 @@ const AnimPose& AnimSkeleton::getAbsoluteBindPose(int jointIndex) const {
     return _absoluteBindPoses[jointIndex];
 }
 
-AnimPose AnimSkeleton::getRootAbsoluteBindPoseByChildName(const QString& childName) const {
-    AnimPose pose = AnimPose::identity;
-    int jointIndex = nameToJointIndex(childName);
-    if (jointIndex >= 0) {
-        int numJoints = (int)(_absoluteBindPoses.size());
-        if (jointIndex < numJoints) {
-            int parentIndex = getParentIndex(jointIndex);
-            while (parentIndex != -1 && parentIndex < numJoints) {
-                jointIndex = parentIndex;
-                parentIndex = getParentIndex(jointIndex);
-            }
-            pose = _absoluteBindPoses[jointIndex];
-        }
-    }
-    return pose;
-}
-
 const AnimPose& AnimSkeleton::getRelativeBindPose(int jointIndex) const {
     return _relativeBindPoses[jointIndex];
 }
diff --git a/libraries/animation/src/AnimSkeleton.h b/libraries/animation/src/AnimSkeleton.h
index 9dda313528..98e2b5882f 100644
--- a/libraries/animation/src/AnimSkeleton.h
+++ b/libraries/animation/src/AnimSkeleton.h
@@ -31,7 +31,6 @@ public:
 
     // absolute pose, not relative to parent
     const AnimPose& getAbsoluteBindPose(int jointIndex) const;
-    AnimPose getRootAbsoluteBindPoseByChildName(const QString& childName) const;
 
     // relative to parent pose
     const AnimPose& getRelativeBindPose(int jointIndex) const;
diff --git a/libraries/animation/src/Rig.cpp b/libraries/animation/src/Rig.cpp
index 046603d660..029fd20e44 100644
--- a/libraries/animation/src/Rig.cpp
+++ b/libraries/animation/src/Rig.cpp
@@ -1306,10 +1306,10 @@ void Rig::updateFromHandParameters(const HandParameters& params, float dt) {
 
         // TODO: figure out how to obtain the yFlip from where it is actually stored
         glm::quat yFlipHACK = glm::angleAxis(PI, glm::vec3(0.0f, 1.0f, 0.0f));
-        AnimPose rootBindPose = _animSkeleton->getRootAbsoluteBindPoseByChildName("LeftHand");
+        AnimPose hipsBindPose = _animSkeleton->getAbsoluteBindPose(_animSkeleton->nameToJointIndex("Hips"));
         if (params.isLeftEnabled) {
-            _animVars.set("leftHandPosition", rootBindPose.trans + rootBindPose.rot * yFlipHACK * params.leftPosition);
-            _animVars.set("leftHandRotation", rootBindPose.rot * yFlipHACK * params.leftOrientation);
+            _animVars.set("leftHandPosition", hipsBindPose.trans + hipsBindPose.rot * yFlipHACK * params.leftPosition);
+            _animVars.set("leftHandRotation", hipsBindPose.rot * yFlipHACK * params.leftOrientation);
             _animVars.set("leftHandType", (int)IKTarget::Type::RotationAndPosition);
         } else {
             _animVars.unset("leftHandPosition");
@@ -1317,8 +1317,8 @@ void Rig::updateFromHandParameters(const HandParameters& params, float dt) {
             _animVars.set("leftHandType", (int)IKTarget::Type::HipsRelativeRotationAndPosition);
         }
         if (params.isRightEnabled) {
-            _animVars.set("rightHandPosition", rootBindPose.trans + rootBindPose.rot * yFlipHACK * params.rightPosition);
-            _animVars.set("rightHandRotation", rootBindPose.rot * yFlipHACK * params.rightOrientation);
+            _animVars.set("rightHandPosition", hipsBindPose.trans + hipsBindPose.rot * yFlipHACK * params.rightPosition);
+            _animVars.set("rightHandRotation", hipsBindPose.rot * yFlipHACK * params.rightOrientation);
             _animVars.set("rightHandType", (int)IKTarget::Type::RotationAndPosition);
         } else {
             _animVars.unset("rightHandPosition");