From 36dc2dc49d3bad4c8f3b9613d63b3fdc72ef4eb2 Mon Sep 17 00:00:00 2001
From: Atlante45 <clement.brisset@gmail.com>
Date: Sun, 26 Feb 2017 10:18:37 -0800
Subject: [PATCH] Compute spine length on skeleton load

---
 libraries/animation/src/AnimInverseKinematics.cpp | 12 ++++++++++++
 libraries/animation/src/AnimInverseKinematics.h   |  1 +
 2 files changed, 13 insertions(+)

diff --git a/libraries/animation/src/AnimInverseKinematics.cpp b/libraries/animation/src/AnimInverseKinematics.cpp
index c22819f22d..65de35ce5f 100644
--- a/libraries/animation/src/AnimInverseKinematics.cpp
+++ b/libraries/animation/src/AnimInverseKinematics.cpp
@@ -938,10 +938,22 @@ void AnimInverseKinematics::setSkeletonInternal(AnimSkeleton::ConstPointer skele
         } else {
             _hipsParentIndex = -1;
         }
+
+        auto currentJointIndex = _headIndex;
+        auto parentJointIndex = _skeleton->getParentIndex(currentJointIndex);
+        _spineLength = 0.0f;
+        while (currentJointIndex != _hipsIndex && parentJointIndex != -1) {
+            _spineLength += glm::distance(_skeleton->getAbsoluteDefaultPose(currentJointIndex).trans(),
+                                          _skeleton->getAbsoluteDefaultPose(parentJointIndex).trans());
+
+            currentJointIndex = parentJointIndex;
+            parentJointIndex = _skeleton->getParentIndex(currentJointIndex);
+        }
     } else {
         clearConstraints();
         _headIndex = -1;
         _hipsIndex = -1;
         _hipsParentIndex = -1;
+        _spineLength = 0.0f;
     }
 }
diff --git a/libraries/animation/src/AnimInverseKinematics.h b/libraries/animation/src/AnimInverseKinematics.h
index 892a5616b2..ad5018b0b8 100644
--- a/libraries/animation/src/AnimInverseKinematics.h
+++ b/libraries/animation/src/AnimInverseKinematics.h
@@ -91,6 +91,7 @@ protected:
     int _headIndex { -1 };
     int _hipsIndex { -1 };
     int _hipsParentIndex { -1 };
+    float _spineLength { 0.0f };
 
     // _maxTargetIndex is tracked to help optimize the recalculation of absolute poses
     // during the the cyclic coordinate descent algorithm