From f335bb8171193d1bff2f297c8c15be49fee0a83b Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Wed, 26 Feb 2014 13:40:09 -0800
Subject: [PATCH] Preserve joint states when switching between LODs.  Closes
 #2077.

---
 interface/src/renderer/FBXReader.cpp |  2 +-
 interface/src/renderer/Model.cpp     | 32 ++++++++++++++++++++++------
 interface/src/renderer/Model.h       |  1 +
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/interface/src/renderer/FBXReader.cpp b/interface/src/renderer/FBXReader.cpp
index 8b881940ca..c9201f8f51 100644
--- a/interface/src/renderer/FBXReader.cpp
+++ b/interface/src/renderer/FBXReader.cpp
@@ -1249,7 +1249,7 @@ FBXGeometry extractFBXGeometry(const FBXNode& node, const QVariantHash& mapping)
         joint.boneRadius = 0.0f;
         joint.inverseBindRotation = joint.inverseDefaultRotation;
         geometry.joints.append(joint);
-        geometry.jointIndices.insert(model.name, geometry.joints.size() - 1);
+        geometry.jointIndices.insert(model.name, geometry.joints.size());
     }
 
     // find our special joints
diff --git a/interface/src/renderer/Model.cpp b/interface/src/renderer/Model.cpp
index e1780ee9f5..7fc16855e7 100644
--- a/interface/src/renderer/Model.cpp
+++ b/interface/src/renderer/Model.cpp
@@ -46,6 +46,17 @@ void Model::initSkinProgram(ProgramObject& program, Model::SkinLocations& locati
     program.release();
 }
 
+QVector<Model::JointState> Model::createJointStates(const FBXGeometry& geometry) {
+    QVector<JointState> jointStates;
+    foreach (const FBXJoint& joint, geometry.joints) {
+        JointState state;
+        state.translation = joint.translation;
+        state.rotation = joint.rotation;
+        jointStates.append(state);
+    }
+    return jointStates;
+}
+
 bool Model::isLoadedWithTextures() const {
     if (!isActive()) {
         return false;
@@ -106,9 +117,23 @@ void Model::reset() {
 
 void Model::simulate(float deltaTime) {
     // update our LOD
+    QVector<JointState> newJointStates;
     if (_geometry) {
         QSharedPointer<NetworkGeometry> geometry = _geometry->getLODOrFallback(_lodDistance, _lodHysteresis);
         if (_geometry != geometry) {
+            if (!_jointStates.isEmpty()) {
+                // copy the existing joint states
+                const FBXGeometry& oldGeometry = _geometry->getFBXGeometry();
+                const FBXGeometry& newGeometry = geometry->getFBXGeometry();
+                newJointStates = createJointStates(newGeometry);
+                for (QHash<QString, int>::const_iterator it = oldGeometry.jointIndices.constBegin();
+                        it != oldGeometry.jointIndices.constEnd(); it++) {
+                    int newIndex = newGeometry.jointIndices.value(it.key());
+                    if (newIndex != 0) {
+                        newJointStates[newIndex - 1] = _jointStates.at(it.value() - 1);
+                    }
+                }
+            }
             deleteGeometry();
             _dilatedTextures.clear();
             _geometry = geometry;
@@ -121,12 +146,7 @@ void Model::simulate(float deltaTime) {
     // set up world vertices on first simulate after load
     const FBXGeometry& geometry = _geometry->getFBXGeometry();
     if (_jointStates.isEmpty()) {
-        foreach (const FBXJoint& joint, geometry.joints) {
-            JointState state;
-            state.translation = joint.translation;
-            state.rotation = joint.rotation;
-            _jointStates.append(state);
-        }
+        _jointStates = newJointStates.isEmpty() ? createJointStates(geometry) : newJointStates;
         foreach (const FBXMesh& mesh, geometry.meshes) {
             MeshState state;
             state.clusterMatrices.resize(mesh.clusters.size());
diff --git a/interface/src/renderer/Model.h b/interface/src/renderer/Model.h
index cf6e1fea6d..fd44361a1b 100644
--- a/interface/src/renderer/Model.h
+++ b/interface/src/renderer/Model.h
@@ -269,6 +269,7 @@ private:
     static SkinLocations _skinNormalMapLocations;
     
     static void initSkinProgram(ProgramObject& program, SkinLocations& locations);
+    static QVector<JointState> createJointStates(const FBXGeometry& geometry);
 };
 
 #endif /* defined(__interface__Model__) */