From 4f2eaf1adb11255a98178e751a9ae8257c0ed13b Mon Sep 17 00:00:00 2001
From: H0zen <H0zen@users.noreply.github.com>
Date: Sun, 18 Dec 2016 16:32:36 +0200
Subject: [PATCH] Remove rotation matrices from GameObjectModel

  - the quaternions are more numerically stable and faster than matrices
---
 src/game/ChatCommands/Level2.cpp  |  2 +-
 src/game/vmap/GameObjectModel.cpp | 14 +++++---------
 src/game/vmap/GameObjectModel.h   | 13 ++++---------
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/src/game/ChatCommands/Level2.cpp b/src/game/ChatCommands/Level2.cpp
index abf5f745..3f5dc498 100644
--- a/src/game/ChatCommands/Level2.cpp
+++ b/src/game/ChatCommands/Level2.cpp
@@ -58,7 +58,7 @@
 #include <map>
 #include <typeinfo>
 #include "Formulas.h"
-#include "G3D/Quat.h"                                         // for turning GO's
+#include "G3D/Quat.h"                                       // for turning GO's
 #include "TargetedMovementGenerator.h"                      // for HandleNpcUnFollowCommand
 #include "MoveMap.h"                                        // for mmap manager
 #include "PathFinder.h"                                     // for mmap commands
diff --git a/src/game/vmap/GameObjectModel.cpp b/src/game/vmap/GameObjectModel.cpp
index 00757a1c..78d1f76a 100644
--- a/src/game/vmap/GameObjectModel.cpp
+++ b/src/game/vmap/GameObjectModel.cpp
@@ -32,7 +32,6 @@
 #include "GameObjectModel.h"
 #include "DBCStores.h"
 #include "Creature.h"
-#include "G3D/Quat.h"
 
 struct GameobjectModelData
 {
@@ -136,9 +135,7 @@ bool GameObjectModel::initialize(const GameObject* const pGo, const GameObjectDi
 
 void GameObjectModel::UpdateRotation(G3D::Quat const& q)
 {
-    q.toRotationMatrix(iRot);
-
-    iInvRot = iRot.inverse();
+    iQuat = q;
 
     G3D::AABox mdl_box(iModelBound);
 
@@ -148,7 +145,7 @@ void GameObjectModel::UpdateRotation(G3D::Quat const& q)
     G3D::AABox rotated_bounds;
 
     for (int i = 0; i < 8; ++i)
-        { rotated_bounds.merge(iRot * mdl_box.corner(i)); }
+        { rotated_bounds.merge((iQuat * G3D::Quat(mdl_box.corner(i)) * iQuat.conj()).imag()); }
 
     iBound = rotated_bounds + iPos;
 }
@@ -179,8 +176,8 @@ bool GameObjectModel::IntersectRay(const G3D::Ray& ray, float& MaxDist, bool Sto
         { return false; }
 
     // child bounds are defined in object space:
-    Vector3 p = iInvRot * (ray.origin() - iPos) * iInvScale;
-    Ray modRay(p, iInvRot * ray.direction());
+    Vector3 p = (iQuat.conj() * G3D::Quat((ray.origin() - iPos) * iInvScale) * iQuat).imag();
+    Ray modRay(p, (iQuat.conj() * G3D::Quat(ray.direction()) * iQuat).imag());
     float distance = MaxDist * iInvScale;
     bool hit = iModel->IntersectRay(modRay, distance, StopAtFirstHit);
     if (hit)
@@ -195,7 +192,7 @@ bool GameObjectModel::GetIntersectPoint(const G3D::Vector3& srcPoint, G3D::Vecto
 {
     G3D::Vector3 p;
     if (absolute)
-        p = iInvRot * (srcPoint - iPos) * iInvScale;
+        p = (iQuat * G3D::Quat((srcPoint - iPos) * iInvScale) * iQuat.conj()).imag();
     else
         p = srcPoint;
 
@@ -218,4 +215,3 @@ void GameObjectModel::GetWorldCoords(const G3D::Vector3& localCoords, G3D::Vecto
 {
 
 }
-
diff --git a/src/game/vmap/GameObjectModel.h b/src/game/vmap/GameObjectModel.h
index 492cbc85..738e90b8 100644
--- a/src/game/vmap/GameObjectModel.h
+++ b/src/game/vmap/GameObjectModel.h
@@ -31,6 +31,7 @@
 #include <G3D/Vector3.h>
 #include <G3D/AABox.h>
 #include <G3D/Ray.h>
+#include <G3D/Quat.h>
 #include "DBCStructure.h"
 #include "GameObject.h"
 
@@ -40,11 +41,6 @@ namespace VMAP
     class WorldModel;
 }
 
-namespace G3D
-{
-    class Quat;
-}
-
 /**
  * @brief
  *
@@ -52,17 +48,16 @@ namespace G3D
 class GameObjectModel
 {
     private:
-        bool         isCollidable;
+        bool          isCollidable;
 
         std::string   iName;
         G3D::AABox    iBound;
         G3D::AABox    iModelBound;
         G3D::Vector3  iPos;
-        G3D::Matrix3  iRot;
-        float         iScale;
+        G3D::Quat     iQuat;  //Note: this must be a unit quaternion!!!
 
+        float         iScale;
         float         iInvScale;
-        G3D::Matrix3  iInvRot;
 
         VMAP::WorldModel* iModel;
         GameObject const* iOwner;