From bdab3fa3216a5c4ee5385c7131604bfd40fb143a Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Sun, 28 Sep 2014 18:02:57 +0200
Subject: [PATCH] Bullet optimization: Don't update AABBs of static objects
 every frame

---
 apps/openmw/mwworld/physicssystem.cpp | 18 +++++++++++++++---
 libs/openengine/bullet/physic.cpp     |  7 +++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/apps/openmw/mwworld/physicssystem.cpp b/apps/openmw/mwworld/physicssystem.cpp
index d5267b8cf..97ea7ca91 100644
--- a/apps/openmw/mwworld/physicssystem.cpp
+++ b/apps/openmw/mwworld/physicssystem.cpp
@@ -40,7 +40,7 @@ using namespace Ogre;
 namespace
 {
 
-void animateCollisionShapes (std::map<OEngine::Physic::RigidBody*, OEngine::Physic::AnimatedShapeInstance>& map)
+void animateCollisionShapes (std::map<OEngine::Physic::RigidBody*, OEngine::Physic::AnimatedShapeInstance>& map, btDynamicsWorld* dynamicsWorld)
 {
     for (std::map<OEngine::Physic::RigidBody*, OEngine::Physic::AnimatedShapeInstance>::iterator it = map.begin();
          it != map.end(); ++it)
@@ -79,6 +79,9 @@ void animateCollisionShapes (std::map<OEngine::Physic::RigidBody*, OEngine::Phys
             compound->getChildShape(shapeIt->second)->setLocalScaling(BtOgre::Convert::toBullet(bone->_getDerivedScale()));
             compound->updateChildTransform(shapeIt->second, trans);
         }
+
+        // needed because we used btDynamicsWorld::setForceUpdateAllAabbs(false)
+        dynamicsWorld->updateSingleAabb(it->first);
     }
 }
 
@@ -670,11 +673,18 @@ namespace MWWorld
         const Ogre::Vector3 &position = node->getPosition();
 
         if(OEngine::Physic::RigidBody *body = mEngine->getRigidBody(handle))
+        {
             body->getWorldTransform().setOrigin(btVector3(position.x,position.y,position.z));
+            mEngine->mDynamicsWorld->updateSingleAabb(body);
+        }
 
         if(OEngine::Physic::RigidBody *body = mEngine->getRigidBody(handle, true))
+        {
             body->getWorldTransform().setOrigin(btVector3(position.x,position.y,position.z));
+            mEngine->mDynamicsWorld->updateSingleAabb(body);
+        }
 
+        // Actors update their AABBs every frame (DISABLE_DEACTIVATION), so no need to do it manually
         if(OEngine::Physic::PhysicActor *physact = mEngine->getCharacter(handle))
             physact->setPosition(position);
     }
@@ -696,6 +706,7 @@ namespace MWWorld
                 body->getWorldTransform().setRotation(btQuaternion(rotation.x, rotation.y, rotation.z, rotation.w));
             else
                 mEngine->boxAdjustExternal(handleToMesh[handle], body, node->getScale().x, node->getPosition(), rotation);
+            mEngine->mDynamicsWorld->updateSingleAabb(body);
         }
         if (OEngine::Physic::RigidBody* body = mEngine->getRigidBody(handle, true))
         {
@@ -703,6 +714,7 @@ namespace MWWorld
                 body->getWorldTransform().setRotation(btQuaternion(rotation.x, rotation.y, rotation.z, rotation.w));
             else
                 mEngine->boxAdjustExternal(handleToMesh[handle], body, node->getScale().x, node->getPosition(), rotation);
+            mEngine->mDynamicsWorld->updateSingleAabb(body);
         }
     }
 
@@ -864,8 +876,8 @@ namespace MWWorld
 
     void PhysicsSystem::stepSimulation(float dt)
     {
-        animateCollisionShapes(mEngine->mAnimatedShapes);
-        animateCollisionShapes(mEngine->mAnimatedRaycastingShapes);
+        animateCollisionShapes(mEngine->mAnimatedShapes, mEngine->mDynamicsWorld);
+        animateCollisionShapes(mEngine->mAnimatedRaycastingShapes, mEngine->mDynamicsWorld);
 
         mEngine->stepSimulation(dt);
     }
diff --git a/libs/openengine/bullet/physic.cpp b/libs/openengine/bullet/physic.cpp
index f2be11386..d3aa714f1 100644
--- a/libs/openengine/bullet/physic.cpp
+++ b/libs/openengine/bullet/physic.cpp
@@ -97,6 +97,8 @@ namespace Physic
                 (0,0, mShape.get());
         mBody = new RigidBody(CI, name);
         mBody->mPlaceable = false;
+        mBody->setCollisionFlags(btCollisionObject::CF_KINEMATIC_OBJECT);
+        mBody->setActivationState(DISABLE_DEACTIVATION);
 
         setPosition(position);
         setRotation(rotation);
@@ -233,6 +235,11 @@ namespace Physic
 
         // The world.
         mDynamicsWorld = new btDiscreteDynamicsWorld(dispatcher,broadphase,solver,collisionConfiguration);
+
+        // Don't update AABBs of all objects every frame. Most objects in MW are static, so we don't need this.
+        // Should a "static" object ever be moved, we have to update its AABB manually using DynamicsWorld::updateSingleAabb.
+        mDynamicsWorld->setForceUpdateAllAabbs(false);
+
         mDynamicsWorld->setGravity(btVector3(0,0,-10));
 
         if(BulletShapeManager::getSingletonPtr() == NULL)