bullet: Sync with current upstream master branch

This updates our local copy to commit 5ec8339b6fc491e3f09a34a4516e82787f053fcc.
We need a recent master commit for some new features that we use in Godot
(see #25543 and #28909).

To avoid warnings generated by Bullet headers included in our own module,
we include those headers with -isystem on GCC and Clang.

Fixes #29503.

3 files changed, 21 insertions, 6 deletions

diff --git a/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.cpp b/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.cpp
index 98a02d0c45..b48d9301d7 100644
--- a/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.cpp
+++ b/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.cpp
@@ -43,6 +43,7 @@ btCollisionObject::btCollisionObject()
 	  m_userObjectPointer(0),
 	  m_userIndex2(-1),
 	  m_userIndex(-1),
+	  m_userIndex3(-1),
 	  m_hitFraction(btScalar(1.)),
 	  m_ccdSweptSphereRadius(btScalar(0.)),
 	  m_ccdMotionThreshold(btScalar(0.)),
diff --git a/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.h b/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.h
index 56b3d89e56..85dc488c8c 100644
--- a/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.h
+++ b/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionObject.h
@@ -101,6 +101,8 @@ protected:
 
 	int m_userIndex;
 
+	int m_userIndex3;
+
 	///time of impact calculation
 	btScalar m_hitFraction;
 
@@ -526,6 +528,11 @@ public:
 		return m_userIndex2;
 	}
 
+	int getUserIndex3() const
+	{
+		return m_userIndex3;
+	}
+
 	///users can point to their objects, userPointer is not used by Bullet
 	void setUserPointer(void* userPointer)
 	{
@@ -543,6 +550,11 @@ public:
 		m_userIndex2 = index;
 	}
 
+	void setUserIndex3(int index)
+	{
+		m_userIndex3 = index;
+	}
+
 	int getUpdateRevisionInternal() const
 	{
 		return m_updateRevision;
diff --git a/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionWorld.cpp b/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
index b30ce03164..71184f36ac 100644
--- a/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
+++ b/thirdparty/bullet/BulletCollision/CollisionDispatch/btCollisionWorld.cpp
@@ -19,10 +19,10 @@ subject to the following restrictions:
 #include "BulletCollision/CollisionShapes/btCollisionShape.h"
 #include "BulletCollision/CollisionShapes/btConvexShape.h"
 #include "BulletCollision/NarrowPhaseCollision/btGjkEpaPenetrationDepthSolver.h"
-#include "BulletCollision/CollisionShapes/btSphereShape.h" //for raycasting
-#include "BulletCollision/CollisionShapes/btBvhTriangleMeshShape.h" //for raycasting
-#include "BulletCollision/CollisionShapes/btScaledBvhTriangleMeshShape.h" //for raycasting
-#include "BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h" //for raycasting
+#include "BulletCollision/CollisionShapes/btSphereShape.h"                 //for raycasting
+#include "BulletCollision/CollisionShapes/btBvhTriangleMeshShape.h"        //for raycasting
+#include "BulletCollision/CollisionShapes/btScaledBvhTriangleMeshShape.h"  //for raycasting
+#include "BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h"     //for raycasting
 #include "BulletCollision/NarrowPhaseCollision/btRaycastCallback.h"
 #include "BulletCollision/CollisionShapes/btCompoundShape.h"
 #include "BulletCollision/NarrowPhaseCollision/btSubSimplexConvexCast.h"
@@ -414,7 +414,9 @@ void btCollisionWorld::rayTestSingleInternal(const btTransform& rayFromTrans, co
 				rcb.m_hitFraction = resultCallback.m_closestHitFraction;
 				triangleMesh->performRaycast(&rcb, rayFromLocalScaled, rayToLocalScaled);
 			}
-			else if (collisionShape->getShapeType()==TERRAIN_SHAPE_PROXYTYPE)
+			else if (((resultCallback.m_flags&btTriangleRaycastCallback::kF_DisableHeightfieldAccelerator)==0) 
+				&& collisionShape->getShapeType() == TERRAIN_SHAPE_PROXYTYPE 
+				)
 			{
 				///optimized version for btHeightfieldTerrainShape
 				btHeightfieldTerrainShape* heightField = (btHeightfieldTerrainShape*)collisionShape;
@@ -422,7 +424,7 @@ void btCollisionWorld::rayTestSingleInternal(const btTransform& rayFromTrans, co
 				btVector3 rayFromLocal = worldTocollisionObject * rayFromTrans.getOrigin();
 				btVector3 rayToLocal = worldTocollisionObject * rayToTrans.getOrigin();
 
-				BridgeTriangleRaycastCallback rcb(rayFromLocal,rayToLocal,&resultCallback,collisionObjectWrap->getCollisionObject(),heightField,colObjWorldTransform);
+				BridgeTriangleRaycastCallback rcb(rayFromLocal, rayToLocal, &resultCallback, collisionObjectWrap->getCollisionObject(), heightField, colObjWorldTransform);
 				rcb.m_hitFraction = resultCallback.m_closestHitFraction;
 				heightField->performRaycast(&rcb, rayFromLocal, rayToLocal);
 			}