From a077f8f493266aac00ce119e5f20ae81c1dc80ed Mon Sep 17 00:00:00 2001
From: RaphaelIT7 <64648134+RaphaelIT7@users.noreply.github.com>
Date: Sun, 16 Nov 2025 23:22:47 +0100
Subject: [PATCH] vphysics: expose two new virtual functions to support
 multiple physics environments

---
 game/shared/physics_shared.cpp |  5 +----
 public/vphysics_interface.h    | 11 +++++++++++
 vphysics/physics_object.cpp    |  6 ++++++
 vphysics/physics_object.h      |  5 ++++-
 4 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/game/shared/physics_shared.cpp b/game/shared/physics_shared.cpp
index 36c599827..67dd5515f 100644
--- a/game/shared/physics_shared.cpp
+++ b/game/shared/physics_shared.cpp
@@ -500,10 +500,7 @@ void PhysDestroyObject( IPhysicsObject *pObject, CBaseEntity *pEntity )
 		g_EntityCollisionHash->RemoveAllPairsForObject( pEntity );
 	}
 
-	if ( physenv )
-	{
-		physenv->DestroyObject( pObject );
-	}
+	DestroyPhysicsObject( pObject );
 }
 
 static void AddSurfacepropFile( const char *pFileName, IPhysicsSurfaceProps *pProps, IFileSystem *pFileSystem )
diff --git a/public/vphysics_interface.h b/public/vphysics_interface.h
index 8de9780fe..805dfb2d3 100644
--- a/public/vphysics_interface.h
+++ b/public/vphysics_interface.h
@@ -863,8 +863,19 @@ abstract_class IPhysicsObject
 	// dumps info about the object to Msg()
 	virtual void			OutputDebugInfo() const = 0;
 
+	// returns the buoyancy of the object.
+	// newly added by Valve in new builds since it was requested by Rubat to solve https://github.com/Facepunch/garrysmod-issues/issues/5696
+	virtual float			GetBuoyancyRatio( void ) const = 0;
+
+	// returns the environment this object belongs to
+	virtual IPhysicsEnvironment *GetEnvironment( void ) const = 0;
 };
 
+// Helper function - destroys the given object using the right environment
+static inline void DestroyPhysicsObject( IPhysicsObject* pObject )
+{
+	pObject->GetEnvironment()->DestroyObject( pObject );
+}
 
 abstract_class IPhysicsSpring
 {
diff --git a/vphysics/physics_object.cpp b/vphysics/physics_object.cpp
index e9f4a5ff7..b41947f0c 100644
--- a/vphysics/physics_object.cpp
+++ b/vphysics/physics_object.cpp
@@ -1454,6 +1454,12 @@ void CPhysicsObject::OutputDebugInfo() const
 	}
 }
 
+IPhysicsEnvironment *CPhysicsObject::GetEnvironment() const
+{
+	// Same as GetVPhysicsEnvironment but this function is exposed for the game dlls
+	return (CPhysicsEnvironment *) (m_pObject->get_environment()->client_data);
+}
+
 bool CPhysicsObject::IsAttachedToConstraint( bool bExternalOnly ) const
 {
 	if ( m_pObject )
diff --git a/vphysics/physics_object.h b/vphysics/physics_object.h
index 6f91235ff..f7921445a 100644
--- a/vphysics/physics_object.h
+++ b/vphysics/physics_object.h
@@ -187,6 +187,10 @@ class CPhysicsObject : public IPhysicsObject
 
 	void			OutputDebugInfo() const override;
 
+	[[nodiscard]] float	GetBuoyancyRatio( void ) const override { return m_buoyancyRatio; }
+
+	[[nodiscard]] IPhysicsEnvironment	*GetEnvironment() const override;
+
 	// local functions
 	[[nodiscard]] inline	IVP_Real_Object *GetObject( void ) const { return m_pObject; }
 	// dimhotepus: int -> unsigned short.
@@ -202,7 +206,6 @@ class CPhysicsObject : public IPhysicsObject
 
 	[[nodiscard]] inline intp		GetActiveIndex( void ) const { return m_activeIndex; }
 	inline void		SetActiveIndex( intp index ) { m_activeIndex = index; }
-	[[nodiscard]] inline float	GetBuoyancyRatio( void ) const { return m_buoyancyRatio; }
 	// returns true if the mass center is set to the default for the collision model
 	[[nodiscard]] bool			IsMassCenterAtDefault() const;