better fix for CPhysHinge::Activate() crash, fix for saverestore crash in CPhysSlideConstraint::Activate() pointing to VelocitySampler::GetRelativeVelocity()

Author: pivotman319-owo

src/game/server/physconstraint.cpp

@@ -940,16 +940,21 @@ void CPhysHinge::Activate( void )
 	m_soundInfo.OnActivate(this);
 	if (m_pConstraint)
 	{
-		if (m_soundInfo.m_iszTravelSoundFwd != NULL_STRING || m_soundInfo.m_iszTravelSoundBack != NULL_STRING || m_soundInfo.m_pTravelSound != nullptr)
+		if (
+				m_soundInfo.m_iszTravelSoundFwd != NULL_STRING ||
+				m_soundInfo.m_iszTravelSoundBack != NULL_STRING ||
+				m_soundInfo.m_pTravelSound != nullptr ||
+				m_pConstraint->GetAttachedObject() != nullptr
+			)
 		{
 			m_soundInfo.StartThinking(this, 
 				VelocitySampler::GetRelativeAngularVelocity(m_pConstraint->GetAttachedObject(), m_pConstraint->GetReferenceObject()) ,
 				m_hinge.worldAxisDirection
 			);
-		}
 
-		SetThink(&CPhysHinge::SoundThink);
-		SetNextThink( gpGlobals->curtime + m_soundInfo.getThinkRate() );
+			SetThink(&CPhysHinge::SoundThink);
+			SetNextThink( gpGlobals->curtime + m_soundInfo.getThinkRate() );
+		}
 	}
 }
 
@@ -1277,13 +1282,24 @@ void CPhysSlideConstraint::Activate( void )
 	Vector axisDirection = m_axisEnd - GetAbsOrigin();
 	VectorNormalize( axisDirection );
 	UTIL_SnapDirectionToAxis( axisDirection );
-	m_soundInfo.StartThinking(this, 
-		VelocitySampler::GetRelativeVelocity(m_pConstraint->GetAttachedObject(), m_pConstraint->GetReferenceObject()),
-		axisDirection
-		);
+	if ( m_pConstraint )
+	{
+		if (
+			m_soundInfo.m_iszTravelSoundFwd != NULL_STRING ||
+			m_soundInfo.m_iszTravelSoundBack != NULL_STRING ||
+			m_soundInfo.m_pTravelSound != nullptr ||
+			m_pConstraint->GetReferenceObject() != nullptr
+			)
+		{
+			m_soundInfo.StartThinking(this,
+				VelocitySampler::GetRelativeVelocity(m_pConstraint->GetAttachedObject(), m_pConstraint->GetReferenceObject()),
+				axisDirection
+			);
 
-	SetThink(&CPhysSlideConstraint::SoundThink);
-	SetNextThink(gpGlobals->curtime + m_soundInfo.getThinkRate());
+			SetThink(&CPhysSlideConstraint::SoundThink);
+			SetNextThink(gpGlobals->curtime + m_soundInfo.getThinkRate());
+		}
+	}
 }
 
 void CPhysSlideConstraint::Precache()

src/game/server/physconstraint_sounds.h

@@ -187,6 +187,10 @@ class ConstraintSoundInfo
 Vector VelocitySampler::GetRelativeVelocity( IPhysicsObject *pObj, IPhysicsObject *pReferenceFrame )
 {
 	Vector childVelocity, parentVelocity;
+
+	if (!pObj)
+		return { 0,0,0 };
+
 	pObj->GetImplicitVelocity( &childVelocity, NULL );
 	pReferenceFrame->GetImplicitVelocity(&parentVelocity, NULL);