Alien slave beams stay forever if they exist during a level change

[SamVanheer]

If an alien slave's beams exist and the slave is in a transition volume when a changelevel occurs, the slave will transition to the next map but the beams will not.

Beams are set to never transition:

halflife/dlls/effects.h

Lines 107 to 113 in c7240b9

	int ObjectCaps( void )
	{
	int flags = 0;
	if ( pev->spawnflags & SF_BEAM_TEMPORARY )
	flags = FCAP_DONT_SAVE;
	return (CBaseEntity :: ObjectCaps() & ~FCAP_ACROSS_TRANSITION) | flags;
	}

So in the next map the slave's beam pointers will be null. When you then transition back to the previous map the beams that still exist there won't be patched up to the slave because the pointers are null now, and the beams will remain forever.
Repeatedly going between transitions while a slave's beams exist will eventually cause the game to run out of edict slots and exit with a fatal error.

To fix this the beams need to be set to be temporary:

m_pBeam[m_iBeams]->pev->spawnflags |= SF_BEAM_TEMPORARY; // Flag these to be destroyed on save/restore or level transition

This needs to be done in 3 places:

halflife/dlls/islave.cpp

Line 761 in c7240b9

m_pBeam[m_iBeams]->SetNoise( 80 );

halflife/dlls/islave.cpp

Line 807 in c7240b9

m_pBeam[m_iBeams]->SetNoise( 80 );

halflife/dlls/islave.cpp

Line 837 in c7240b9

m_pBeam[m_iBeams]->SetNoise( 20 );

This will also cause the beams to disappear if you save during an attack and then load it again. The actual attack still occurs, it's just the beam effects that will disappear.