Best way to detect a pistol start with ACS?

I think rather than checking what equipment/health/armor the player has, a better approach would be to keep track of whether or not the player was alive prior to starting the current level. This way the script will still work as intended, even if the player happens to run the game with a mod that for example changes the starting equipment.

I think one way of keeping track of this, would be with a special inventory item, which would be used to check if the player survived the previous map. On entering the map, a script would check if the player has the item, if they do, it's NOT a pistol start. If they don't have it (the player died and lost the item), it IS a pistol start. After these checks, and whatever actions follow them, the script would give the player the special inventory item again, so that on the next map load, the script can properly check for pistol start again.

Decorate example:

ACTOR ExitItem : Inventory
{
  +INVENTORY.UNTOSSABLE
}

ACS example:

#include "zcommon.acs"

// Runs for each player when first entering the map
script "PlayerEnter" ENTER 
{
	if (CheckInventory("ExitItem") > 0)
	{
		//NOT A PISTOL START
		//Do nothing.
		Print(s:"Not a pistol start!");
	}
	else
	{
		//PISTOL START
		Print(s:"You pistol started!");
		GiveInventory("Shell", 20);
		
		ACS_NamedExecute("PistolStartEvent", 0, 0,0,0);
		
		// Give the player the ExitItem so that if they survive
		// to the next map, we can detect it by checking for this item.
		GiveInventory("ExitItem", 1);
	}
}

// Runs for each player when respawning in multiplayer
script "PlayerRespawn" RESPAWN
{
	// Treat respawning as a pistol start?
	GiveInventory("Shell", 20);
	
	// Give the player the ExitItem so that if they survive
	// to the next map, we can detect it by checking for this item.
	GiveInventory("ExitItem", 1);
}

bool bEventScriptExecuted = FALSE;
script "PistolStartEvent" (void)
{
	// Prevent the script from running more than once per map,
	// regardless of how many player ENTER scripts try to execute it.
	if (bEventScriptExecuted == TRUE) Terminate;
	
	bEventScriptExecuted = TRUE;
	PrintBold(s:"Pistol start event!");
	
	// Code that adjusts the MAP during pistol start
	Spawn("Cyberdemon", 0.0, 0.0, 0.0);
}

I guess another possible approach could be using global variables and both an OPEN and UNLOADING script to keep track if a map was exited prior to loading the current map.

The item-based check should work also for other ways of resetting player inventory. I suppose one would have to try if it works with the automatic pistol start mods; there are at least two and I haven't checked how they work. If they just remove known weapons and ammo, reduce armor to 0, and set health back to 100, they wouldn't remove the exit item and thus create false negatives for that test.

4 minutes ago, Gez said:

The item-based check should work also for other ways of resetting player inventory. I suppose one would have to try if it works with the automatic pistol start mods; there are at least two and I haven't checked how they work. If they just remove known weapons and ammo, reduce armor to 0, and set health back to 100, they wouldn't remove the exit item and thus create false negatives for that test.

That's true, if they happen to use ClearInventory or ClearActorInventory, and then supply the player with starting gear, then the exit item would also be removed since it does not have the INVENTORY.UNCLEARABLE flag set.

But now that I think about it, there is also the possiblity that another pistol start mod could break this script if it runs right after this, and calls ClearInventory/ClearActorInventory and then removes the exit item, that this script gives the player at the end of the ENTER script. It does depend on which ENTER script gets executed first, but perhaps there should be a short delay before giving the player the exit item, to reduce the chance of another mod removing it right as they spawn.