Level Transition (Portal 2)

=Coop=
Here is a way to make a sequence of test chambers for coop.
==Create Your Map==
First, create your coop map. Add another , setting its VMF file to instances/coop/coop_lighting_ents.vmf. (All we're using is the inside.)
==Modified Endlevel==
The end-of-map logic lives within the instances/coop/coop_endlevel_room.vmf instance. Load this map within Hammer and save a copy of it—e.g., my_coop_endlevel_room.vmf. 
In a little room in this map you'll find a named transition_script. (You can use the Find Entities command to select it.) You'll see that its Entity Scripts property is set to debug_scripts/mp_coop_transition_list.nut.
Don't modify that file! It's part of Portal 2, and you don't want to touch it. Instead, change the Entity Scripts property to point to a script of your own—e.g., debug_scripts/my_mp_coop_transition_list.nut. Then, save the map.
Go back to your coop level, select the func_instance containing the endlevel room, and edit its VMF file to point to your modified version.
==Modified Script==
Now go to scripts/vscripts/debugscripts in the Portal 2 installation and create this script. (Again, don't touch the Valve script.) All you really need is something like this: 
// Map order
MapPlayOrder<- [
"mp_coop_easiest",
"mp_coop_easiest_two"
]
function TransitionFromMap()
{	
	local nextmap = -2
	
	// Loop through maps
	foreach( index, map in MapPlayOrder )
	{
		if( GetMapName() == MapPlayOrder[index] )
		{
			// This is the map we're on
			nextmap = -1
		}
		else 
		{
			if (nextmap == -1)
			{
				// This is the first map past that one
				nextmap = index
			}
		}
	}
		
	printl( "nextmap = " + nextmap )
		
	if (nextmap > 0)
	{
		// We found a map; go to it
		EntFire( "@command", "command", "changelevel " + MapPlayOrder[nextmap], 1.0 )
	}
	else
	{
		// No map found; we're done
		EntFire( "@command", "command", "disconnect", 2.0 )
	}
}
The array at the top, MapPlayOrder, is your list of maps in order. (For those not familiar with Squirrel, note that each map is enclosed in quotes, and there must be a comma in between each map. That is, the last map doesn't get a comma after it. And don't lose that final bracket!)
To go to the lobby after your maps, add "mp_coop_lobby_2" as the last map in the list (MapPlayOrder).
==Testing==
Make the additional coop maps, using your modified endlevel room instead of the default one. Compile them all.
Now you can test your maps. Just load the first map and play it. When you get to the end, Portal 2 will switch to the next map. Once it gets to the end, it will simply exit to the main menu.
(This method could be extended to create a hub as in the game. Look at mp_coop_transition_list.nut for ideas.)
=Single-Player=
The single-player case is similar. 
==Modifed Transition Manager==
In single-player, the end-of-level logic lives in the in the maps/instances/transitions folder. Load this map in Hammer and save it under another name, such as my_arrival_departure_transition_ents.vmf.
Within this instance, the smallest room contains a named @transition_Script. Its Script Entity property points to transitions/sp_transition_list.nut.
Don't modify that file. Instead, point the property to a copy of your own, e.g. transitions/my_sp_transition_list.nut. 
While you're here, you might optionally change the named @end_of_playtest_text to display a line of text after the last map. Just change the Message Text property.
Save your modified VMF file.
==Modified Script==
There's a lot going on inside this script, and undoubtedly a much simpler version would do for a simple series of testchambers; however, here's the minimum you must do.
Look for the list of maps and search for "demo_paint," the last map in the file. Add your maps after this. (Again, map names are in quotes, and there's a comma afterward except for the last map. And don't lose the final bracket.) 
The result should look like this:
// ---------------------------------------------------
// 	Demo files
// ---------------------------------------------------
"demo_intro",
"demo_underground",
"demo_paint",
// ---------------------------------------------------
// 	Your title
// ---------------------------------------------------
"your_first_level",
"your_second_level"
]
The actual logic to change maps is in TransitionFromMap. To make Portal 2 exit to the main menu after displaying the end text, look for these lines:
		EntFire( "end_of_playtest_text", "display", 0 )
		EntFire( "@end_of_playtest_text", "display", 0 )
and add this line after them:
		EntFire( "@command", "Command", "disconnect", 2.0 )			
Save the file. (Again, you're saving your modified copy of this .nut file—don't overwrite the Valve file!)
==Compile and Test==
Make and compile the additional maps. You can now go back to your first map and run it from Hammer; Portal 2 will load and put you into your first map. When you get to the end, it'll run the next map from the script and exit to the main menu when all are done.
Category:Portal 2 Tutorials