[Vanilla Level Editing] Lesson 11: Let's Get The Hell Out Of Here!

[Linguica]

The last few lessons have all concentrated on special line attributes that cause changes in targeted sectors. This lesson will look at the few remaining special types of lines and also revisit the sector’s special characteristic. None of the actions examined in this lesson result in changes to sectors, however; they all act on players, monsters, or both.

The WAD that has been building in previous rooms will be developed further in this lesson in three more Sorties. The first of these will finally add an escape route to the embryonic maze area added several Sorties ago. The second of this lesson’s Sorties will add an exit to the WAD as a whole, while the last will sort out the awarding of credits for the discovery of the WAD’s secrets.

This room starts, though, with a trip through DOOM’s teleporter.

[Linguica]

TELEPORTS

You will already be familiar, no doubt, with the way a DOOM teleport operates: the player steps into it, vanishes, and rematerializes somewhere else. You have probably guessed by now that a teleport’s action is provided by yet another special type of line. This is indeed the case. DOOM needs rather more than just the line, though, to implement a functioning teleport.

[Linguica]

COMPONENTS OF A TELEPORT

To build a teleport, three things are required:

• A teleport trigger line: This is the line that the player steps over to “enter” the teleport and trigger the transportation action.
  
• A destination sector: This is where the player rematerializes.
  
• A landing spot: This marks the precise location within the destination sector where the rematerialization takes place.
  

Each of these three items must be in place and properly set up for a teleport to operate. Let us look at how each of these three items is provided.

[Linguica]

TELEPORT TRIGGERS

Teleport triggers are provided through special line-types. (As the only really active component of a teleport, these lines are often just termed “teleporters.”)

These triggers act much like any other walk-through trigger line, with the action taking place as it is crossed. The familiar teleport “pads” are simply sectors with all of their passable boundaries set up as teleport triggers. When anything steps into the sector, it crosses an active line and is whisked away to the appropriate destination. This arrangement creates the illusion that the pad itself is active.

Unlike other walk-through actions, teleport lines can only be triggered from one side: their right. If you think about it, this makes a lot of sense. It allows a teleport pad to act as the destination from another teleport (a common arrangement) without having one of that pad’s own teleport lines transport the player somewhere else as soon as they try to step from it.

To make a teleport pad active on entry and not on exit, all of its active lines should be arranged with their right sides facing out from the pad sector.

[Linguica]

TELEPORT DESTINATION SECTOR

Like other special lines, each teleport trigger needs be tagged to a sector — in this case, to act as a destination. Each trigger should be tagged to only one sector; a player cannot be sent to multiple destinations simultaneously. If a trigger is tagged to more than one sector, DOOM will take the lowest-numbered one to be the destination.

It is possible, however, to have more than one teleport trigger tagged to the same sector. This allows all of a teleport pad’s active lines (or, indeed, several different teleports) to deliver to the same location.

[Linguica]

TELEPORT LANDINGS

DOOM needs to know more than just the sector in which rematerialization will occur, though — it needs the precise spot. This is marked by the placing of a special category of Thing within the destination sector: the teleport landing. Each teleport destination sector must have one of these, or the teleport will not operate.

Teleport landings use the same attributes and flags as all other categories of Thing. The facing-angle attribute is used to determine which way players and monsters will face as they materialize. The skill-level flags can be used to indicate whether individual teleport landings are present (or absent) at particular difficulty settings of the game. DOOM will only consider those present at the game’s current skill setting when looking for a particular teleporter’s destination. This can be used to vary the precise location (and/or facing) of a teleport landing with skill setting, although this variation can only take place within the one sector, of course.

If a destination sector contains more than one teleport landing, the one with the lowest number (usually the first placed) will be used. If no teleport landing can be located within the destination sector at the game’s current skill setting, the teleport remains inactive.

[Linguica]

BUILDING A TELEPORT

Here is a summary of the steps involved in implementing a fully operational teleport:

• Choose a line or lines to act as the teleport trigger. If you are using a particular area as a teleport pad (and you don’t have to, of course), then make sure that you use all of the passable lines surrounding the pad—unless you want players and/or monsters to be able to walk onto the pad from some directions without teleporting.
  
• Flip all of the chosen trigger lines so that their right sides face the direction from which you want the line to be triggered. Typically, this will mean that all of the passable lines surrounding a teleport pad will have their right sides facing out.
  
• Place a teleport landing where you want materialization to occur. Make sure there is sufficient head-room for players to arrive at this spot. Decide which way you want players and monsters to be facing when they arrive here and adjust the teleport landing’s facing angle to suit.
  
• Tag each of the teleporter lines to the sector containing the teleport landing.
  

These are the essential steps in producing a functioning teleport. You can, of course, arrange for more complex teleport pads that have their component triggers tagged to different sectors. Such teleports will then deliver to differing locations depending upon which line is crossed.

[Linguica]

TELEPORT TRAPPINGS

Teleports may be as conspicuous or as invisible as you feel is appropriate in your WAD. It is often a good idea to mark teleport destination points with distinctive patterns, especially in WADs that are designed for multiplayer use. This provides players with at least some warning of potential telefrag spots and discourages them from lingering there.

If you want your teleports to look like teleports, the GATE_ series of flats provides the classic set of ceiling and floor textures used in id Software’s own levels. There is no special trick to the use of these. Simply make your teleport pads a standard 64-units square, aligned precisely along grid lines.

[Linguica]

MONSTERS IN TELEPORTS

DOOM v1.666’s monster-only teleporters are useful for enabling monsters to move around a WAD in a way that prevents players from following them. A discussion of the use of these, and other useful techniques for using teleports as monster-laden traps, appears in the next lesson, “Populating Your DOOM World.”

[Linguica]

WAD SORTIE 24: USING TELEPORTS

Teleports are useful devices for getting players out of sticky situations without requiring a lot of additions to a WAD. To demonstrate this, this Sortie shows you how to add a simple way out of the maze. After that, I’ll also show you how to use teleporter lines to make life a little trickier for the players.

[Linguica]

A STRAIGHTFORWARD TELEPORT

Let us start by adding a teleport as an exit from the maze for players who have entered via the one-way marble staircase. Decide where you would like this to be. I’ve put mine at the end of one of the twisting areas in the left part of the maze, but it could be almost anywhere. All it needs is a single 64 x 64-unit grid square.



Be careful how you add to the maze, by the way. It is easy to wreck the special lighting operations here.

When you have your new teleport sector properly defined, apply appropriate settings to it — you will need to use a lighting value of 144 to keep the lighting tricks working, remember — with one of the GATE_ textures on the floor and the ceiling. Use whatever wall textures you fancy, wherever they are needed.

Next, make sure that all of the entrance lines to your new sector have their right sides facing out from it. Put line-type 97 (WR Teleport) on them all, tagged to a suitable destination sector. This could be anywhere, but I feel it should be somewhere that the player has already visited, so that the teleport is viewed as a means of escape from the stair-trap, not as a way on to new locations. I recommend using the starting sector — the hexagonal room.

Finally, switch to Things Mode, right click to add a new thing in the hexagonal sector, and select the Teleports category. Place a teleport landing somewhere in the destination sector. Save the WAD as D2WAD24.WAD, and then give it a whirl!

[Linguica]

SOME TELEPORT TRICKS

A more elaborate arrangement of teleports can be used to make whatever is located within the donut rather harder to obtain.



These new areas use an array of teleporters and switches to provide the player with a little puzzle. This operates as follows:

• The switch to operate the donut is in plain view on the rear wall of this alcove. This is also the only alcove that the player can enter from the floor of the room. All of the others are either raised too high or are hidden behind doors. The problem is that the entrance line to this alcove is a teleporter line. As players enter, they are immediately transported to Area 2, without any hope of reaching the switch.
  
• This alcove has a switch on its rear wall to activate a small sector adjacent to Area 3 as a lift. The player will have to run across the room to catch this lift before it goes back up. The floor heights of areas 2 and 3 are such that the player cannot enter either of them from the main room’s floor.
  
• This area can only be entered using the lift activated from Area 2. The alcove contains no switch, but it does have a teleport trigger across its entrance from the lift, which transfers the player to Area 4.
  
• This alcove houses another switch, this time to raise the door that has been hiding Area 5 (and which is not in view from here!). The player has five seconds to find it and get through it, before it closes.
  
• Behind the secret door raised by the switch in Area4, is another teleporter. This takes the player (finally!) back to Area 1 so that he may now press the switch to consume the donut — provided he can still remember what he was trying to achieve after all that.
  

Implementation of this puzzle is not complicated, merely a little tricky to keep track of. Start by drawing and making each of the new areas. Area 5’s two floors should both be at the same height as the main room floor. Set the floor height for the first alcove 24 units higher; all of the others need to be even higher so that they cannot be entered directly. Choose the remaining sector settings for yourself. You may wish to consider how many of the teleports you want to have looking like teleports. Make sure you leave enough headroom for players not to become stuck when they materialize.

Use suitable members of the GRAY series of wall textures (with appropriate pegging) for all of the new walls. There are a couple of suitable switch textures to choose from. Don’t forget that the door in front of Area 5 needs to be hidden. Careless texture alignment will give its location away.

Work round each of the switch and teleporter lines, placing appropriate special attributes and tags, making sure that each of the teleporter lines faces the correct way. Be sure to use repeatable actions for each of the switches that require the player to run to complete the next stage of the puzzle. Also, don’t forget to disconnect (and hide) the temporary switch for the donut before connecting in the real one.

Finally, place teleport landings in each of the destination sectors. Arrange these so that they face out from the alcoves, into the room. This means that the switches will always be behind the player as they materialize. Figure 11.4 shows the location of each of the teleport landings required. Note that the numbers in this figure show which of the areas in Figure 11.3 have trigger lines tagged to the indicated sector.

Notice that I’ve also added a key as the reward for solving the puzzle — a yellow one.

Save the WAD as D2WAD24A.WAD and see how well you did. Did you solve the puzzle of building it? How well does it play? Make whatever adjustments and changes you feel are necessary before going on. You might like, for instance, to reverse the way that the teleporter line of Area 3 faces. This will enable players to enter the sector without being teleported immediately. They will then probably hunt around in vain for some switch. Only when they give up and decide to leave will they be teleported on.

[Linguica]

ENDING THE LEVEL

The final category of special line-types are the exits. These bring about the termination of the level in progress, displaying the appropriate intermission screen, with its tally of kills and so on. In addition to using special lines, DOOM also has another method of ending a level. Before looking at that, though, let us examine the way lines are used to signal the exit from a level.

[Linguica]

EXIT SWITCHES AND TRIGGERS

DOOM provides two mechanisms for ending a level with lines: a walk-through exit, and a switch- activated exit. Naturally, these lines can only be activated once. Table 11.2 gives the codes that are available for producing exits.

STANDARD EXITS

Standard exits take the player to the next higher level number (after the intermission screen) except for the last mission of the episode, of course, which ends the episode. Mission 8 is the last of each DOOM episode; Level 30 ends DOOM II. If an external patch WAD does not contain the subsequent map, DOOM will load the original from the IWAD file.

SECRET EXITS

Secret exits take the player on to the appropriate secret level (again, after the intermission screen). In DOOM, this is always Mission 9 of the current episode; in DOOM II it is either Level 31 or 32, depending upon which “half” of the game the current map is in.

All exits from the secret missions are hard-coded to return the player to the same subsequent map as in the original game.

FATAL EXITS

A final way of ending a level is provided through one of the special sector characteristics — 11. This setting applies the high rate of damage to reduce the health of a player in the sector. When it falls below 11 percent, the level ends. Most WADs make it impossible to escape such a sector, to ensure that the mission does indeed end as a consequence of the player reaching this spot.

Although this action operates as a standard exit, taking the player on to the next mission, it makes more sense to use it as a device to end a complete episode — just as id Software does.

[Linguica]

THE NEED FOR EXITS

It is desirable for all levels (especially those intended for single-player use) to have an exit; otherwise players will not know whether they have completed it or not. This may sound trivial, but remember that it is only through triggering an exit action that players are given their tally. Without this tally, they will not know whether all secret locations have been found, all monsters disposed of, or all goodies collected. Such things are less important in WADs designed primarily for Deathmatch play, but most players still like to see exits and use them to end the game.

Exits are also vital in multi-level WADs, of course, to enable the player to progress to the next mission. You can have as many exits in each map as you consider necessary.

[Linguica]

MAKING EXITS OBVIOUS

In most players’ view, it is also important that the role of a switch that ends a level should be obvious before it is pressed. There is nothing more frustrating than pressing a switch that you have fought hard to gain in the belief that it opens a door, only to discover that it ends the level instead! Few players will be impressed with exits such as this.

Once again, the designers at id Software have provided several textures for you to use to make your exits conspicuous. The most obvious is, of course, the large red exit sign. Less obvious, perhaps, but still recognizable to most DOOM players, is the distinctive techno-door texture that id Software’s designers use on the doors to most of their exit anterooms. This is the EXITDOOR texture.

Notice how this texture is a multi-function texture, by the way. The pattern for the face of the door only takes up one half of the pattern; the remainder includes three additional textures. These are intended for use on the reveals of the recesses to either side of the door. Note the symmetrical form of the patterns to the side of the door.



The pattern for the left reveal is obtained by using an X-offset of 64 pixels into the EXITDOOR texture; the pattern for the right reveal appears when an X-offset of 88 pixels is used. The lines for each reveal must be precisely 24 units long, of course, to take these patterns. If the lines are too long, the patterns will not repeat; there will merely be spill-over into the next part of the texture.

The last 16 pixels of the EXITDOOR texture provide an additional lighting-panel pattern. Use an X-offset of –16 to apply this to any suitably sized line. Incidentally, notice that the EXITDOOR texture is only 72 pixels high. It will therefore not tile correctly if applied to spaces that are too high for it.

[Linguica]

WAD SORTIE 25: ADDING AN EXIT

This WAD Sortie will add an exit to your WAD to enable a player to end the level and move on to the next. This exit will be located in an area off the outdoor crescent, just to the west of the donut room. It will be located beyond a new yellow-keyed door, requiring the player to successfully complete the donut-room’s puzzle before being permitted to leave this level.

[Linguica]

THE APPROACH

Start by building a yellow-keyed door off the southwest end of the outdoor crescent. Use suitable recesses, a door width of 256 units and BIGDOOR2 on the door itself to match all of the other doors off this area. Then use whatever wall textures and sector settings you feel are appropriate for the areas beyond the door — an open chamber and a corridor leading on towards the exit room itself. My WAD (D2WAD25.WAD) uses ASHWALL for the walls of the chamber and STONE2 for the corridor. The corridor floor is 16 units below the chamber floor and has a much lower ceiling. I’ve also set the lighting levels quite low.

The corridor ends in a funnel-shaped sector that is designed to bring the corridor width down to 64 units and the height down to 72 to enable the EXITDOOR texture to be used on the door ahead.

[Linguica]

EXIT ANTEROOM, WITH CHARACTERISTIC DOOR

The two walls of the funnel-shaped recess sector use the EXITDOOR texture on them where they abut the door. The lines for these have been made 24 pixels long (they run north-south aligned to make this easier to arrange) and have the appropriate X-offsets to use the symmetrical door-reveal patterns of this texture, as previously discussed. The face of the door itself also carries the EXITDOOR texture on its upper texture slot. Figure 11.6, shown previously, is, in fact, a view of this door in my D2WAD25.WAD. Both sides of this door should be of special type 1 (DR Door Open Wait Close).

Beyond the door (and an inner door-recess sector) is the main exit anteroom itself. The recess on this side of this door has short walls abutting the door sector. These are 16 units long and use the right-most portion of the EXITDOOR texture. The short lines that connect the inner recess to the main anteroom use the STONE2 texture, as do the rest of the walls beyond the door.

Ceiling and floor heights for the areas around the door to the anteroom are given in the table below. You may need to adjust these (or those of the approach areas to the south) to provide a better tie-in with your corridor. The room heights should be maintained if you want the wall textures to align correctly.

[Linguica]

THE EXIT SWITCH

The switch that will trigger the end of the level is placed in an alcove in the western wall of the anteroom. This is a standard 64-unit wide switch alcove with the SW1STON1 texture on its back wall, with its lower unpegged flag set. The alcove should be 72 units high, with the same floor height as the rest of the room. Place a special attribute of 11 (S1 Exit: standard) on this line. No tagging is necessary. This creates the exit switch.

[Linguica]

AN EXIT SIGN

The fact that this is an exit switch needs to be signalled to the player. The EXITSTON texture could be used on the wall over the alcove — it provides the red EXIT lettering on the appropriate stone texture — but I prefer a sign suspended from the ceiling. To make this, another sector is needed, just east of the switch alcove. This sector should be 64 pixels wide by 16 pixels deep and located close to the western wall as seen in Figure 11.8, shown previously.

This sector has the same settings as the main room, except for the ceiling, which has been lowered 16 units to create a set of essential upper textures around it. The 16-pixel high EXITSIGN texture is used on all of these essentials, with X-offsets applied so that the appropriate parts of this multifunction texture appear correctly on each face (–16 on all faces).

[Linguica]

FINISHING OFF

Finally, to save you from having to run around like crazy in the donut room to acquire the yellow keycard just to test this new area out, place another one in the crescent by the yellow-keyed door. Save the WAD as D2WAD25.WAD, and then go try it out. You should now be able to progress from your WAD to the standard second level of the game.

[Linguica]

SECRET AREAS

Amongst the items reported on a level’s final tally screen is the percentage of the secret areas of the map that the player successfully located. You may have noticed that no matter how many of your own “secret” areas you visit when you play your WAD, your secret tally is always 0 percent when you trip the exit switch. This is because DOOM does not yet know that your level has any secrets!

[Linguica]

MAKING SECRET AREAS

You have seen the ways in which areas can be kept hidden from players. However, simply hiding doors and other entrance points to these areas does not make them “secret” as far as DOOM is concerned. An area’s secret nature must be notified to the game engine if it is to be included in the reckoning of the final tally. This is done by setting a sector’s special characteristic to the value 9. A player entering a sector with this special value will be credited with the discovery of a secret area.

Note that the use of their special characteristic in this way precludes such secret sectors from possessing other special characteristics, such as fluctuating light levels or damaging properties.

[Linguica]

TALLYING SECRETS

The game engine calculates the final tally of secrets that have been located by counting up the total number of sectors with a special characteristic of 9 and determining what proportion of these have been entered by the player during the game.

To provide the player with a useful indication of what proportion of secret locations have been found, you should apply the secret credit characteristic carefully. Generally, you should only use one occurrence of the special value for each area that is hidden. Remember that players are generally unaware of the distribution of sectors — they see only rooms and such like. A room consisting of three sectors behind a hidden door should not grant more than one secret credit.

Furthermore, credits should be awarded sooner rather than later. The best location would be either the entrance sector itself, or the first sector beyond it. This way, the player is not forced to walk all around a secret area just to collect the credit for its discovery. Watch out too for secret areas that have more than one possible way in. Make sure that players will pass into the credit-awarding sector no matter what entrance to the area they use.

You should also ensure that players are given good reason to enter a secret area. If a player opens a secret door but does not enter because the small room beyond appears empty, DOOM will consider there to be an undiscovered secret area when the mission finishes. This will result in frustrated play- ers wandering around trying to locate that last secret they have already found. The placement of a few bonuses in the room would have prevented this.

[Linguica]

COMPULSORY SECRET DISCOVERIES

It is important for the correct feel of a game that players easily equate the secret credits they have been awarded with the locations they have found. You should not award secret credits for areas that players are forced into locating because of traps. Such areas are rarely seen as “secret” by players and you will therefore disturb their own mental count of how many secrets they have located by awarding credits unnecessarily. Finding a hidden exit from a room in which a player has been locked is usually its own reward!

Finally, even if your level doesn’t use any secret locations, you should make sure that one sector does award a secret-discovery credit. Use either the start sector or the one with the exit switch — one that the player is guaranteed to pass through. This ensures that the tally screen reports 100 percent of secrets located, rather than 0 percent when the level ends. This simple addition to your WAD will save players much frustration from wandering around looking for secrets that are not there. (If only id’s designers had taken this advice with DOOM II!)

[Linguica]

WAD SORTIE 26: AWARDING SECRET CREDITS

This final Sortie from the current lesson examines the WAD that you have built and makes recommendations about which of your current sectors should award secret credits.

[Linguica]

SETTING THE SECRET AREAS

Some of the WAD’s candidates for awarding secret-discovery credits are:

• The marble one-way stairs
  
• The hidden room at the top of these stairs
  
• The platform room
  
• The southern courtyard
  
• The hidden room in the southwest corner of the courtyard
  
• The crusher room
  
• The sniper's den
  
• The hidden room off the southwest staircase
  
• The string of rooms behind the shot-activated doors off the blood pool
  
• The room north of the blood pool
  
• The causeway across the pond
  
• The imp ledge outside the northern window of the platform room
  

Let us consider the case for each of these areas in turn. To make a sector award a discovery credit, simply set its special characteristic to the value 9.

[Linguica]

THE MARBLE ONE-WAY STAIRS

These stairs are currently located behind a secret door that is activated from a rather obvious switch. Currently, this area of the map is away from the main flow of the WAD. Decide for yourself whether it warrants inclusion as a secret area. If you decide in favor of it, I recommend using the entrance from the southwest passageway as the credit-awarding sector.

THE HIDDEN ROOM AT THE TOP OF THE MARBLE STAIRS

This room is only hidden in the sense that players may not notice it as they pass. Its opening is triggered from further along the corridor — at which point they will definitely discover its presence! They may not be able to fathom the way to get in there, though. On balance I would award a secret-discovery credit here.

THE PLATFORM ROOM

The entrance to the platform room is currently semi-hidden and its switch is not too obviously attached to it. It seems a little generous to award a discovery credit for this, though.

THE SOUTHERN COURTYARD

This area can only be gained once the player has located and tripped the switch in the hidden room. The area is hardly secret, however. How you view secret areas will determine whether you mark this as one or not. I probably wouldn’t.

THE ROOM IN THE SOUTHWEST CORNER OF THE COURTYARD

This strikes me as a perfect candidate for a secret-discovery credit. By awarding a secret credit here, credit is effectively given also for finding the courtyard itself, because this credit cannot be collected until the way into the courtyard has been found.

THE CRUSHER ROOM

The string of crushers is located behind a door that is hidden and shot-activated. I would probably award a secret-discovery credit here. I would also let the entrance sector be the one that awards the credit. The discovery is awarded then, even if the player doesn’t run the gauntlet of the crushers. (Just call me generous.)

THE SNIPER’S DEN

I would also award a credit here, too—that way the player earns extra credit for braving the crushers and noticing the door beyond. (Not that it’s hidden, though. I said I was generous, didn’t I?)

THE ROOM OFF THE SOUTHWEST STAIRCASE

The case for this room is similar to that for the room at the top of the marble stairs. It is easier to get into though — its door latches open — and there is the added complication that the special characteristic will already be in use if you left this area with flashing lights. As this particular room contains the switch that will permit access to other areas already marked as secret, there seems little point in awarding a separate credit here. I’d leave this area out of the secrets list.

THE CORRIDOR BEYOND THE BLOOD POOL

The discovery of these areas is a vital step in the completion of the arena section of the WAD. There is little point in awarding discovery credits here, in my opinion.

THE ROOM NORTH OF THE BLOOD POOL

The opening mechanism for this room is not obvious in its purpose and is sufficiently far from the room itself for careless players to miss it. It is not central to the overall scheme of the WAD — I suggest that this room should award a credit.

THE CAUSEWAY

There seems to be no point in awarding credit for finding the causeway across the pond: as things stand, this is the only escape from the lower area of the arena.

THE IMP LEDGE

It may not be immediately obvious why I have included this in the list of secret areas, as it may not seem particularly secret to you. Bear in mind, though, that this area does start out hidden from the platform room side. Also, if the lift up to it from the arena were to be made less conspicuous, players may not find this ledge. This, coupled with the fact that currently no secret credits are awarded at all for successfully attaining this area of the map — it involves the correct location of a number of switches, remember — means that I would probably award a secret-discovery credit to players who do manage it. (I may change my mind later, though!)

[Linguica]

COLLECTING THE CREDITS

When you have decided which areas are to award credit for their discovery and have set all of the appropriate sectors’ special characteristics, you should save your WAD as D2WAD26.WAD. Check that your Player 1 Start position is back in its normal location in the hexagonal room, and take a run through your empty WAD, to check that you can collect all of the secret credits. You may wish to revise your original opinions as to what should be secret after you’ve been to them all.