ZZT Notes

Here are some notes and code snippets for ZZT which may be useful to you, or future me, if I do anything further with the engine.

One of the unique aspects of ZZT is its capacity to be used as a medium for publishing about ZZT itself. Various company magazines, best-practice guides, and reference encyclopedias (collections of cool things you can do) were created throughout the years. However, the drawback of publishing information in this way is that you can't get to it easily without loading the world files in ZZT and actually playing them. The Museum of ZZT File Viewer helps greatly with this visibility problem, but the content is still spread across several publications.

This page will start out as a few random notes, but I hope to eventually map out the encyclopedias and attribute sources where possible.

ZZT-OOP

Counters

Set the player's health to a specific value

ZZT infamously only provides addition and subtraction to a handful of pre-defined counters. The Health counter can be directly set to a specific value by abusing the endgame command:

@setHealth
#end
:touch
#endgame
#give health 100
#end

Endgame normally sets the player's health to zero and triggers a Game Over state, but if you immediately give the player health afterwards, ZZT will not catch that the game should have ended, and will continue on as if nothing happened.

Detect when the player enters a board

Super ZZT provides a new label for making objects do things whenever the player enters a board. In ZZT, under certain circumstances, it is possible to do this by monitoring the Time counter:

@timeCheck
#cycle 1
:a
#take time 1 enteredboard
#give time 1
/i#b

:enteredboard
#give time 1
enteredboard label tripped.
/i
#all:enter
#a

Caveats: The board should not have a time limit specified, and if the player takes built-in damage (hit by a bullet or creature), this will also reset the Time counter to zero and cause the loop to trigger. ZZT-OOP #give / #take commands do not have this side effect.

The Time counter is always available to mess around with in ZZT-OOP, even when a time limit is not specified on a given board, and it is always set to zero upon entering a board or upon taking built-in damage. Its value will be preserved when restoring from a save file.

Display an external text file

An undocumented menu option (!-FILENAME;) will display the contents of a specified text file. These files may include additional menu links, but the text will not be executed as ZZT-OOP.

@readDoc
#end
:touch
What do you want to read?

!-HELLO.TXT;Read HELLO.TXT!
!x;Never mind.
:x
Okay.
#end

If the file doesn't exist, nothing happens. Paths may be specified as well. For example, you could display Z:\AUTOEXEC.BAT when running within DOSBox.

This may be useful for conserving limited memory in a large world file, or to allow blocks of text to be viewed on multiple boards without duplicating the text everywhere.

Entities that are visible in the dark

Dark boards in ZZT mask the entire screen in a grey fog, showing only the player, passages and torches. The player can light torches to view a small radius of the surrounding area. Abuse of these entities can allow you to fill in negative space and create animations that otherwise wouldn't be visible.

Also known as the Kangaroo effect, the namesake of this wiki.

The following entities are visible on dark boards, and can be used to display a limited set of patterns or solid colors on an otherwise grey screen:

• Torches. The safest thing to use.
• Passages, both with stats and statless. This can cause undesired warping to other boards, particularly the title screen with statless passages.
• Player Clones, both with stats and statless.
• Kryptonite Text -- Entity ID 54, which shows up as blinking white text. This is an undefined entity and its presence on a board is capable of crashing ZZT!

Torches and passages cannot be pushed by anything, but player clones and Kryptonite text may be moved by non-player entities such as objects and boulders. Player clones carry some potential side effects, particularly with board edge linking if those clones are up against an edge. (TODO expand on this.) These entities in general can be set as the "under" terrain for entities with stats, so that when the upper object moves, the entity underneath shows through the fog mask.

Attribution

• Kryptonite Text, presented and coined by Jur, 27 Oct 2018, Discord of ZZT