GUI - Triggering for Dummies (the basics)

Prerequisits:


Alright so there are a few things we are going to look at:


Variables

Alright, essentially a variable is something that stores information, there are many types of information that they can store but every variable has a defined type. IE: a point variable can not store a unit, but a unit variable can. For example, we are going to use an action to save a variable of the position of a unit every time it is damaged.

Example
Events
 Any unit takes fatal or non-fatal damage
Local Variables
 Point < no point >
Conditions
Actions
 Set Point = position of triggering unit

this saves the variable: Point, as the position of the unit that was last damaged when it was damaged. Now we will go over a few different parts of variables:


Indexes/Arrays:
An array variable is essentially a variable with multiple instances to it (or it can save multiple pieces of information), array variables can have a max array set by you in the editor, now this array includes 0 so if you are using it to get a player number or something of that sort it will not work if your player number becomes equal to the max array (the actual arrays for the variable are 0 through max - 1) a variable would look like this in your editor if it has an array: variable[array]. Arrays are capable of being multi-dimensional (up to 4 dimensions) like this: variable[dimension 1][dimension 2][dimension 3]. Each of these dimensions is refered to as an index and can only be defined by an integer, for example: variable[1] works, but variable[a] doesn't.

Constants:
A constant is the only type of variable that can not be an array. It is a variable that can not be set by actions because it is, as the name says, constant. It remains the same value throughout the entire game, but what it stays can be set by changing the default value. These are mainly used for systems that have edit-able options, so that when a player copies the system into their map, they can change a constant like a setting.

Global Variables:
These are variables that can simply be used in any trigger or to keep information throughout the game, which is important, because the next type can not do this.

Local Variables:
These are variables that are used only in the trigger that they are defined in. Essentially these are for saving information throughout a trigger without it overlapping when the trigger fires again or another trigger tries to use the variable. Every time the trigger that uses them is finished the variable is destroyed and recycled for use in that trigger again.

Events

Events are the part of a trigger that causes it to run. There are a wide variety of events ranging from a specific game time or real time, all the way to a unit casting an ability or a unit dying. You can have multiple events in a trigger and it will run off of any of them. When you have an event firing off a unit, player, or some other type of object in game you can use Triggering X (triggering unit, triggering player) to get that specific unit or player that caused the event to happen. There are also other types of event responses, like Damaging Unit (used when the event is, a unit takes damage), I am going to create another tutorial later about event responses and more complex events, even adding events to a trigger.

Example
Events
 A unit Dies <-- this fires when any unit dies
 Map Initialization <-- this fires 1 time at the start of the map
 A player types OMG! as an exact match <-- this fires when a player types OMG!
Local Variables
Conditions
Actions

Conditions

Conditions are essentially a requirement that must be fulfilled before the actions can begin (IE an event is fired where a unit takes damage, but you have a condition that they are in a specific region, if they are not, the actions will not fire). These conditions can require many many different things, ranging from a requirement that a variable is equal to something specific all the way to a unit-type requirement. Conditions can also include Or/And conditions, an OR condition is a list of conditions requiring that 1 of the conditions listed is fulfilled, AND conditions require that all listed conditions are full filled just like a normal condition section of a trigger, but they can be used inside OR conditions

Example
Events
 Any unit takes damage
Local Variables
Conditions
 Owner of triggering unit (!=) Player 15 <--- this requires that the owner of the unit IS NOT player 15, or neutral hostile i believe, (!=) = not equal to, (==) = equal to, (<=) = less than or equal to, (>=) = greater than or equal to
 Or, any of the conditions are true <--- one of the conditions in this and all of the conditions not in this are required
  Damage Taken (>) 1.00
  BooleanVariable (==) true <--- this is a variable you set in another trigger
  And, all of the conditions are true <--- this requires that a set of conditions are true for this condition to be fulfilled
   Unit type of triggering unit (==) zergling
   Unit type of Damaging unit (!=) zergling
Actions
 Do something but who cares what it is right now.

basically, if the unit that takes damage is owned by a computer, and it fulfills any of the conditions in the or condition it can go on with it's actions, the or condition has a few conditions inside it that are viable answers, the damage is greater than or equal to 1, a boolean variable is set to true, or the damage source is not a zergling and the triggering unit is

Actions

Actions, to be put as basically as possible, do something. Each of them does. An action is a reaction to the event, doing whatever it is that you want them to do. When in a trigger, they complete each action in an order, from top to bottom, but sometimes that order will not matter. If you have an action that moves a unit when it enters a region then right after you set a variable to that units position it would be different than if you set the units position before it was moved, but if you set a unit variable to that unit when it enters, then move it, it would be the same as though you had set it after you moved it because that unit has not been changed in the move.

Example
Events
 Any unit enters Region 1
Local Variables
 Point < no point >
 Unit < no unit >
Conditions
Actions
 Here is where the action's orders matter.
  Set Point = position of triggering unit
  Unit - Move triggering unit to the center of Region 2
 OR...
  Unit - Move triggering unit to the center of Region 2
  Set Point = position of triggering unit
 Each of those do different things, but below does not matter what order they are in.
  Set Unit = Triggering unit
  Unit - Move triggering unit to the center of Region 2

Any questions on this just pm me or make a post in the SC2 Galaxy Editor thread. I plan to add some pictures to this later, but until then, go out and create!

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