Tutorial How To Trigger Nether Swap

[Fulla]

Nether Swap​

​

Instantly swaps location with target unit:

Intro
This is a very basic and simplistic spell, which makes it ideal for starting out with jass.
This tutorial does not cover the introduction to jass but rather goes straight into making a spell.
It also has a brief introduction to the Channel ability

Starters
Firstly go into the object editor and create a nether swap ability.
I recommend basing it of Channel, which is found under Neutral Hostile> Hero Abilities

Here is a screenshot to show how you should modify it

1 & 2 - These are the special effects that will be added to Caster and Target, I chose Blink, its up to you.
3 - Make sure you have the same options.
> Disable other abilities = false
> Follow Through Time = 0.00
> Options = Visible
> Target Type = Unit

Next we need to create the trigger
Go into the Trigger Editor and create a trigger called: Nether Swap
Please Note: NOT NetherSwap or nether swap etc.but Nether Swap

Should look like this:

Next you need to converted it to custom script:

For now we will skip the Conditions/Actions bit as this is quite boring, Once weve made a few spells I'll explain this to you
So Ill give you a base code to copy paste.

This is what you should currently have:

Copy Paste this:

function Trig_Nether_Swap_Conditions takes nothing returns boolean
    return GetSpellAbilityId() == 'A00P'
endfunction

function Trig_Nether_Swap_Actions takes nothing returns nothing
    
endfunction

//===========================================================================
function InitTrig_Nether_Swap takes nothing returns nothing
    set gg_trg_Nether_Swap = CreateTrigger()
    call TriggerRegisterAnyUnitEventBJ(gg_trg_Nether_Swap, EVENT_PLAYER_UNIT_SPELL_EFFECT)
    call TriggerAddCondition(gg_trg_Nether_Swap, Condition(function Trig_Nether_Swap_Conditions))
    call TriggerAddAction(gg_trg_Nether_Swap, function Trig_Nether_Swap_Actions)
endfunction

So now it should look like this:

Now we need to make sure the correct ability is in the condition.
For this go back into the Object Editor and click
View > Display Values as Raw Data

Next we need to get the raw data for the ability
In this case it is A000

Note: In your map if may differ so make sure to check.
Next go back into the trigger editor and lets alter the condition

Notice how Ive changed it to 'A000'

Ok we are now ready to start coding the spell

Method
This is how we will do the spell:
- Create a local to store: Casting Unit
- Create a local to store: Target Unit of Ability Being Cast Unit
- Create locals to store: Casting Unit's co-ordinates
- Create locals to store: Target Unit of Ability Being Cast's co-ordinates

- Move Casting Unit
- Move Target Unit of ability being cast

- Clean up leaks

Jass Code
The following code will go inside the Actions section:

Where the cursor is begin typing in there

Firstly we declare the locals

local unit c = GetTriggerUnit()
local unit t = GetSpellTargetUnit()

c = the Casting Unit
t = The Target Unit of ability being cast

Next we create locals for their co-ordinates

local real xc = GetUnitX(c)
local real yc = GetUnitY(c)
local real xt = GetUnitX(t)
local real yt = GetUnitY(t)

xc & yc = the co-ordinates of the Casting Unit
xt & yt = the co-ordinates of the Target Unit of ability being cast

Now we will set each unit's new position

call SetUnitX(c, xt)
call SetUnitY(c, yt)
call SetUnitX(t, xc)
call SetUnitY(t, yc)

This will place:
- Casting unit at co-ordinates stored for the Target Unit of ability being cast
- Target Unit of ability being cast at co-ordinates stored for the Casting Unit

Finally we clean up the leaks

set c = null
set t = null

This is overall how your code should look

function Trig_Nether_Swap_Conditions takes nothing returns boolean
    return GetSpellAbilityId() == 'A00P'
endfunction

function Trig_Nether_Swap_Actions takes nothing returns nothing
    local unit c = GetTriggerUnit()
    local unit t = GetSpellTargetUnit()
    local real xc = GetUnitX(c)
    local real yc = GetUnitY(c)
    local real xt = GetUnitX(t)
    local real yt = GetUnitY(t)
    call SetUnitX(c, xt)
    call SetUnitY(c, yt)
    call SetUnitX(t, xc)
    call SetUnitY(t, yc)
    set c = null
    set t = null
endfunction

//===========================================================================
function InitTrig_Nether_Swap takes nothing returns nothing
    set gg_trg_Nether_Swap = CreateTrigger()
    call TriggerRegisterAnyUnitEventBJ(gg_trg_Nether_Swap, EVENT_PLAYER_UNIT_SPELL_EFFECT)
    call TriggerAddCondition(gg_trg_Nether_Swap, Condition(function Trig_Nether_Swap_Conditions))
    call TriggerAddAction(gg_trg_Nether_Swap, function Trig_Nether_Swap_Actions)
endfunction

Your jass spell should now work, have fun and enjoy and stay tuned for more step by step mini jass tuts

thx
Fulla

 

[The Helper]

I like how you illustrated it. I like Tutorials that show step by step graphics of the process.

 

[Andrewgosu]

You don't have to declare so many variables and what about using "SetUnitPosition", which takes an unit and x, y coordinates as arguments?

function NetherSwap_Actions takes nothing returns nothing
    local unit caster = GetTriggerUnit()
    local unit target = GetSpellTargetUnit()
    local real x = GetUnitX(caster)
    local real y = GetUnitY(caster)
    //"Move instantly" the caster to the pos. of the target.
    call SetUnitPosition( caster, GetUnitX(target), GetUnitX(target) )
    //"Move instantly" the target to the pos. of the caster.
    call SetUnitPosition( target, x, y )
    
    set caster = null
    set target = null
endfunction

Anyway, enough of picking on your back, nice and simple tutorial for beginners.

 

[Fulla]

Yea I wanted to keep it real basic.
Any tips for improvement?

If it gets approved Id like to have a go at making a series of simple spell tutorials, to increase the interest in JASS.
Most Jass tut's Ive seen, tend to be a bit to advanced for the beginner.

 

[The Helper]

Make the Tutorials even if it does not get approved right away. Take advantage of the interest now because if you burn out you will never write them. You can always improve them with feedback here.