[Spell] Valid Backstab

[sentrywiz]

Hi all.

How would I make a valid backstab? I tried with facing of target of ability unit, but I don't really know enough trigonometry and angles to make it. I know its sinus cosine something.

 

[chobibo]

function IsAttackBackstab takes unit attacker, unit victim returns boolean
    local real x1=GetUnitX(victim)
    local real y1=GetUnitY(victim)
   
    local real x2=GetUnitX(attacker)
    local real y2=GetUnitY(attacker)
   
    local real victimFacing=GetUnitFacing(victim)*bj_DEGTORAD
    local real attackAngle=Atan2(y2-y1,x2-x1)
   
    set attackAngle=Acos(Cos(attackAngle-victimFacing))
   
    return (attackAngle*bj_RADTODEG)>120
endfunction

Dunno why it works though, I already forgot.

 

[deathismyfriend]

An easier way is to get facing angle of unit and then add 180 to it. That new facing will be in the back of the unit.

 

[sentrywiz]

function IsAttackBackstab takes unit attacker, unit victim returns boolean
    local real x1=GetUnitX(victim)
    local real y1=GetUnitY(victim)
   
    local real x2=GetUnitX(attacker)
    local real y2=GetUnitY(attacker)
   
    local real victimFacing=GetUnitFacing(victim)*bj_DEGTORAD
    local real attackAngle=Atan2(y2-y1,x2-x1)
   
    set attackAngle=Acos(Cos(attackAngle-victimFacing))
   
    return (attackAngle*bj_RADTODEG)>120
endfunction

Dunno why it works though, I already forgot.

GUI would be better since I don't know how to implement this with a spell.

An easier way is to get facing angle of unit and then add 180 to it. That new facing will be in the back of the unit.

Mind giving me a trigger?

 

[deathismyfriend]

I can't give you a trigger atm.

You do set realVariable = unit - get facing action.
Then realVariable + 180.
Then set unit facing to realVariable.

 

[sentrywiz]

I can't give you a trigger atm.

You do set realVariable = unit - get facing action.
Then realVariable + 180.
Then set unit facing to realVariable.

I think you misunderstand me. I don't want to backstab a unit, I want a condition to check if a unit is standing behind another unit when he casts the spell.

 

[Talavaj]

You only really have to check the facing of the units, for a unit to be behind a unit it needs to have the same or similar facing angle, + 180 would be for units that face each other.
Location does not matter, because unless the unit is already behind the target it would have to face it returning false.

 

[sentrywiz]

You only really have to check the facing of the units, for a unit to be behind a unit it needs to have the same or similar facing angle, + 180 would be for units that face each other.
Location does not matter, because unless the unit is already behind the target it would have to face it returning false.

I know its simple enough, countless maps have it. But its complex enough for me to not be able to trigger it.

So can you give me a trigger with just the condition checking if the casting unit is behind the target of ability unit?

 

[Talavaj]

Just do an and>real condition like.

• ((Facing of (Target unit of ability being cast)) Less than or equal to ((Facing of (Casting unit)) + 25.00)) and ((Facing of (Target unit of ability being cast)) Greater than or equal to ((Facing of (Casting unit)) - 25.00))

In GUI that should be enough.

 

[deathismyfriend]

Never use casting unit. Use triggering unit instead.
Also anything used twice or more should be stored in a variable and the variable should be used.
Both fixes are for speed / efficiency.

The above will work.

 

[jonhysone]

Well this needs a little bit knowledge of Angle Maths
A Unit is behind a unit means the angle of the backstabbing unit should be lesser than (Back-stabbed Unit's Angle) - 125 and greater than (Back-stabbed Unit's Angle) + 125
So he definitely stands within angle between 125 and 275 according to the back-stabbed unit's angle. I tried it once so it must work
NOTE: What I mean by 'Target Unit' is (Target Unit of Ability Being Cast)
NOTE 2: Store the more-than-twice used values in variables, you know what I mean.
Here is the condition :

• Conditions
  • If And/All conditions are true
    • (Facing Angle of (Triggering Unit)) Greater than ( (Facing Angle of (Target Unit)) + 125 )
    • (Facing Angle of (Triggering Unit)) Lesser than ( (Facing Angle of (Target Unit)) + 275)

@Talavaj :
This one detects all nearby units but front ones. In other words, it detects units who are right-side and left-side too. So instead of using 25 use 125 it only detects backside units.

• ((Facing of (Target unit of ability being cast)) Less than or equal to ((Facing of (Casting unit)) + 25.00)) and ((Facing of (Target unit of ability being cast)) Greater than or equal to ((Facing of (Casting unit)) - 25.00))

 

[Tal'Rarity]

Comparing the angles might work best. . . Since you already got some answers I shall provide you with another answer. =)

This is an example of using a damage detection for a passive backstab.
[trigger=ex.]
Events
Game - damageEventTrigger becomes Equal to 1.00
Conditions
Actions
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
damageType Equal to PHYSICAL
Then - Actions
-------- Actions for PHYSICAL damage --------
Set backstabunit1 = source
Set backstabunit2 = target
Set p = (Position of backstabunit1)
Set p2 = (Position of backstabunit2)
Set r1 = (Angle from p to p2)
Set r2 = (Facing of backstabunit2)
Set r3 = (Cos((r1 - r2)))
If (All Conditions are True) then do (Then Actions) else do (Else Actions)
If - Conditions
r3 Greater than 0.00
Then - Actions
Special Effect - Create a special effect attached to the chest of backstabunit2 using Objects\Spawnmodels\Human\HumanLargeDeathExplode\HumanLargeDeathExplode.mdl
Special Effect - Destroy (Last created special effect)
Else - Actions
Set backstabunit1 = No unit
Set backstabunit2 = No unit
Custom script: call RemoveLocation(udg_p)
Custom script: call RemoveLocation(udg_p2)
Game - Display to (All players) for 10.00 seconds the text: ((Name of source) + ( damages + ((Name of target) + ( with damage: + (|cffff0000 + (String(amount)))))))
-------- End of Actions for PHYISCAL damage --------
Else - Actions
[/trigger]

Yeah it works as well, hope I helped since this according to your first post was using something similar to this. I am somewhat sure chobibo gave you the JASS version of this though his uses 120 as the final detection so I don't know.

 

[Talavaj]

@jonhysone
I don't think that would work.

Keep in mind that real facing angle +/- value will result in degrees below/above 0~360 which will cause accuracy errors if unit is facing angles around 0/360 deg.
My example is very very crude, it wouldn't work if the units are facing 1 and 360 degrees for example.

 

[sentrywiz]

Thanks for all of your inputs.

+rep to Talavaj, jonhysone, Dat-C3.

I'll check all of your answers and try them all out. I'll see what works best for me.

 

[Vinz]

Keep in mind that real facing angle +/- value will result in degrees below/above 0~360 which will cause accuracy errors if unit is facing angles around 0/360 deg.

Check if angle > 180, then subtract 360. If it is negative reverse it to positive.

 

[jonhysone]

Well bro I've mistaken something as my mate mentioned above , thus I've attached a sample map to check a valid backstab.

It now works and checks if the backstab is valid. Once you move the unit with a different angle it won't show a valid backstab.

 

[sentrywiz]

Well I needed backstab for a spell, not when an attack happens. But still good to know!

 

[jonhysone]

Well I needed backstab for a spell, not when an attack happens. But still good to know!

Yep I do know. Like the one rikimaru has, it detects when it's attacked.

You just copy the actions I included in the map and paste them in your spell, and add damage if it goes true.

 

[Vinz]

and add damage if it goes true, then damage.

Doesn't that double up?

 

[jonhysone]

Doesn't that double up?

I didn't notice my self using a previous condition xD