UnitsInRange usage in struct

[Rllulium]

I have been fiddling with projectiles for a while, but it seems that no matter what I do I cannot get around the usage of GroupEnumUnitsInRange(), a static method and a global struct variable. So I am merely wondering if anyone knows of a more flexible implementation of the collision check? Thanks in advance.

library Collide uses Movement

globals
    private collide co
endglobals

struct collide extends movement
    real    radius   
    boolean continue = true
    
    stub method Impact takes unit u returns boolean
        return false
    endmethod
    
    static method Collision takes nothing returns boolean
        if HitCheck(GetFilterUnit(), co.which) then
            set co.continue = co.Impact(GetFilterUnit())
        endif
        return false
    endmethod
    
    method Action takes nothing returns boolean
        set co = this
        call GroupEnumUnitsInRange(FilterGroup, GetUnitX(.which), GetUnitY(.which), .radius, Filter(function thistype.Collision))
        set this = co
        return .continue
    endmethod
    
    static method create takes unit which, real angle, real range, real speed, real acc, real radius returns collide
        local thistype c = thistype.allocate(which, angle, range, speed, acc)
        set c.radius = radius
        return c
    endmethod
endstruct

 

[Lehona]

If you just use 2 global Unit-variables you won't have to create every time a new method...

 

[Rllulium]

If you just use 2 global Unit-variables you won't have to create every time a new method...

I'm not sure I follow you here. Besides, the point is that I shall be able to extend the struct, rewrite .Impact and therein use any members of the parent structs.

 

[Lehona]

Forget my post, it was an evil mix of misunderstanding and confusion.

 

[Jesus4Lyf]

You can use a dynamic trigger with the event: [LJASS]TriggerRegisterUnitInRange(trig, projectile, range, null)[/LJASS].
Attach the projectile to the trigger using a hashtable and gethandleid, or triggerexeccount if you're familiar with it and feel it's appropriate (it isn't, really).

Inside the event response (which should be done in the conditions, especially since it's a dynamic trigger) you may use [LJASS]GetTriggerUnit()[/LJASS] to get the unit the projectile is colliding with. You still will have to use a group to store which units have been hit, most likely, since spells like Blink exist (unless your projectile stops at first impact).

Hope that helps.

 

[Rllulium]

You can use a dynamic trigger with the event: [LJASS]TriggerRegisterUnitInRange(trig, projectile, range, null)[/LJASS].
Attach the projectile to the trigger using a hashtable and gethandleid, or triggerexeccount if you're familiar with it and feel it's appropriate (it isn't, really).

Inside the event response (which should be done in the conditions, especially since it's a dynamic trigger) you may use [LJASS]GetTriggerUnit()[/LJASS] to get the unit the projectile is colliding with. You still will have to use a group to store which units have been hit, most likely, since spells like Blink exist (unless your projectile stops at first impact).

Hope that helps.

Getting back to this, I was at first glad to see a rather simple solution, even thou I have in the past cursed the lack of a certain event response. It did however seem to be so that using [LJASS]TriggerRegisterUnitInRange()[/LJASS] with a fast projectile makes the collision rather inaccurate (Seems to be mentioned here aswell: http://www.thehelper.net/forums/showthread.php?t=145882 ).
Given the limited amount of units that can actually be struck by projectiles in my current map, I will probably try to detect collision on these targets rather than the projectile. In any case; thanks, I'd rep if I could.

EDIT: Doesn't [LJASS]null[/LJASS]ing a Boolexpr leak?

 

[Kenny]

I have just implemented [ljass]TriggerRegisterUnitInRange()[/ljass] into my projectile system and it works quite well.

If you are using projectile speeds above approximately 1500 units per second while having a collision radius of less than 100.00 then you may see some inaccuracy with this style of collision detection, however projectile speeds that fast are hardly needed in most maps and you can just raise the collision radius if needed.

> EDIT: Doesn't [LJASS]null[/LJASS]ing a Boolexpr leak?

No, not for trigger events. It use to for GroupEnum functions, but blizzard fixed that.

 

[Rllulium]

I have just implemented [ljass]TriggerRegisterUnitInRange()[/ljass] into my projectile system and it works quite well.

If you are using projectile speeds above approximately 1500 units per second while having a collision radius of less than 100.00 then you may see some inaccuracy with this style of collision detection, however projectile speeds that fast are hardly needed in most maps and you can just raise the collision radius if needed.

Well, that's my problem right there. I am using projectiles with speeds up to 2000 u/s with hitboxes ranging from 100-80. Also, the units that are to be struck by the projectiles may be moving as fast as 800 u/s in the opposite direction. Which leads to a large risk of the collision not occuring at all.