GetUnitsInLine

[Cheesy]

The title of this thread is a function I would like to write. However I have absolutely NO clue about HOW to do it. So I was hoping that one of you could either explain it to me directly, or point me in the direction of a tutorial that I could read to understand how to do this. I would prefer this to be in Jass, not GUI, and the only tutorial I could find that involved shapes such as lines and circles, was in GUI.

Thanks in advance,
CheesyBeefy

 

[Expelliarmus]

Well, hmm depends how you define a line?
a line from a wall, perpendicular to the caster
or a line from the caster to location y?

function GroupEnumUnitsInLine takes group g, real x1, real y1, real x2, real y2, real width returns nothing
    local real angle = Atan2(y2-y1,x2-x1)
    local real dist = SquareRoot( (x2-x1)*(x2-x1)+(y2-y1)*(y2-y1) )
    local real cdist = 0
    local group temp
    loop
        exitwhen (cdist > dist)
        set temp = CreateGroup()
        call GroupEnumUnitsInRange(temp,x1,y1,width/2,null)
        set bj_wantDestroyGroup = true
        call GroupAddGroup(temp,g)
        set x1 = x1+((width/4)*Cos(angle))
        set y1 = y1+((width/4)*Sin(angle))
        set cdist = cdist + (width/4)
    endloop
    set temp = null
endfunction

http://www.wc3jass.com/viewtopic.ph...ghlight=&sid=cf1aa7457ef2bce3ddfdcc79fa3ca1a7

 

[Cheesy]

I meant from Caster to Location Y. So you have something like this: (Horrible drawing)

C = Caster
U = A Unit
T = Target
_ = Units inside boundries

********************
***_________********
*C ---U--U--U--T****** etc...
***_________********
********************


So it would pick all of the units between the _'s and add them to a group, does that make sense?

 

[Genyuumaru]

Hmmm... There are 2 ways I can think of (It's faster for me to write em in GUI):

1:

set point1 = Position of Triggering unit.
set point2 = Target point of ability beeing cast.
Set angle = angle from point1 to point2
create 1 dummy unit for owner of triggering unit at point1 (dummy unit should be invisible and have locust).
custom script: call RemoveLocation (udg_point1)
custom script: call RemoveLocation (udg_point2)
set TempUnit = Last Created Unit

===========Variant a) - Known to spike when you cast the spell=========

For Integer A from 1 to X do
    local group tempgroup
    set point1 = Position of TempUnit
    set point2 = point1 offset by 10 towards angle
    Unit move TempUnit to point2
    custom script: call RemoveLocation (udg_point1)
    set tempgroup = Units within 75 of point2 matching XXX
    custom script: call RemoveLocation (udg_point2)
    pick every unit in tempgroup and do
    Actions
        For example: Cause Caster (needs a variable) to damage picked unit dealing x damage
    call DestroyGroup (tempgroup)
    set tempgroup = null
Remove TempUnit from the game

===========Variant b) - Known NOT to spike when you cast the spell, but will require arrays for MPI/MUI=========

Timer Start XTimer as a repeating timer that will expire in 0.02 seconds
Wait X seconds
Pause XTimer
Remove TempUnit from the game

//////////////////////////Another Trigger////////////////////////
Events: 
Timer XTimer expires
Actions: 
local group tempgroup
set point1 = Position of TempUnit
set point2 = point1 offset by 10 towards angle
Unit move TempUnit to point2
custom script: call RemoveLocation (udg_point1)
set tempgroup = Units within 75 of point2 matching XXX
custom script: call RemoveLocation (udg_point2)
pick every unit in tempgroup and do
Actions
  For example: Cause Caster (needs a variable) to damage picked unit dealing x damage
call DestroyGroup (tempgroup)
set tempgroup = null

2.
Needs a unit with an aura that has 75 AoE and works only on enemies (doesn't do anything).

local group tempgroup
set point1 = Position of Triggering unit.
set point2 = Target point of ability beeing cast.
Set angle = angle from point1 to point2
create 1 Aura unit for owner of triggering unit at point1 (Aura unit should be invisible and have locust/some aura).
custom script: call RemoveLocation (udg_point1)
custom script: call RemoveLocation (udg_point2)
set TempUnit = Last Created Unit
For Integer A from 1 to X do
    set point1 = Position of TempUnit
    set point2 = point1 offset by 10 towards angle
    Unit move TempUnit to point2
    custom script: call RemoveLocation (udg_point1)
    custom script: call RemoveLocation (udg_point2)
Remove TempUnit from the game
set tempgroup = Units Matching: Matching Unit has a buff "Aura Buff"
Unit Pick Every Unit in tempgroup and do
    Unit - Remove Aura Buff buff from picked unit
    For example: Unit cause caster to damage picked unit dealing X damage
call DestroyGroup (tempgroup)
set tempgroup = null

Hope I helped ^^

 

[Expelliarmus]

function GroupEnumUnitsInLine takes group g, real x1, real y1, real x2, real y2, real width returns nothing

local group g = CreateGroup()
local unit u = GetTriggerUnit()

//polar projection towards target point
local real xx = GetLocationX(GetSpellTargetLoc())
local real yy = GetLocationY(GetSpellTargetLoc())
local real angle = Atan2(yy - GetUnitY(u), xx - GetUnitX(u))
local real px = GetUnitX(u) + 170. * Cos(angle)
local real py = GetUnitY(u) + 170. * Sin(angle)

call GroupEnumUnitsInLine(g, GetUnitX(u), GetUnitY(u), px, py)
// ...
call DestroyGroup(g)
set g = null
set u = null

EDIT: Add width.. forgot it ^^

 

[Strilanc]

You shouldn't be using any trigonometry to do this. It's purely a vector problem.

//u = vector from caster to target point
set ux = targetX-casterX
set uy = targetY-casterY
//p = u rotated 90 degrees counter clockwise
set px = -uy
set py = ux
//v = vector from caster to unit
set vx = unitX-casterX
set vy = unitY-casterY
//r = normalized scalar projection of v onto u
set r = (vx*ux+vy*uy) / SquareRoot(vx*vx + vy*vy)  / SquareRoot(ux*ux + uy*uy)
//s = scalar projection of v onto p
set s = (vx*px+vy*py) / SquareRoot(vx*vx + vy*vy)

r is the distance along the line from caster to target, with 0 = caster, 1 = target

s is the signed distance from the line
if s > 0, the unit is to the left [counter clockwise]
if s < 0, the unit is to the right [clockwise]
if |s| is small, then the unit is close to the line
if |s| is large, then the unit is far from the line. probably missed.

A unit is 'hit' if s is between -width and width, and r is between 0 and 1.

 

[AceHart]

function ReturnTrue takes nothing returns boolean
	return true
endfunction

function UnitsBetweenPoints takes real x1,real y1, real x2,real y2, real distance returns group
    local real cx = (x1 + x2) / 2
    local real cy = (y1 + y2) / 2
    local real a = y2 - y1
    local real b = x1 - x2
    local real c = -b * y1 - a * x1
    local real d
    local unit u
    local group g = CreateGroup()
    local group result = CreateGroup()

    if distance == 0 then
        set distance = 100.0
    endif
    set distance = distance * SquareRoot(a * a + b * b)
    call GroupEnumUnitsInRange(g, cx, cy, SquareRoot((cx - x1) * (cx - x1) + (cy - y1) * (cy - y1)), Condition(function ReturnTrue))
    loop
        set u = FirstOfGroup(g)
        exitwhen u == null
        call GroupRemoveUnit(g, u)
        set d = a * GetUnitX(u) + b * GetUnitY(u) + c
        if d >= -distance and d <= distance then
            call GroupAddUnit(result,u)
        endif
    endloop

    call DestroyGroup(g)
    set g = null
    call GroupRemoveUnit(result, whichUnit)
    return result
endfunction

 

[Strilanc]

AceHeart, you should be using the enum units in rect function [look at what GroupEnumUnitsInRange() does and you will understand].

 

[Forty]

AceHeart, you should be using the enum units in rect function [look at what GroupEnumUnitsInRange() does and you will understand].

GroupEnumUnitsInRange is a native function, so it would be a bit strange if AceHeart could look what it does

 

[Flare]

AceHeart, you should be using the enum units in rect function

Aren't rects only rectangular/square shape, so if you wanted to enum units in a line towards a 45 degree angle, wouldn't it screw up?

 

[T.s.e]

Not if you create tons of parallell rects with an increasing MaxX, MaxY, MinX, MinY and add them to a region in the end. Or you could just use Breath of Frost and detect if it has the buff.

 

[Cheesy]

I prefer AceHart's solution, thanks and +Rep. :thup:

EDIT: Have to spread around, sorry.

 

[Strilanc]

GroupEnumUnitsInRange is a native function, so it would be a bit strange if AceHeart could look what it does

If you read the post carefully, you will see I told him to look at a different, non-native function.