Follow A Unit

01-08-2009, 11:35 PM

im trying to figure out the best way to get a unit to follow another unit without 'Amov'.

First way I tried was SetUnitFacing(follower, Angle Between Follower & Folowee) & PolarProjection(GetUnitFacing()...), but it's too easy to get stuck on trees and whatnot.

Next was making an invisible unit that is ordered to move to the folowee, then having the follower unit PolarProject to the angle between itself and the "pather" unit. This method proved to have really unpredictable pathing (thanks blizzard) and sometimes it would take downright retarded routes

anyone have any ideas?

01-09-2009, 12:23 AM	#2
Zerzax	I would suggest moving the follower yourself, using coordinates and angles as well as setting facing. You'd set the animation of the unit to walk via SetUnitAnimationByIndex, which is heavily dependent on the unit's model and it's walk animation index.

01-09-2009, 12:52 AM	#3
Ammorth	Why not use your second approach, but instead do: JASS: call SetUnitX(yourNoAmovUnit, GetUnitX(yourDummyPatherUnit)) call SetUnitY(yourNoAmovUnit, GetUnitY(yourDummyPatherUnit))

01-09-2009, 03:36 AM

Beardo

Quote:

Originally Posted by Ammorth

Why not use your second approach, but instead do:

JASS:

call SetUnitX(yourNoAmovUnit, GetUnitX(yourDummyPatherUnit))
call SetUnitY(yourNoAmovUnit, GetUnitY(yourDummyPatherUnit))

It's a good idea, but there's a few problems:

1. I can't get the pather unit to spawn EXACTLY where the follower is standing. I've messed with the collision, offset the X/Y by 1, and I still cant get it to spawn ontop of it 100% of the time.

2. Because the movement is all triggered, the "run speed" of the nonAmov unit is just the distance it gets polarprojected. So if I just set the X/Y to the postion of the pather, the run speed would be all fucked up

01-09-2009, 04:15 AM

Ammorth

Then use a breadcrumb technique.

pseudocode:

breadcrumb linkedlist crumbs // use a linked list here

function periodic
    local breadcrumb
    if ParentIsMoving then
        crumbs.addLast(newParentCrumb()) // basically storing the unit's position here
        call moveChildTo(crums.first)
        call crums.first.destroy()
    endif
endfunction

so if the parent moves, it lays crumbs and the child will only go to the next crumb when the parent lays a new crumb. The number of crumbs would allow you to provide a general follow distance (or delay in this case). If you want to improve performance, you can skip multiple crumbs and interpolate between 2 crumbs.

edit: think of this as a final fantasy follow routine (when the rest of your party follows behind the leader).

01-09-2009, 04:52 AM

Beardo

Quote:

Originally Posted by Ammorth

Then use a breadcrumb technique.

pseudocode:

breadcrumb linkedlist crumbs // use a linked list here

function periodic
    local breadcrumb
    if ParentIsMoving then
        crumbs.addLast(newParentCrumb()) // basically storing the unit's position here
        call moveChildTo(crums.first)
        call crums.first.destroy()
    endif
endfunction

I'm not sure how to use linked lists

But I'd personally just make a struct, have a timer calling a method that lays a crumb (stores the X/Y in 2 real arrays?) IF the pather is @ least someDistance (the runspeed amount) from the last crumb

is there anyway around using sqroute for the bolded part?

01-09-2009, 05:56 AM

Ammorth

JASS:

globals
    constant real YourDistance = 500.*500.
endglobals
//...
// in function
    set tempDist = (dx*dx)+(dy*dy) // dx/dy are the change in x/y (x2 - x1).
    if tempDist > YourDistance then // whatever you want

01-09-2009, 10:07 AM

Beardo

Quote:

Originally Posted by Ammorth

JASS:

globals
    constant real YourDistance = 500.*500.
endglobals
//...
// in function
    set tempDist = (dx*dx)+(dy*dy) // dx/dy are the change in x/y (x2 - x1).
    if tempDist > YourDistance then // whatever you want

you kind of lost me there. could you explain it differently please?

01-09-2009, 10:39 AM

Blackroot

Quote:

Originally Posted by Beardo

you kind of lost me there. could you explain it differently please?

Ammorth's function executes if the square of both distances is greater than the square of the max distance.

In other words, it's a spinoff of the pythagorean theorum. Building off ammorth here:

JASS:

globals
timer t
unit gpather
unit gleader
constant integer maxdist = 128*128
endglobals

function PatherHandler takes nothing returns nothing
 local real dx = GetUnitX(gpather) - GetUnitX(gleader)
 local real dy = GetUnitY(gpather) - GetUnitY(gleader)

 if(dx*dx + dy*dy > maxdist)then
  call SetUnitX(gpather, GetUnitX(gleader), GetUnitY(gleader)
 endif
endfunction

function EstablishPather takes unit pather, unit leader returns nothing
 set gpather = pather
 set gleader = leader
 call TimerStart(t, .05, true, function PatherHandler)
endfunction

What that would do is make it so every time pather gets 1 terrain square away it teleports it to the leaders position

01-09-2009, 07:49 PM	#10
Zerzax	I would use IsUnitInRangeXY or IsUnitInRange to prevent collision dist problems.