Damage enemies that contact a 'link' between two units.

[gusanomental]

Yes, like Io's Tether in Dota. How to check when an enemy crosses the link?

 

[Marine]

Yes, like Io's Tether in Dota. How to check when an enemy crosses the link?

We need more information. What is the link? A special effect?

 

[gusanomental]

What I mean is that I need to know how to check when an enemy unit steps between other two units. Just like this:

1-----2

3

1--3--2

 

[Wietlol]

If I understand it correctly, you have two units and a lightning in between them (a straight line).
If so, you could group all units inside a rectangle on that line and damage each unit in the group.

I dont know how you can group the units though.
Maybe Ill be making another group function.

 

[Nichilus]

An option would be to use math in this case. You can determine the distance of a point from line via various formulas.
First, you would need the formula for the line between the two units meaning you would need to create formula for line from two points (those two points = locations of both units).

Then you would need to pick all units, which are within [length of line /2] range from the center of the line.
Finally, iterate through each picked unit and check the distance of the unit from the line. If it is close enough for you (e.g. range 30 or less), that unit touched the line.

There are many tutorials on how to create a line from two points and how to determine the distance of a point from a line.

 

[Wietlol]

I would use something like 60 though.
Remember that Group Enumerations and GetUnitX() and GetUnitY() are both from the center while the regular targeting is calculated on collision size.
Ussually +30 would do.

 

[gusanomental]

Thanks for the help.

 

[RobertMKD]

Finally, iterate through each picked unit and check the distance of the unit from the line.

How do you check the distance from the line? 0_0

 

[Wietlol]

library IsPointInRectangle
    //determins if point P is in rectangle ABCD
    function IsPointInRectangle takes real ax, real ay, real bx, real by, real cx, real cy, real dx, real dy, real px, real py returns boolean
        local real cross0 = (py-ay)*(bx-ax)-(px-ax)*(by-ay)
        local real cross1 = (py-cy)*(ax-cx)-(px-cx)*(ay-cy)
        local real cross4 = (py-dy)*(ax-dx)-(px-dx)*(ay-dy)
        
        return ((cross0*cross1 >= 0) and (((py-by)*(cx-bx)-(px-bx)*(cy-by))*cross1 >= 0)) or ((cross0*cross4 >= 0) and (((py-by)*(dx-bx)-(px-bx)*(dy-by))*cross4 >= 0))
    endfunction
endlibrary

Might help.

All you have to figure out is what A, B, C and D are.