Ball Bouncing off a Wall

[Derdan]

1) How do I make the ball face a certain direction instantly without moving in a semicircle in order to face that direction? I tried setting the turn rate to 9999 and made the movement speed 0, but to no avail.

2) I want the ball to bounce off the wall at the same angle at which it came in. How do you do this? The walls are placed sometimes in a circle around a point or in straight lines.

Thanks.

 

[Shoto]

1)

• Actions
  • Unit - Make (Unit) face (Center of (Playable map area)) over 0.00 seconds
  • Unit - Make (Unit) face Degrees over 0.00 seconds
  • Unit - Make (Unit) face (Unit) over 0.00 seconds

There are a few options.

 

[Derdan]

1)

• Actions
  • Unit - Make (Unit) face (Center of (Playable map area)) over 0.00 seconds
  • Unit - Make (Unit) face Degrees over 0.00 seconds
  • Unit - Make (Unit) face (Unit) over 0.00 seconds

There are a few options.

The unit still curves to turn :\

 

[ap0calypse]

I believe you can't make a unit change their facing instantly. There was some minimum to this (I think it was about 0.7 seconds, but this may be incorrect).
Because of this, you absolutely need a variable for the angle, you cannot use the unit's facing.

To make it bounce, this is a fairly simple pseudocode:

set angle = 360º - angle
set new loc = loc with offset

if not IsPathable(new loc) then
    set angle = angle + 180º
    set angle = angle % 360º
    set new loc = loc with offset

    if not IsPathable(new loc) then
        set angle = 360º - angle
        set new loc = loc with offset
    endif
endif

With "angle % 360" being the modulo-operator (it also exists in GUI).

Picture Example

 

[Derdan]

Hmm... so why doesn't this work? (The unit never changes directions).

• Speed
  • Events
    • Time - Every 0.05 seconds of game time
  • Conditions
  • Actions
    • Set ballgroup = (Units of type Ball)
    • Unit Group - Pick every unit in bulletgroup and do (Actions)
      • Loop - Actions
        • Set unit = (Picked unit)
        • Set angle = (Facing of unit)
        • Set loc1 = (Position of unit)
        • Set loc2 = (loc1 offset by 10.00 towards angle degrees)
        • Unit - Move unit instantly to loc2
        • Set towergroup = (Units within 88.00 of loc2 matching ((Unit-type of (Matching unit)) Equal to Scout Tower))
        • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
          • If - Conditions
            • (Number of units in towergroup) Greater than 0
          • Then - Actions
            • Set angle = (360.00 - angle)
            • Set loc1 = (Position of unit)
            • Set loc2 = (loc1 offset by 10.00 towards angle degrees)
            • Set towergroup = (Units within 88.00 of loc2 matching ((Unit-type of (Matching unit)) Equal to Scout Tower))
            • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
              • If - Conditions
                • (Number of units in towergroup) Greater than 0
              • Then - Actions
                • Set angle = (180.00 + angle)
                • Set angle = (angle mod 360.00)
                • Set loc1 = (Position of unit)
                • Set loc2 = (loc1 offset by 10.00 towards angle degrees)
                • Set towergroup = (Units within 88.00 of loc2 matching ((Unit-type of (Matching unit)) Equal to Scout Tower))
                • If (All Conditions are True) then do (Then Actions) else do (Else Actions)
                  • If - Conditions
                    • (Number of units in towergroup) Greater than 0
                  • Then - Actions
                    • Set angle = (360.00 - angle)
                    • Set loc1 = (Position of unit)
                    • Set loc2 = (loc1 offset by 10.00 towards angle degrees)
                    • Unit - Move unit instantly to loc2
                  • Else - Actions
              • Else - Actions
                • Unit - Move unit instantly to loc2
          • Else - Actions
            • Unit - Move unit instantly to loc2
    • Custom script: call DestroyGroup( udg_towergroup )
    • Custom script: call DestroyGroup( udg_ballgroup )
    • Custom script: call RemoveLocation( udg_loc2 )
    • Custom script: call RemoveLocation( udg_loc1 )

 

[ap0calypse]

Please note that setting all those variables again will leak.
So worst-case scenario, you've got 8 leaks every time the trigger runs.

To get the terrain pathability, I use this function (don't worry about it being JASS, it's just to make it easier):

function IsPathable takes real x, real y returns boolean
    call SetItemPosition(udg_Item, x, y)
    
    if GetItemX(udg_Item) == x and GetItemY(udg_Item) == y then
        return true
    endif
    return false
endfunction

It returns true if you can move there, and false if you cannot.
There won't be any need for a unit group if you use this.

Test-map attached.

 

[Derdan]

Wow, that works perfectly! This would be a good resource for anyone who needs a system like this!