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IDProjectCategoryView StatusDate SubmittedLast Update
0001920Spring engineLuapublic2010-05-10 01:482010-05-10 17:01
Reporterdas bruce Assigned To 
PrioritynormalSeverityminorReproducibilityalways
Status closedResolutionno change required 
Product Version0.81.2 
Summary0001920: Turn command turns wrong way if unit doesn't move between orders
DescriptionI have a builder which is supposed to turn towards its target construction before being built, it does this fine the first time, but if it doesn't move between constructions it will turn the piece the opposite direction that it is supposed to.
Additional Information contains the script for the unit. turnHack is the variable I use to compensate for this odd behaviour.
Additional Informationlocal body, shovel, nanogun1, nano, nanogun2, nano2, dish = piece ("body", "shovel", "nanogun1", "nano", "nanogun2", "nano2", "dish")

--constants
local SIG_AIM = 2
local SIG_BUILD = 4
local RESTORE_DELAY = 2000
local rad = math.rad
local pi = math.pi

local TURNRATE = 2
local HEADING = 82

--Calls for Effects. If you get more effects just add SFX.CEG + 1, SFX.CEG + 2 and so on...
-- local orc_hand_glow = SFX.CEG
-- local orc_orange_glow = SFX.CEG +1

--includes
include "rockunit.lua"
include "smokeunit.lua"
include "include/dishspin.lua"

function script.Create(unitID)
    turnHack = 1
    StartThread(DishSpin(dish))
end

local function RestoreAfterDelay(unitID)
    -- Sleep(RESTORE_DELAY)
end

function script.StartBuilding(heading, pitch)
    Signal(SIG_BUILD)
    SetSignalMask(SIG_BUILD)
    originalHeading = GetUnitValue(HEADING)*pi/32768 --save the original heading
    
    Turn(body, y_axis, heading*turnHack, TURNRATE) --turn the base piece to face the construction (takes time)
    Turn(shovel, x_axis, rad(-10), TURNRATE)
    WaitForTurn(body, y_axis)
    
    Turn(body, y_axis, 0) --Rapidly flick back to the original heading and then
    Spring.SetUnitRotation(unitID, 0, -(originalHeading+heading), 0 )

    WaitForTurn(shovel, x_axis)
    SetUnitValue(COB.INBUILDSTANCE, 1)
    turnHack = -1
    return 1
end

function script.StopBuilding()
    Signal(SIG_BUILD)
    SetSignalMask(SIG_BUILD)
    SetUnitValue(COB.INBUILDSTANCE, 0)
    Turn(shovel, x_axis, 0, TURNRATE)
    return 0
end

function script.StartMoving()
    turnHack = 1
end
function script.StopMoving()
end

function script.QueryNanoPiece() return nanogun1 end

--Pieces that fly off when unit is destroyed. Other pieces disappear!
function script.Killed(recentDamage, maxHealth)
    return 1
end
TagsNo tags attached.
Checked infolog.txt for Errors

Activities

Kloot

2010-05-10 16:38

developer   ~0004901

Last edited: 2010-05-10 17:00

 There is nothing odd about it, you just don't seem to understand angles.

A). the heading argument passed to StartBuilding() is the relative signed difference between the unit's own heading and the heading toward the position of the to-be-built object.

B) Unit headings are represented with respect to a fixed coordinate system.

C). Turn() does not change the heading of the unit, just of the piece it is called on.

Assume the initial unit and body headings are 0 (--> due SOUTH), and the first buildee position is south-EAST of the unit (for a relative angular gap of +45 degrees). Therefore...

StartBuilding(heading = +45, irrelevant)
   1. originalHeading = GetUnitValue(HEADING) * pi/32768
   2. Turn(body, y_axis, heading, TURNRATE) [without hack]
   3. WaitForTurn(body, y_axis)
   4. Turn(body, y_axis, 0)
   5. Spring.SetUnitRotation(unitID, 0, -(originalHeading+heading), 0 )

...after [3] the unit's new heading is still originalHeading (0), but visually appears to be pointing in a different direction because the body piece has turned. [4] has no effect on the unit's heading either, it just resets the body piece orientation to 0. [5] then actually *does* change the heading (but *not* the piece orientations, which are relative to the unit) from 0 to -(0 + 45) = -45 to point the unit toward the first buildee.

Now assume the second buildee is due EAST, so StartBuilding is again called with heading = +45. The new <originalHeading> will be -45, and thus SetUnitRotation will now flip the heading to -(-45 + 45) = 0 degrees, changing it from south-EAST back to SOUTH which is the opposite of what you want.

Issue History

Date Modified Username Field Change
2010-05-10 01:48 das bruce New Issue
2010-05-10 16:38 Kloot Note Added: 0004901
2010-05-10 16:47 Kloot Note Edited: 0004901
2010-05-10 16:47 Kloot Note Edited: 0004901
2010-05-10 16:48 Kloot Status new => closed
2010-05-10 16:48 Kloot Resolution open => no change required
2010-05-10 17:00 Kloot Status closed => new
2010-05-10 17:00 Kloot Resolution no change required => reopened
2010-05-10 17:00 Kloot Note Edited: 0004901
2010-05-10 17:01 Kloot Status new => closed
2010-05-10 17:01 Kloot Resolution reopened => no change required