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Changing the Parameter maximum post-startup, how is it possible?

edited June 2012 in Questions Posts: 7

I take it this page does not exist?

The problem: 
I'm trying to make a certain parameter change its upper value dynamically
so that it always matches a number set by another parameter. 

My understanding is that when you put parameters in the setup function it will only 
setup the parameters once. 

Thus anything that should change a parameter's maximum after start up is thus ignored as it only goes there once.

Suffice it to say I've tried putting it in the draw function, the touch function, and a class init function (on separate occasions of coarse not all at once).

draw function results:
parameter gets set to 1 and can't be moved. 
Starting it with a 0 minimum? Makes 1 its maximum.

touch function results:
Starting it with a 0 minimum? Makes 1 its maximum unless you change the upper-limit parameter BEFORE YOU TAP THE SCREEN (caps for emphasis).

parameter maximum won't change beyond initial setup and some how values affected by it are loss gradually if you were to persistently tap outside the parameter/output section of the screen. 

init function results:
Starting it with a 0 minimum? Makes 1 its maximum unless you set it up in a separate class init  that's only accessed by way if special condition change the upper-limit parameter BEFORE YOU CHANGE THE PARAMETER (caps for emphasis).

However parameter maximum still won't change beyond the initial setup.

On a side-note I quite like the way you don't have to tap the screen to update everything  with it in the init function. 

I just wish there was some other way to get it to recognize that one parameter's upper-limit has changed


  • edited June 2012 Posts: 489

    Perhaps you could use clearParameters() then re-establish the same parameters with the settings you want? You are not constrained to calling these functions in setup().

  • Thanks for trying @mpilgrem but the results I posted earlier were not from setup they were from other locations. I thought I made that clear sorry for the confusion.

    As for clearParameters()? I've tried that too.

  • SimeonSimeon Admin Mod
    edited June 2012 Posts: 5,054

    @GenobiJuan parameters can only be set once, unless you call clearParameters (as @mpilgrem mentioned) and re-establish them. For example the following code will change the upper limit of "MyParameter"

    function setup()
        parameter( "MyParameter", 0, 50 )
    function draw()
    function touched( touch )
        if touch.tapCount == 1 and touch.state == ENDED then 
            parameter("MyParameter", 0, 100 )

    If you slide the parameter before you touch the screen, it will only reach 50. After tapping the screen it should be able to reach 100.

  • edited June 2012 Posts: 489

    You could redefine parameter(), iparameter() and clearParameters() to provide the functionality you seek.For example:

    -- Warning: Some browsers (eg IE9 for Windows) may not render all of -- the underscore characters in the code below. G has one in front of it. -- Version 2012. do -- Preserve built-in functions local oldP = parameter local oldIP = iparameter local oldCP = clearParameters local pList = {} -- Will hold the set i/parameters local pProp = {} -- Will hold their properties -- Private generic helper local addP = function(isIParam, var, min, max, init) local old = oldP if isIParam then if init then init = math.modf(init) end if min then min = math.modf(min) end if max then max = math.modf(max) end old = oldIP end if not min then min = 0 max = 1 if isIParam then max = 10 end -- Handle iparameter with no max end if not max then -- Handle case of two arguments max = math.max(0, min) min = 0 if isIParam then max = 10 end -- Handle iparameter with no max end if not pProp[var] then if not init then init = min end pProp[var] = { min = math.min(min, init), max = math.max(max, init), isIParam = isIParam} pList[#pList+1] = var old(var, min, max, init) return end local p = pProp local l = pList p[var] = { min = min, max = max, isIParam = isIParam} clearParameters() for i = 1, #l do local k = l[i] local v = p[k] local i = _G[k] if isIParam then i = math.modf(i) end if k == var and init then i = init end if v.isIParam then iparameter(k, v.min, v.max, i) else parameter(k, v.min, v.max, i) end end return end -- Redefine parameter() parameter = function (var, min, max, init) addP(false, var, min, max, init) end -- Redefine iparameter() iparameter = function (var, min, max, init) addP(true, var, min, max, init) end -- Redefine clearParameters() clearParameters = function () pProp = {} pList = {} oldCP() return end end -- Example of use function setup() parameter("test1", 0, 100, 50) iparameter("itest1", 0, 100, 50) parameter("test2", 100, 200, 50) iparameter("itest2", 100, 200, 50) parameter("test3") iparameter("itest3") end function draw() background(40, 40, 50) end function touched(touch) if touch.state == BEGAN then parameter("test2", 0, 300) -- Reset limits iparameter("test1", 0, 100) -- Change to an iparameter end end

    (Update) I've added a generic helper to reduce repetition. (Further update) Now correctly handles iparameter with no max, and case of two arguments.

  • Posts: 489

    In response to your opening comment about the wiki, @GenobiJuan, I have added pages, here and here, to extend what is documented in Codea's in-app reference.

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