April 12, 2017 at 8:53 am #71822
here’s a getting started with Lua topic- online videos and manuals help
a bit but don’t deal directly with things you want to do in Ctrlr.
i have managed to get a couple of methods working, by copying and modifying
what i’ve seen in examples, and getting help from other forum users – that
was encouraging, but i still don’t really understand much. i don’t expect
to build really complex things at this stage, but it would be useful to go
through principles and simple examples.
as a test, i tried to make something simple: a button that
turns on a LED. i know i can do that with ‘Link to Modulator’, and
tested my image to check it’s working and that i’ve loaded it correctly.
it seemed like it would be simple, but it isn’t working, so i want to
go through step by step.April 13, 2017 at 7:18 am #71824
i’ll illustrate this better: here is a method that works, for
showing/hiding a modulator with a button, using setVisible()
setVisible3 = function(mod, value)
button = panel:getModulatorByName(“LED button”):getValue()
item = panel:getModulatorByName(“LED”)
button == 0 then
i don’t know how to send ‘give a value to…’…i’ve seen
setValue, so i’ve tried that, different ways: trying to
give the modulator a numerical value, or a bools state.
i need a run-through on this, i did not understand the
replies i got previously – this, for instance does NOT work:
setValue1 = function (mod,value)
button = panel:getModulatorByName(“LED button”)
item = panel:getModulatorByName(“LED”)
button:getValue() == 0 then
button:getValue() == 1 then
———————————————————–April 13, 2017 at 7:24 am #71825
btw: 2nd one: i know i’ve done ‘getModulatorByName()’ twice there;
i’ve tried it just using those names ‘button’ and ‘item’ as well.
same problem: i don’t know what i’m supposed to have there, or
what each element is doing.
all this is supposed to do is, when you toggle the button, the
LED goes on/off. ie: sending a value, or state, instead of the
show/hide function.April 13, 2017 at 4:04 pm #71829
I’m a beginner.
I’m fluent in multiple languages.
Now my question is, where do you write that code 🙂
And i guess a modulator is anything you put on the panel, right?April 13, 2017 at 10:26 pm #71831
you write methods in the Lua editor:
get to this via Panel>Lua editor or call up methods
on several parameters on the properties panel – create/edit
new methods using ‘add’.
everything seems to be called ‘modulator’ – even groups.
so what is ‘Component’?
ie: getComponent() vs getModulator()April 16, 2017 at 3:05 am #71845
This is what I can tell so far:
The objects you can add to the panel are called components.
Right-click on the panel and you will get an ‘Add component’ dialog.
A component’s properties are divided into multiple sections such as ‘Modulator’, ‘MIDI’, ‘Component generic’ and ‘Component’.
Yes components have a property section called component. :-).
Now here is the weird part. All components have a modulator property but you can only view a ‘modulator list’. You might think that modulators are a property of the components but wait, when you’re at the ‘modulator list’ window, click the ‘View’ menu item and select ‘Switch to Tree’. Now in the tree view you will see the objects you’ve added to the panel, the ones we thought were components are listed as ‘modulator’ and under those modulators listed are ‘MIDI’ and ‘Component’ 😀
WOW What’s going on??? Nothing is what it seems… 🙂
I think the tree is the best place to understand what really is going on.
So it seems that you are actually not adding components to the panel (even though that’s what the dialog says) but you’re adding an object called a modulator, which has a group of properties called a ‘component’, ‘MIDI’ and also another group of properties called, wait for it… a ‘modulator’. 🙂
You can confirm this. Add an object to the panel, select it, in it’s properties dialog look at ‘Modulator’ property group, you will see a property called ‘Link to what type of MODULATOR property’ click its associated drop-down list and you will see the 3 selection options, which are ‘Modulator’, ‘Component’, ‘MIDI Message’. This also tells me that modulator is a modulator property. 🙂 ‘Component’ seems to be a graphical sub-object of a modulator object. In the tree list, it almost seems like you should be able to delete, cut, copy, add or paste a component (or midi) object to a modulator object but it doesn’t work like that. Maybe in a future version…
So in consideration of all these information i think, the property groups such as component and midi are actually midi object and component object added to a modulator object and all those three objects have their own properties. So in theory, since the only object added to the panel is a modulator and since there is no add modulator function and you can not add a modulator without a component, it might make sense to have a dialog that says ‘add component’ since it will actually add a modulator object but then add the selected component (together with a midi object) to that modulator object.
Anyways, the next thing i was able to figure out is that the Modulator property group of a modulator object is where you link a Lua code or function to that Modulator object to do different things or behave in different ways.
So what is an expression and a method and what is the difference?
As far as i can tell, methods are names of files that hold functions written in lua code. You can see/list these when you open menu item ‘Panel’->’Lua Editor’
It seems like the convention is to have one function per method and both having the same name. Meaning, if you make function called splitBytes you will have a method called splitBytes and in that method you will have a function called splitBytes. This again seems like having the same mentality as having a modulator parameter of a modulator object but it’s probably how ctrlr uses lua… seems a bit strange to me. I mean why not have a single file that holds all the lua functions so you won’t have to call them ‘methods’ and you wont have to keep them in separate files too???
Probably this will make sense to me when i learn more about lua and how its used in ctrlr. Anyways, these methods can be called from the following three properties of a modulator object:
1.’Called to calculate the MIDI value to send’,
2.’Called to calculate new modulator value from a MIDI value’,
3.’Called when the modulator value changes’
And also methods could be called from 17 properties of the panel (+5 in editor section).
The next thing is expressions. Here is a list of expressions:
http://ctrlr.org/expressions-in-ctrlr-2/ they are little functions. Ctrlr is based on Juce (www.juce.com) and these expressions are a Juce class. They are different from lua code. The juce documentation explains it in the following way:
[A class for dynamically evaluating simple numeric expressions.
This class can parse a simple C-style string expression involving floating point numbers, named symbols and functions. The basic arithmetic operations of +, -, *, / are supported, as well as parentheses, and any alphanumeric identifiers are assumed to be named symbols which will be resolved when the expression is evaluated.]
In ctrlr they are only entered into 3 specific properties of a modulator object:
1.’Expression to evaluate when calculating the midi message value from the madulator value’,
2.’Expression to evaluate when calculating the modulator value from the midi message value’,
3.” (the third parameter does not have a name and i have no idea what it is, maybe it’s similar to the third property about methods).
Another concept is global vaiables and local variables which i have not figured out yet. Maybe someone else can post here about those 🙂
hope this helps someone.April 16, 2017 at 7:53 am #71849
the way i understand it/conceive of it:
a ‘modulator’ is any ‘object’ you can create on the workspace.
(i’m a bit cagey about using the term ‘object’ in case it has
another meaning in programming), and it is like a generic container
that gives an ID with a name and has ‘properties'(parameters).
ie: you can create a button, a slider, a UIgroup, a UItabs, etc.
and they will all be called ‘modulator’ initially (until you
attribute names to them)
within this generic ‘object’, there subsections in the properties
list: ‘modulator’, ‘midi’, ‘component generic’, ‘component’.
‘modulator’ is where the object (correct term: ‘modulator’) is
defined by name and vst index number. you can ‘link’ to another
modulator and property (ie: ‘value’), define actual(midi) value
vs. displayed value (ie: if you need to show -7<0>+7 range, but
midi value is 0-14, you use ‘expression to evaluate when calculating
midi message from modulator view’, and the entry will be:
‘modulatorValue-7’ eg: offset -7 )
and this is where you find the main Lua/method entry:
‘called when value changes’. if you want something to happen
when you change any onscreen control, you can create/add a
method here that is triggered when there is a value-change
there are 2 lua/method entries before this: one is for
panel-to-MIDI send, and the other is MIDI-to-panel receive
i’m concentrating on the value-change lua entry for the time
being. ie: adding functionality to onscreen controls/events.
the next section is ‘MIDI’ – simplest use is first to select
‘midi message type'(sysex/midi cc/etc.).
if you are using sysex, there’s a sysex message box where you
enter the entire sysex string including F0,etc.header and F7 end.
the value variable is represented by ‘xx’, and checksum is ‘zn’,
where ‘n’ is the number af bytes that need to be checksummed,
ie: usually address bytes plus value byte/s
-so if you have a 3-byte address, and a 1-byte value, you use ‘z4’
for the checksum byte (3+1).
you can disable this and use your lua method to send the sysex
string if you need an unconventional value order, and use the lua
to govern what gets sent. (then, the format for sysex/hex values
after MIDI, you’ve got 2 sections called ‘component’:
‘component generic’ are basic parameters for the type of component
-including *note* another name entry. this is the name displayed.
i tend to just make this the same as the ‘modulator’ name unless
there’s a name/title display issue.
‘component’, which defines colours, value range etc
that’s broadly it. you get confused between the 2 component
sections because you’re always scrolling up/down, and entries
are not always in the same order – but you do get used to it.
i never touch a lot of the entries, don’t use them. you will
discover what you need to use every time when you start creating
and defining ‘modulators'(the term to use for ‘objects’).
HOWEVER, the term ‘component’ comes back when you start writing
methods: expressions can be ie: ‘getModulatorByName()’ or
‘getComponent()’. i have just realised this, so i’m not sure
what the distinction is yet.April 16, 2017 at 7:58 am #71850
so, to create a new lua method for example, with an empty workspace,
create a eg: slider, then go to ‘called when the modulator value changes’:
the selection box shows ‘none’. click ‘add new’ and give your method a name.
now select it on the dropdown list. now click ‘edit selected method’, and
your lua editor opens, with an empty lua template. you can also call up the
lua console, from the menu: panel>lua consoleApril 16, 2017 at 8:16 am #71851
i resolved my problem with the ‘setValue’ method mentioned above.
the version that works is:
(for switching on/off a led, with a button)
— Called when a modulator value changes
— @mod http://ctrlr.org/api/class_ctrlr_modulator.html
— @value new numeric value of the modulator
toggle_led3 = function(–[[ CtrlrModulator –]] mod, –[[ number –]] value, –[[ number –]] source)
led = panel:getModulatorByName(“LED”)
if value == 1 then
it does not work without ‘,false’ there. i need to look up
what that is for. this is about as simple as it gets.
i’ve declared the ‘LED’ modulator, and attributed its name
in the script as ‘led’. if the value(of the button) is equal
to 1, the led has value=1; if not, =0.
one difficulty is knowing how/where your code ties in to Ctrlr
parameters – it seems you get 2 types of error messages: if
your method has compiled successfully without errors but is
still wrong for hooking up to the panel parameter, you will
either get a syntax-related error message telling you what
line/s is the problem, or you just get a Callback Error,
when you activate the modulator calling the method/function.
using ‘setVisible()’ it was getComponent(). and using
‘setValue()’ i had to ‘getModulatorByName()’. still not
sure why/what/etc.April 16, 2017 at 8:22 am #71852
nb: Lua is case sensitive, do not use spaces in function names
(use ‘_’), and avoid capitals when declaring and giving local
i do not know the distinction between ‘local’ and ‘global’
i have some beginners’ confusion with terms such as ‘string’,
variable, ‘value’ vs. ‘num’, statements, arguments, operators,
etc. – ie: have not mastered ‘jargon’/terminology fluently yet.April 16, 2017 at 11:31 am #71853
d*mn, i’m so proud of that led.
i just keep clicking that button…
:o)April 16, 2017 at 12:00 pm #71854
ok, so i tried OR. 2 buttons and a led
mini-panel demo with lua here:
(any thoughts on how i can make a led from the Ctrlr
onboard UI stuff?)April 16, 2017 at 4:26 pm #71856
Hi human fly, just following in diagonal your long posts…
Seems you are learning programming, learning Lua and learning Ctrlr at the same time…
What are you trying to do?
I have now one week off and will attack the Step by step guide 2.0 (I know I said that since some time but sometimes I wish having 48 hrs a day).
The answer to a lot of your questions are in:
– lua.org web site
– Juce class index: https://www.juce.com/doc/classes
– Ctrlr code (end of .h files list the available functions and arguments) https://sourceforge.net/p/ctrlrv4/code/HEAD/tree/nightly/Source/
– the existing panels. For example for LEDs, look at my Pro2 panel. Take the image from your temp directory, use it in your panel with same frame size and copy the methods by securing also the assignments I’m doing with other methods).April 16, 2017 at 8:37 pm #71858
(that OR is wrong: i cheated and used ~= for a quick result,
but it doesn’t give a proper OR output)
hi Goodweather, yeah sorry, some long posts, and i’ve been a
bit all over the place trying to kick on to the next stage.
trying to get a bit more focused interpreting what i’m seeing
in lua methods. best description is that i’m trying to learn
a bit of programming using lua from within ctrlr which i’m
pretty familiar with now.
tbh, i find those references confusing..*the entire JUCE class
index*.. i will have another look. i will have a look at those
.h files but i’m not sure what i’m looking for.
and yes, of course i look at other panels. working examples have
been most useful so far.
for the led, yes, i can nick your led ! or make one -but then
i have to bundle it as a resource file with any panel file
i post as an example; i was wondering if any Ctrlr object
could be adapted to act as a led by itself, but it seems not.
i’m making logic gate luas today, just to get a bit of practice.
(curious how to combine them ..)April 16, 2017 at 8:40 pm #71859
this is very useful, thanks.April 17, 2017 at 12:52 am #71861
There is no need to be cagey about calling modulators or components objects. Juce is an object oriented framework. Ctrlr is based on Juce. Components are Juce graphical objects and Modulators are Ctrlr objects which contain graphical objects properly called components. An object is an instantiation of a class. In the case of components, when you add a graphical object in ctrlr, it’s actually an instance of the component class. That’s why they’re called objects. If you want, you can even call them an instance of a juce component class.
April 17, 2017 at 1:04 am #71864
- This reply was modified 4 months ago by Mr.ToR. Reason: added the tree image
…April 17, 2017 at 5:35 am #71866
yeah, good. i don’t think there’s a problem conceiving of the
‘modulator’ as a kind of container created for each component
added, and having some properties/parameters. such name, vst
eg: you add a ‘component’, and the modulator is created for it
i haven’t tried ‘replace with’ yet, within the Add Component
dialog, but that should bear this out: once you’ve created
a modulator-with-component object, you can/could swap out the
component type for another, eg: change a slider to a button,
and still keep the same modulator number and properties.April 17, 2017 at 5:58 am #71867
i have not found a use for Tree view yet. but Modulator List
is very useful. (you have to be careful what you edit in there,
especially the Group and Tab columns, because you can really
mess up a project – best to edit those in the properties pane,
to be sure of what you’re doing)
i’m reasonably clear on the modulator/component hierarchy.
it is seeing both referred to in lua(‘in methods’?’in scripts’?etc.?)
and i have a notion that these two are different:
but i’m going to study the .h files Goodweather pointed to,
because there seem to be more items/commands than listed on that
expressions page. (just had a quick skim read so far )
this, after seeing what people have used in panels, thinking
‘where did they get that from?’, where’s the list of all those
functions you can use? – properly called? classes?
ha, you see, it is a first for me, looking at one of those .h
files, looking for something specific. didn’t know you could
do that.April 17, 2017 at 7:40 am #71868
here’s a (‘prefab’?) little panel with the basic logic gates.
just messing around with buttons and leds.
(hope you’re enjoying my crappy led graphic, included in zip
– Ctrlr could do with an onboard ‘led’ component, would look
really nice, being able to adjust colour and opacity – if it’s
not too much of a cpu-hit. vector graphics are cool.)
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