Controlling sketch variables with a Midi Keyboard, Joypad or other HID
in
Library and Tool Development
•
3 years ago
So I wanted to start a discussion to get a feel if many people here use Midi keyboards or joysticks to adjust parameters in their sketches?
I have just been using themidibus library and a gamepad library to create a simple controller class for my M-Audio Oxygen 8 keyboard & Logitech Wireless Rumblepad 2, but this seems to be an area that might be better suited for a specialized library that could support several different types of keyboards. Is there something like this that already exists?
I've read a little about Open Sound Control, but it doesn't sound like this is what I'm talking about.
If there isn't a good alternative out there right now, I'd consider writing the library as it seems like it could be really useful. I'd need some help figuring out the correct mappings for various keyboards and controllers I don't own, though this would probably just be saved in a series of XML files so it's easy to update.
I'd also be interested in hearing other's use-cases for a library like this. One situation I can think of would be for VJing. Using something like the Mother library and writing simple sketches that bind their dynamic parameters and events to key presses and knobs, a VJ artist could queue up sketches and control them real time with the keyboard or joypad.
In this case however it would be important for the variables to not be bound to any particular key, knob, or slider, and it would be helpful if they could be dynamically assigned to their physical counterparts based on what two sketches are currently active.
This is just a snippet, but It could possibly work something like this:
Copy code
- void setup()
- {
- controllerLib = new VarController(this);
- }
- void controlChange()
- {
- spotLoc.set( controllerLib.getFloat( "Spot location on X axis", -1.0, 1.0 )
- , controllerLib.getFloat( "Spot location on Y axis", -1.0, 1.0 ) );
- spotRot = controllerLib.getInt( "Rotation", 0, 7 );
- }
- void controlEvent()
- {
- if ( controllerLib.isEvent( "Next Color Palette" ) ) nextPalette();
- else if( controllerLib.isEvent( "Previous Color Palette" ) ) prevPalette();
- }
It could be fast enough to use strings if mapped a special way:
I would call
controlEvent() and return false for every
isEvent()callback registering the event name and mapping it to it's call index. Because following this pattern the calls would always happen in the same order, when real events come in I could just call controlEvent() and return false in isEvent() incrementing a counter and only returning true when that counter is equal to the call index of the registered event.
I would do the same for
controlChange() in
getFloat() and
getInt(), registering the variable names and min/max values passed in to their call index.
This way, I don't have to do any string comparisons at run time and the library would know what each variable is called by an easily understandable description that could be passed to another connecting tool.
The only remaining question is how one would dynamically map the events and variables to knobs, keys and joypads. What I'm picturing here is a separate tool you can open, kind of like how the serial window works in arduino, that would list all the different available events and variables on one side and controllers on the other side. Then the user could drag arrows to map keyboard notes to events and sliders/knobs to variables.
Any other thoughts / ideas?
Jack
