Broadcasters best practices

Christoph Hart

@Orvillain not really. A object factory creates a data structure with a densely packed memory layout that can be used for a neat implementation of MIDI logic, but it lacks most of the features that you would expect from a object-oriented class object (like methods or polymorphism).

What are you trying to achieve?

Orvillain

@Christoph-Hart said in Broadcasters best practices:

@Orvillain not really. A object factory creates a data structure with a densely packed memory layout that can be used for a neat implementation of MIDI logic, but it lacks most of the features that you would expect from a object-oriented class object (like methods or polymorphism).

What are you trying to achieve?

I'm mainly pondering what would be the cleanest way to create an object prototype and then instantiate however many of them I'd like - and each instance automatically creates the relevant DSP nodes, UI widgets, and various methods and callbacks required.

In Python you'd do something like:

class WhateverTheClassIsCalled(inheritance here)

def __init__(self, and then any initialisation arguments here)
    self.blah = blah

def do_a_thing(self, blahblahblah)
   thing_is_done = blahblahblah(bloo bloo bloo)
    return thing_is_done


for i in range(0, 32):
   instance_var = WhateverTheClassIsCalled(blahblahblah, bloloooooloooo)

That sort of thing. In Python it is fairly trivial to put together a class this way, and tbh, syntax aside it looks like the Factory Object approach might do the same sort of thing???

BTW - the above is probably the best code I've ever written. :face_with_tears_of_joy:

clevername27

@Orvillain One cool thing about namespaces is that each comes with 32 high-speed reg variables.

Christoph Hart

You can do this kind of simple object oriented stuff by creating a JSON object and attaching functions as member, which will then access the JSON properties through the this.property syntax:

// This as close as you'll get to object oriented programming in HISE Script
function createInstance(valueToUse)
{
    var prototype = {
        create: function()
        {
            // Access properties of the "class" object with this
            Console.print(this.value);
        },
        value: valueToUse // store the "constructor argument" as "class member"
    };
    
    return prototype;
}

// And now let's add polymorphism:
function createSubClassInstance(valueToUse)
{
    var prototype = createInstance(valueToUse);
    prototype.create = function()
    {
        Console.print(this.value + ": SUBCLASS");
    };
    
    return prototype;
}

// Create two instances of the "class"
var x1 = createInstance(90);
var x2 = createInstance(120);

var x3 = createSubClassInstance(500);

// call the method of each instance
x1.create();
x2.create();
x3.create();

Orvillain

@Christoph-Hart said in Broadcasters best practices:

You can do this kind of simple object oriented stuff by creating a JSON object and attaching functions as member, which will then access the JSON properties through the this.property syntax:

// This as close as you'll get to object oriented programming in HISE Script
function createInstance(valueToUse)
{
    var prototype = {
        create: function()
        {
            // Access properties of the "class" object with this
            Console.print(this.value);
        },
        value: valueToUse // store the "constructor argument" as "class member"
    };
    
    return prototype;
}

// And now let's add polymorphism:
function createSubClassInstance(valueToUse)
{
    var prototype = createInstance(valueToUse);
    prototype.create = function()
    {
        Console.print(this.value + ": SUBCLASS");
    };
    
    return prototype;
}

// Create two instances of the "class"
var x1 = createInstance(90);
var x2 = createInstance(120);

var x3 = createSubClassInstance(500);

// call the method of each instance
x1.create();
x2.create();
x3.create();

Ahhhhhh, yes I think I get that. I will give it a try! Thank you!

d.healey

@Christoph-Hart Nice, that's the kind of thing I was thinking of

d.healey

I just tried using the broadcaster wizard for the first time. I selected ComponentVisibility in the second screen, this is what it gave me

const var showAboutBroadcaster = Engine.createBroadcaster({
  "id": "showAboutBroadcaster",
  "args": ["component", "isVisible"],
  "tags": []
});

// attach to event Type
showAboutBroadcaster.attachToComponentProperties(["pnlAboutContainer"], "Temp");

// attach first listener
showAboutBroadcaster.addComponentPropertyListener(["pnlAboutContainer"], ["visible"], "temp", function(index, component, isVisible){
	return isVisible;
});

This gives an error argument amount mismatch: 2, Expected: 3

I changed it to attachToComponentVisibility and the issue is resolved.

Orvillain

@Christoph-Hart said in Broadcasters best practices:

You can do this kind of simple object oriented stuff by creating a JSON object and attaching functions as member, which will then access the JSON properties through the this.property syntax:

// This as close as you'll get to object oriented programming in HISE Script
function createInstance(valueToUse)
{
    var prototype = {
        create: function()
        {
            // Access properties of the "class" object with this
            Console.print(this.value);
        },
        value: valueToUse // store the "constructor argument" as "class member"
    };
    
    return prototype;
}

// And now let's add polymorphism:
function createSubClassInstance(valueToUse)
{
    var prototype = createInstance(valueToUse);
    prototype.create = function()
    {
        Console.print(this.value + ": SUBCLASS");
    };
    
    return prototype;
}

// Create two instances of the "class"
var x1 = createInstance(90);
var x2 = createInstance(120);

var x3 = createSubClassInstance(500);

// call the method of each instance
x1.create();
x2.create();
x3.create();

So just looking at this. I think I get it, and I can see how this would help me. For example here is what I have so far:

function Sampler(id)
{
	var sampler = {
		connectComponents: function()
		{
			this.pad = Content.getComponent("panel_" + this.id);
			this.sampler = Synth.getChildSynth("sampler_" + this.id);
			this.processor = Synth.getAudioSampleProcessor("sampler_" + this.id);
			this.sequencer = undefined;
			
			
		},
		
		populateLayers: function()
		{
			for (i = 0; i < layer_count; i++)
			{
				this.layers[i] = {
					'audiofile': this.processor.getAudioFile(i),
					'ui_parameters': {},
					'loop_panel': Content.getComponent("loopdragger_" + this.id),
					'waveform_panel': Content.getComponent("waveform_" + this.id),


				};
			}
		},
		
		connectCallbacks: function()
		{
			this.pad.setFileDropCallback("Drop Only", "*.wav", load_sample);
		},
		id: id,
		layers: {},
	};
	
	
	return sampler;
}

It'll get more interesting when I actually write a function to check if a component exists, and if it doesn't, create it.

d.healey

@d-healey said in Broadcasters best practices:

I just tried using the broadcaster wizard for the first time. I selected ComponentVisibility in the second screen, this is what it gave me
const var showAboutBroadcaster = Engine.createBroadcaster({
  "id": "showAboutBroadcaster",
  "args": ["component", "isVisible"],
  "tags": []
});

// attach to event Type
showAboutBroadcaster.attachToComponentProperties(["pnlAboutContainer"], "Temp");

// attach first listener
showAboutBroadcaster.addComponentPropertyListener(["pnlAboutContainer"], ["visible"], "temp", function(index, component, isVisible){
	return isVisible;
});
This gives an error argument amount mismatch: 2, Expected: 3

I changed it to attachToComponentVisibility and the issue is resolved.

Any ideas about this one Christoph? Is it a bug or did I use the wrong settings in the wizard?

aaronventure

@d-healey your function prototype is correct, now just make the arguments for the broadcaster match, i. e. add index to the args

d.healey

@aaronventure This is auto-generated by the broadcaster wizard - and it doesn't work, therefore I think it's a bug. It should be using attachToComponentVisibility, but it isn't.

aaronventure

@d-healey ah gotcha

d.healey

This is confusing

I had no idea what was wanted here, but it's a string (must have quotes)

I tried to add multiple events to the EQ broadcaster and the output was "BandAdded, BandRemoved, BandSelected" which doesn't work. It should be ["BandAdded", "BandRemoved", "BandSelected"]

Christoph Hart

@d-healey said in Broadcasters best practices:

I had no idea what was wanted here, but it's a string (must have quotes)

You can pass any object into the addCallback() function which will be assigned as this object in the executed function:

const var list = [1, 2, 3];

bc.addCallback(list, "something", function()
{
   for(n in this)
      Console.print(n); // 1, 2, 3
});

In this case you would just enter list into the This Object field.

The other issues you mentioned are fixed now.

d.healey

@Christoph-Hart Ah ok that makes sense, thanks

Lindon

@d-healey said in Broadcasters best practices:

@Christoph-Hart Ah ok that makes sense, thanks

does this mean you are investigating Broadcasters with a view to doing a video on it? (fingers crossed here...)

d.healey

@Lindon I've been using them since they were a thing. I'll make a broadcaster video for this weekend

Christoph Hart

@d-healey If you find any UX hurdles during the making of the video, let me know then I'll clean it up.

d.healey

Can broadcasters be defined as global? I might have finally found a use case for a global variable.

In my project I have a few MIDI processors that do things when the user changes articulation. My current method of handling this is each of the scripts has a knob to keep track of the current articulation. And when the articulation is changed all these knobs are updated and their callbacks triggered.

I'm thinking though it might be nice to just have a global articulation watcher instead of these knobs. That way the scripts will be more independent - which is the opposite of my usual argument against globals :)

d.healey

@d-healey said in Broadcasters best practices:

Can broadcasters be defined as global?

Well I thought this was working, but then a user noticed a bug. If in the DAW the track with the plugin is duplicated the broadcaster behaviour seems to break. Are globals shared between plugin instances somehow?

Broadcasters best practices

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