Having a ControlP5 controller inside a class?

velvetkev..

Having a ControlP5 controller inside a class?

in Contributed Library Questions • 10 months ago

Hello,

Is it possible to have a controlP5 controller as a property of an object? I'd like to be able to create a number of objects and control their parameters without having to manually create each slider for each object as that gets unwieldy quickly!

Here's an example of what I mean:

class MyClass{
float theValue;
float xpos, ypos;
MyClass(float XPOS, float YPOS){
cp5.addSlider("theValue").setRange(0, 255).setValue(127).linebreak();
xpos= XPOS;
ypos=YPOS;
}
void display(){
fill(theValue);
rect(xpos, ypos, 150, 150);
}
}

When you create two of those objects, you get a cp5 error message: "WARNING: Controller with name "/theValue" already exists. overwriting reference of existing controller."

I'm also not quite sure whether the class should have it's own controlEvent method- I assume so, as I can't see any other way to do it without duplicating the code for each object (which is what I'm trying to avoid).

Any pointers appreciated.

Replies(6)

timpulver

Re: Having a ControlP5 controller inside a class?

10 months ago

Yes, that's possible!

sketch.pde

import controlP5.*;
MyClass[] myClasses;
void setup() {
size(500, 500);
MyClass.setPApplet(this);
myClasses = new MyClass[2];
myClasses[0] = new MyClass(40, 40);
myClasses[1] = new MyClass(40, 60);
}
void draw(){}

MyClass.java

import processing.core.PApplet;
import controlP5.*;
public class MyClass implements ControlListener {
float theValue;
float xpos, ypos;
static ControlP5 cp5;
static PApplet p;
static int controllerNumber = 0;
int value = 0;
String name;
MyClass(float xpos, float ypos) {
if (cp5 == null) {
cp5 = new ControlP5(p);
}
this.xpos = xpos;
this.ypos = ypos;
name = "controller" + String.valueOf(controllerNumber);
cp5.addSlider(name).setRange(0, 255).setValue(127).linebreak();
cp5.addListener(this);
controllerNumber++;
p.registerMethod("pre", this);
}
public void controlEvent(ControlEvent theEvent) {
if (theEvent.getName().equals(name)) {
theValue = theEvent.getValue();
p.println("got value");
}
}
public void pre(){
p.fill(theValue);
p.rect(xpos, ypos, 10, 10);
}
static void setPApplet(PApplet p_) {
p = p_;
}
}

If you are not running Processing 2.0 you have to replace

p.registerMethod("pre", this)

with

p.registerPre(this);

velvetkev..

Re: Having a ControlP5 controller inside a class?

10 months ago

Heh, that was somewhat more complicated than I expected

Thanks a lot, trying to work that in to my project now.

andreas.s..

Re: Having a ControlP5 controller inside a class?

10 months ago

Using the ControlListener is one way to channel a value change to a custom class. The ControlListener has the advantage that you have full control over a ControlEvent but requires a bit more implementation as shown by timpulver. An alternative is to using the plugTo() method (see example) of a controller which allows you to link a value change directly to a variable, in your case add plugTo(this) before setValue() when adding a slider inside MyClass:

// tested with processing 2.0b3, controlP5 2.0.3
cp5.addSlider("theValue")
.setRange(0, 255)
.plugTo(this)
.setValue(127)
;
// the slider 'theValue' will automatically attach itself to the variable theValue inside MyClass

Also note that when you add more than 1 instance of MyClass to your program controlP5 will override existing controllers with the same index. In your case a slider for each instance of MyClass uses 'theValue' as index and my suggestions is to add a suffix or prefix that varies for each instance, so the implementation from above should change to:

class MyClass {
float theValue;
MyClass(String thePrefix, float xpos, float ypos) {
cp5.addSlider("theValue-"+thePrefix)
.setRange(0, 255)
.plugTo(this, "theValue")
.setValue(127)
.setLabel("value")
;
// the slider will automatically attach itself to the variable theValue inside MyClass
// ... etc.
}
// etc..
}

Brian K

Re: Having a ControlP5 controller inside a class?

1 month ago

I thought I would resurrect this thread as it seems that the code-example doesn't work anymore. As soon as I try to create a slider inside a class I get a NullPointerException. Got any idea why this has changed?

andreas.s..

Re: Having a ControlP5 controller inside a class?

1 month ago

Hi, I have to check why this is not behaving properly (for fields), thanks for posting. Meanwhile, the following works for me.

import controlP5.*;
ControlP5 cp5;
Test t;
void setup() {
cp5 = new ControlP5( this );
t = new Test( "test" );
}
void draw() {
println( t.value );
}
class Test {
int value;
Test( String thePrefix ) {
cp5.addSlider( "value-"+thePrefix )
.setRange( 0, 255 )
.plugTo( this, "setValue" )
.setValue( 127 )
.setLabel("value")
;
}
void setValue(int theValue) {
value = theValue;
}
}

andreas schlegel, http://www.sojamo.de

Brian K

Re: Having a ControlP5 controller inside a class?

1 month ago

As usual the solution was very simple. I simply needed to initialize the library before declaring the objects in setup.

void setup() {
test = new MyClass();
cp5 = new ControlP5(this); }

Won't work...

void setup() {
cp5 = new ControlP5(this);
test = new MyClass(); }

Will work.

And thanks for the library. It makes the project I'm working on alot easier.

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