Instantiating object in p5.js instance mode

Question

I'm trying to instantiate an object on p5.js instance mode, however I've got lots of errors on the object's properties and functions.

var sketch1 = function(p){

    var dados = [];

    p.setup = function(){
        var canvas = p.createCanvas(640, 480);
        canvas.parent('area-sketch');

        p.button = p.createButton('Rolar dado');
        p.button.position(p.width, p.height);
        p.button.parent('area-sketch');
        p.button.mouseClicked(p.rolaDado);
    };

    p.draw = function(){
        if(dados.length>0){
            for(var i=0;i<dados.length;i++){
                dados[i].show();
            }
        }
    };

    p.rolaDado = function(){
        var total=0;
        if(dados.length>0){
            for(var i=0;i<dados.length;i++){
                dados[i].shuffle();
                total+=dados[i].getValor();
            }

            return(total);
        }
    };

    p.limpaDados = function(){
        dados = [];
    };

    p.criaDados = function(num){
        for(var i=0;i<num;i++){
            dados.push(new Dado());
        }
    };

    p.limpaTela = function(){
        p.clear();    
    };
};

var mesa_dados = new p5(sketch1);

function Dado(){   

    this.lado = 80;
    this.x = random(1,width-this.lado);
    this.y = random(1,height-this.lado);

    this.type = 6;

    this.show = function(){
        stroke(0,0,0);
        p.fill(255,255,255);

        p.rect(this.x,this.y, this.lado, this.lado);

        switch(this.type){
            case 1:
                fill(0,0,0);
                ellipse(this.x+this.lado*0.5, this.y+this.lado*0.5, 10, 10);
                break;
            case 2:
                fill(0,0,0);
                ellipse(this.x+this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                break;
            case 3:
                fill(0,0,0);
                ellipse(this.x+this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                ellipse(this.x+this.lado*0.5, this.y+this.lado*0.5, 10, 10);
                break;
            case 4:
                fill(0,0,0);
                ellipse(this.x+this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse(this.x+this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                break;
            case 5:
                fill(0,0,0);
                ellipse(this.x+this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse(this.x+this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                ellipse(this.x+this.lado*0.5, this.y+this.lado*0.5, 10, 10);
                break;
            case 6:
                fill(0,0,0);
                ellipse(this.x+this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, this.y+this.lado*0.25, 10, 10);
                ellipse(this.x+this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, (this.y+this.lado)-this.lado*0.25, 10, 10);
                ellipse(this.x+this.lado*0.25, this.y+this.lado*0.5, 10, 10);
                ellipse((this.x+this.lado)-this.lado*0.25, this.y+this.lado*0.5, 10, 10);
                break;
        }

    }

    this.clear = function(){

    }

    this.shuffle = function(){
        this.type = ceil(random(0,6));
    }

    this.shufflePos = function(){
        times = 100;
        speed = 50;
        this.xdirection = random(-1,1);
        this.ydirection = random(-1,1);
    }

    this.getValor = function(){
        return(this.type);
    }
}

When I try to run these code I've got the error:

Uncaught ReferenceError: random is not defined at new Dado (dado.js:4) at p5.p.criaDados (sketch.js:41)

I have this error for every function inside the object Dado. When I tested the code but in p5.js global mode I didn't get these errors.

coagmano · Accepted Answer · 2019-03-12 04:10:19Z

1

The function random as well as the calls to stroke, fill, and ellipse are all trying to use global versions of functions that p5 gives you.

To use these in instance mode, move your Dado definition into the sketch function and use the p instance passed into the function:

var sketch1 = function(p){

    // existing sketch code...

    function Dado(){   

    this.lado = 80;
    this.x = p.random(1,width-this.lado);
    this.y = p.random(1,height-this.lado);

    this.type = 6;

    this.show = function(){
        p.stroke(0,0,0);
        p.fill(255,255,255);

        p.rect(this.x,this.y, this.lado, this.lado);

        switch(this.type){
            case 1:
                p.fill(0,0,0);
                p.ellipse(this.x+this.lado*0.5, this.y+this.lado*0.5, 10, 10);
                break;
            case 2:
        // Rest of Dado etc...
}; // end of sketch1

answered Mar 12, 2019 at 4:10

coagmano

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2 Comments

Leonardo Over a year ago

It worked!! So in p5.js instance mode, because of the namespace, can't I have a class in an external file? Because I think that, in an external file, I could reuse that class in another piece of code.

coagmano Over a year ago

You can, but you will need to use dependency injection. Pass the p5 instance in the constructor so you can use it elsewhere in the class

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