NatureOfCode

P5.js

---

Project maintained by OlgaTorok Hosted on GitHub Pages — Theme by mattgraham

Vectors

Vector Motion - Constant Acceleration

Mover

The Mover class is created. The Mover’s location is set at half the width and half the height using the createVector() function. The velocity is set to 0 on this exercise so we can test the acceleration and the acceleration is set using the createVector() function and we give it a small number. The acceleration affects the velocity and the velocity in its turn affects the location of the object. Next we added the functions that create the objects.

The update function updates the object’s location and velocity by adding the acceleration to velocity and set the limit of the maximum velocity to 10. We then add the velocity to the location each frame. The display function creates the ellipse at the x and y locations with a stroke and fill. The checkEdge function checks if the ellipse leaves the canvas and it turns it around.

var Mover = function(){
    this.location = createVector(width / 2, height / 2);
    this.velocity = createVector(0, 0);
    this.acceleration = createVector(0.03, 0.04);

    this.update = function(){
        this.velocity.add(this.acceleration);
        this.velocity.limit(10);
        this.location.add(this.velocity);
    }

    this.display = function(){
        stroke(0);
        strokeWeight(2);
        fill(255);
        ellipse(this.location.x, this.location.y, 40, 40);
    }

    this.checkEdge = function(){
        if(this.location.x > width || this.location.x < 0){
            this.velocity.x = this.velocity.x * -1;
        }

        if(this.location.y > height || this.location.y < 0){
            this.velocity.y = this.velocity.y * -1;
        }
    }
}

Sketch

The global variable mover is added to be used in creating the objects. In the setup() function we create the canvas and we set the new Mover. The draw() function has the background and the functions are called from the Mover class so the movers are created.

var mover;

function setup(){
    createCanvas(650, 350);
    mover = new Mover();
}

function draw(){
    background(0);

    mover.update();
    mover.display();
    mover.checkEdge();
}

Result: