const curveRes = 50;

let c, f;

let clicked = null;

let moving = null;

const mindist = 8;

let {Vector} = p5;

let back;

​

function preload()

{

 back = loadImage('road-1.png'); 

}

​

function setup() {

  createCanvas(900, 900).parent('content');

  doHTML();

  f = new follower();

}

​

function draw() {

  background(back);

  c.show();

  if (show.checked()) {

    fill(0);

    road(c, 5).show(c.evenlySpaced(1), c.isclosed);

  }

  f.follow(c, 10);

}

​

​

//function to generate quadratic bezier curve

function quadcurve(a, b, c, t) {

  let p0 = p5.Vector.lerp(a, b, t);

  let p1 = p5.Vector.lerp(b, c, t);

  return p5.Vector.lerp(p0, p1, t);

}

​

//function to generate cubic bezier curve from two quadratic curves

function cubicCurve(a, b, c, d, t) {

  let p0 = quadcurve(a, b, c, t);

  let p1 = quadcurve(b, c, d, t);

  return p5.Vector.lerp(p0, p1, t);

}

​

function mousePressed() {

  mouse = createVector(mouseX, mouseY);

  // this is for adding points

  if (keyIsDown(SHIFT)) {

    // get the closest point on the curve to the mouse

    let close = null;

    for (let i = 0; i < c.path.length; i++) {

      let seg = c.path[i];

      for (let j = 0; j < seg.length; j++) {

        let p = seg[j];

        if (p.dist(mouse) < mindist) {

          close = [p, i];

        }

      }

    }

    // if there is a closest then add a point on the seg

    if (close != null) {

      c.Split(close[0], close[1]);

    // if not add a regular point

    } else {

      c.addSeg(createVector(mouseX, mouseY));

    }

  }

  // this is for removing points

  else if (mouseButton === RIGHT || keyIsDown(82)) {

    for (let i = 0; i < c.length; i++) {

      let node = c[i];

      if (node.dist(createVector(mouseX, mouseY)) < r) {

        c.remove(i);

      }

    }

  }

}

​

function mouseDragged() {

  let mouse = createVector(mouseX, mouseY);

  if(c.centerdist < r)

  {

   moving = null; 

  }

  if((mouse.dist(c.center) < r*2 || moving != null) && c.centerdist > r && clicked == null)

    {

      moving = true;

      let dif = Vector.sub(c.center, mouse);

      for(let i = 0; i < c.length; i++)

      {

       c[i].sub(dif); 

      }

    }

  else if (clicked == null) {

    for (let i = 0; i < c.length; i++) {

      let node = c[i];

      if (node.dist(mouse) < r) {

        clicked = i;

      }

    }

  }

  if (clicked != null) {

    c.movePoint(clicked, mouse);

  }

}

​

function mouseReleased() {

  clicked = null;

  moving = null;

}

​

function road(path, spacing, w = 50)

{

  // let w = 100;

 let points = path.evenlySpaced(spacing);

  let verts = new Array(points.length*2);

  let numTris = 2*(points.length-1) + ((path.isclosed)?2:0);

  let tris = new Array(numTris*3);

  let vertindex = 0;

  let triIndex = 0;

  for(let i = 0; i < points.length; i++)

  {

    let forward = createVector();

    if(i < points.length-1 || path.isclosed)

    {

     forward.add(points[(i+1)%points.length].copy().sub(points[i].copy()));

    }

    else if(i > 0 || path.isclosed)

    {

      forward.add(points[i].copy().sub(points[(i-1+points.length)%points.length].copy()));

    }

    forward.normalize();

    let left = createVector(-forward.y, forward.x);

    verts[vertindex] = points[i].copy().add(left.copy().mult(w/2));

    verts[vertindex+1] = points[i].copy().sub(left.copy().mult(w/2));

    if(i < points.length-1 || path.isclosed)

    {

       tris[triIndex] = vertindex; 

       tris[triIndex+1] = (vertindex+2)%verts.length; 

       tris[triIndex+2] = vertindex+1; 

       tris[triIndex+3] = vertindex+1; 

       tris[triIndex+4] = (vertindex+2)%verts.length; 

       tris[triIndex+5] = (vertindex+3)%verts.length; 

    }

    vertindex += 2;

    triIndex+=6;

  }

  return new mesh(verts, tris, points);

}