createCanvas(400, 400, WEBGL);

}

​

function draw() {

  background(200,200,0);

  strokeWeight(2);

  rotateZ(frameCount * 0.01);

  rotateX(frameCount * 0.01);

  rotateY(frameCount * 0.01);

  //drawingContext.setLineDash([5, 10]);

  stroke(200,0,0);

  line(0,5,0,100,105,100); //__ use some offset to see both

  stroke(0,0,200);

  dash_line(0, 0, 0, 100, 100, 100, 2, 5);

}

​

function dash_line(x1, y1, z1, x2, y2, z2, lon, loff) {

  let v1 = createVector(x1, y1, z1);

  let v2 = createVector(x2, y2, z2);

  let vd = p5.Vector.sub(v2, v1);

  let llong = vd.mag();

  let kn  = int( llong/(lon + loff) );

  push();

  translate(x1, y1, z1);

  let vdon  = vd.copy().setMag(lon); //_____ make line

  let vdt = vd.copy().setMag(lon+loff);  //_ translate to next line

  for (let k = 0; k < kn; k++) {

    line(0, 0, 0, vdon.x, vdon.y, vdon.z);

    translate(vdt.x, vdt.y, vdt.z);

  }

  pop();

}