Dynamic ropes 2

/*

Dynamic ropes 2

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The ropes are defined by a series of points which are simulated using verlet integration.

​

Controls:

  - Move the mouse over the ropes to interact with them.

  - Use the on-screen controls to effect the sim.

​

Author:

  Jason Labbe

​

Site:

  jasonlabbe3d.com

*/

​

var timesteps = 20;

var rigidBodies = [];

var img;

​

function preload() {

  img = loadImage('sky.jpg');

}

function setup() {

  createCanvas(windowWidth, windowHeight);

  thicknessSlider = new Slider("Line thickness", 0.1, 2, 0.5, 0.1, 100, 100);

  resolutionSlider = new Slider("Resolution", 0, 1, 0.75, 0.05, 100, thicknessSlider.pos().y+60);

  repulsionSizeSlider = new Slider("Repulsion size", 10, 150, 100, 25, 100, resolutionSlider.pos().y+60);

  gravitySlider = new Slider("Gravity", 0.01, 0.5, 0.2, 0.01, 100, repulsionSizeSlider.pos().y+60);

  airDragSlider = new Slider("Air drag", 0.95, 1, 0.995, 0.005, 100, gravitySlider.pos().y+60);

  massSlider = new Slider("Mass", 0.5, 3, 2, 0.5, 100, airDragSlider.pos().y+60);

  resetScene();

}

​

​

function resetScene() {

  rigidBodies = [];

  let xCount = 60;

  let yCount = 30;

  for (i = 0; i < xCount; i++) {

    let rb = new RigidBody();

​

    for (j = 0; j < yCount; j++) {

      // Get position and add a new point.

      let x = map(i, 0, xCount, width/2 - 300, width/2 + 300);

      let y = map(j, 0, yCount, 50, 600);

      let newPoint = rb.addPoint(x, y);

​

      // Snap the first point, otherwise connect points with segments.

      if (rb.points.length == 1) {

        newPoint.snap = true;

      } else {

        rb.addSegment(rb.points[rb.points.length-2], newPoint);

      }

    }

​

    rigidBodies.push(rb);

  }

}

​

​

function draw() {

  background(200);

  image(img,300,0);

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

    // Sim a line.

    rigidBodies[i].sim();

    // Draw a line.

    if (i < rigidBodies.length-1) {

      noFill();

      stroke(0);

      strokeWeight(thicknessSlider.value());

      // Draw many 'fake' lines that follow between the current and next lines, which are part of the sim.

      // This will increase its volume to look fuller without extra calculations.

      let resolution = map(resolutionSlider.value(), 0, 1, 1, 0.05);

      for (let weight = 0.0; weight < 1.0; weight+=resolution) {

        beginShape();

        for (let j = 0; j < rigidBodies[i].points.length; j++) {

          let x = lerp(rigidBodies[i].points[j].pos.x, rigidBodies[i+1].points[j].pos.x, weight);

          let y = lerp(rigidBodies[i].points[j].pos.y, rigidBodies[i+1].points[j].pos.y, weight);

          vertex(x, y);

        }

        endShape();       

      }

    }

  }

  // Draw mouse area.

  stroke(0, 50);

  strokeWeight(repulsionSizeSlider.value()*2);

  point(mouseX, mouseY);

  // Display sliders.

  thicknessSlider.display();

  resolutionSlider.display();

  repulsionSizeSlider.display();

  gravitySlider.display();

  airDragSlider.display();

  massSlider.display();

}

​

​

function keyPressed() {

  resetScene();

}