threejs/m6.html at master · ethancodes/threejs · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <meta charset=utf-8>
    <title>three.js</title>
    <style>
      body { margin: 0; }
      canvas { width: 100%; height: 100% }
    </style>
  </head>
  <body>
    <script src="../js/three.js"></script>
    <script src="../js/helpers.js"></script>
    <script>

      /*
        triangles
        what i want to do is draw three equilateral triangles
        that touch corners
        forming another equilateral triangle
        */

      var debugging = false;

      //
      // COLORS
      var colors = [
        '#E4B7E5',
        '#B288C0',
        '#7E5A9B',
        '#63458A',
        '#9A48D0'
      ];

      var scene = new THREE.Scene();
      //scene.background = new THREE.Color( 'white' );

      var camera = new THREE.PerspectiveCamera(
        75,
        window.innerWidth / window.innerHeight,
        1,
        500
      );
      camera.position.set( 0, 0, 300 );
      camera.lookAt( new THREE.Vector3() );

      var renderer = new THREE.WebGLRenderer();
      renderer.setSize( window.innerWidth, window.innerHeight );
      document.body.appendChild( renderer.domElement );


      // pick a random color
      var random_color = colors[Math.floor(Math.random() * colors.length)];
      if (debugging) { console.log(random_color); }

      if (debugging) {
        drawX(origin, scene, '#ff0000');
      }

      var side = getRandomInt(100, 300);
      var transparency = 0.25;

      var material = new THREE.LineBasicMaterial( {
        color: random_color,
        transparent: true,
        opacity: transparency
      } );

      var shape;
      var num_triads = getRandomInt(3, 12);
      var deg = 120 / num_triads;

      for (var i = 0; i < num_triads; i++) {

        random_color = colors[Math.floor(Math.random() * colors.length)];
        if (debugging) { console.log(random_color); }
        material = new THREE.LineBasicMaterial( {
          color: random_color,
          transparent: true,
          opacity: transparency
        } );

        shape = drawTriad(side, 0, material);
        shape.rotation.z = ((deg * Math.PI) / 180) * i;
        scene.add( shape );
      }

      renderer.render( scene, camera );

      /*
                A
               / \
              F---B
             / \ / \
            E---D---C
      */
      function drawTriad(side, depth, material) {

        var h = (Math.sqrt(3) / 2) * side;
        if (debugging) {
          console.log("H: " + h.toString());
        }

        var points = [];
        var p;

        // A C E
        p = new THREE.Vector3( 0, (h + (h/3)), 0 );
        points.push( p );
        p = new THREE.Vector3( side, 0 - ((h/3) * 2), 0 );
        points.push( p );
        p = new THREE.Vector3( 0 - side, 0 - ((h/3) * 2), 0 );
        points.push( p );
        p = new THREE.Vector3( 0, (h + (h/3)), 0 );
        points.push( p );

        // but then remove B D F
        var hole_points = [];
        hole_points.push( new THREE.Vector2( side / 2, (h/3) ) );
        hole_points.push( new THREE.Vector2( 0, 0 - ((h/3) * 2) ) );
        hole_points.push( new THREE.Vector2( 0 - (side / 2), (h/3) ) );
        var hole_path = new THREE.Path( hole_points );

        var triad = new THREE.Shape( points );
        triad.holes.push( hole_path );
        var geometry = new THREE.ShapeGeometry( triad );
        var mesh = new THREE.Mesh( geometry, material );
        return mesh;

      }


      function drawX(v3, scene, c) {

        var material = new THREE.LineBasicMaterial( { color: c } );
        var geometry = new THREE.Geometry();
        geometry.vertices.push( new THREE.Vector3( v3.x + 3, v3.y + 3, 0 ) );
        geometry.vertices.push( new THREE.Vector3( v3.x - 3, v3.y - 3, 0 ) );
        scene.add( new THREE.Line( geometry, material ) );
        geometry = new THREE.Geometry();
        geometry.vertices.push( new THREE.Vector3( v3.x - 3, v3.y + 3, 0 ) );
        geometry.vertices.push( new THREE.Vector3( v3.x + 3, v3.y - 3, 0 ) );
        scene.add( new THREE.Line( geometry, material ) );

      }


    </script>
  </body>
</html>