select-triangles-hittest.js

// **********************
// Extension for displaying temporary triangle face for the primitives of viewer face.
// **********************

function SelectFaceExtension(viewer, options) {
  Autodesk.Viewing.Extension.call(this, viewer, options);

  // viewer object
  var _viewer = viewer;

  //  THREE.js triangle for the facet
  var _currentTriangle = null;


  // when mouse move
  this.onMouseMove = function (event) {

    // get current screen point
    var screenPoint = {
      x: event.clientX,
      y: event.clientY
    };
    // hit test
    var hitTest = _viewer.impl.hitTest(screenPoint.x,screenPoint.y,true);
    // draw the temporary triangle face
    if(hitTest)
      drawMeshData(hitTest);
  }

  function drawMeshData(hitTest) {

    if( _currentTriangle != null)
    {
      // remove the last triangle face
      _viewer.impl.scene.remove(_currentTriangle);
      _currentTriangle = null;
    }

    var currentFragId = hitTest.fragId;

    // fragment proxy
    var fragProxy = _viewer.impl.getFragmentProxy(
      _viewer.model,
      currentFragId);

    // render proxy
    var renderProxy = _viewer.impl.getRenderProxy(
            _viewer.model,
            currentFragId);

    fragProxy.getAnimTransform();

    // transformation from fragment space to WCS
    var matrix = renderProxy.matrixWorld;

    // geometry data of the fragment
    var geometry = renderProxy.geometry;

    // information of the fragment
    var attributes = geometry.attributes;

    if (attributes.index !== undefined) {

      // index array of the vertices
      var indices = attributes.index.array || geometry.ib;
      // position array of the fragment
      var positions = geometry.vb ? geometry.vb : attributes.position.array;
      // unit range of the  vertices in the position array
      var stride = geometry.vb ? geometry.vbstride : 3;
      // geometry offset if any
      var offsets = geometry.offsets;

      // vertices
      var vA = new THREE.Vector3();
      var vB = new THREE.Vector3();
      var vC = new THREE.Vector3();

      // index of the vertices of the specific viewer face
      var a = hitTest.face.a;
      var b = hitTest.face.b;
      var c = hitTest.face.c;

      // positions of  the vertices
      vA.fromArray(positions, a* stride);
      vB.fromArray(positions, b* stride);
      vC.fromArray(positions, c* stride);

      // transform to WCS in model space
      vA.applyMatrix4(matrix);
      vB.applyMatrix4(matrix);
      vC.applyMatrix4(matrix);

      // normal of this facet
      normal =  hitTest.face.normal;

      // offset the temporary triangle above the native face
      var sal = 0.2;
      vA.x += normal.x * sal;vA.y += normal.y * sal;vA.z += normal.z*sal;
      vB.x += normal.x * sal;vB.y += normal.y * sal;vB.z += normal.z*sal;
      vC.x += normal.x * sal;vC.y += normal.y * sal;vC.z += normal.z*sal;

      // build THREE.js face
      var geomface = new THREE.Geometry();

      geomface.vertices.push(
        new THREE.Vector3( vA.x,  vA.y, vA.z ),
        new THREE.Vector3( vB.x,  vB.y, vB.z ),
        new THREE.Vector3(  vC.x,  vC.y, vC.z )
      );

      // face sequence
      var face = new THREE.Face3(0, 1, 2);

      // will use vertex color
      face.vertexColors[0] = new THREE.Color(0xff0000); // red
      face.vertexColors[1] = new THREE.Color(0x00ff00); // green
      face.vertexColors[2] = new THREE.Color(0x0000ff); // blue

      geomface.faces.push(face);
      geomface.computeBoundingSphere();
      geometry.computeFaceNormals();

      // vertex material
      var localmaterial = new THREE.MeshBasicMaterial({vertexColors: THREE.VertexColors});

      // create this triangle
      _currentTriangle = new THREE.Mesh(geomface, localmaterial);

      // add the triangle to the scene
      _viewer.impl.scene.add(_currentTriangle);
      _viewer.impl.invalidate(true, false, true);
    } 
  }

}
SelectFaceExtension.prototype = Object.create(Autodesk.Viewing.Extension.prototype);
SelectFaceExtension.prototype.constructor = SelectFaceExtension;

SelectFaceExtension.prototype.load = function() {

  console.log('SelectFaceExtension.prototype.load');

  $(_viewer.container).
  bind("mousemove", this.onMouseMove);

  return true;
};



SelectFaceExtension.prototype.unload = function() {

  console.log('SelectFaceExtension unload');

  // undeligate the event
  $(_viewer.container).
  unbind("mousemove", this.onMouseMove);

  console.log('mousemove unbinded');

  return true;
};

Autodesk.Viewing.theExtensionManager.registerExtension('SelectFaceExtension', SelectFaceExtension);