Orthographic camera and selecting objects with raycast
Asked Answered
M

2

12

I am running into a bit of difficulty selecting objects with the orthographic camera using the raycaster. Though, I have no problem with it when I use a perspective camera. The only thing I am changing when switching between the two is the type camera.

I am able to select faces on the orthographic view, but it is only loosely related to where I am clicking on the screen. When I can click far away from the object and it will still come back as if it has hit the object near its center.

Any ideas on what I am missing here?

I am basing much of my code on this example, and am hoping to achieve a very similar result from my code. (this example I'm referencing uses the perspective camera)

Any help is much appreciated

<html>
<head>
  <style>
    canvas {
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
      position: fixed;
      background-color: #111115;
    }
  </style>
</head>
<body id='c'>
  <script src="js/three.js"></script>

  <script>

    var obj = [];
    var mouse ={};
    var zoom = 2;

    var scene = new THREE.Scene();

    //switch between these two and see the difference:
    //var camera =  new THREE.OrthographicCamera(window.innerWidth / -zoom, window.innerWidth / zoom, window.innerHeight / zoom, window.innerHeight / -zoom, -1000, 1000);
    var camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 1000 );

    camera.position = new THREE.Vector3(100,100,100);
    camera.lookAt(new THREE.Vector3(0,0,0));

    // this material causes a mesh to use colors assigned to faces
    var material = new THREE.MeshBasicMaterial( 
    { color: 0xffffff, vertexColors: THREE.FaceColors } );

    var sphereGeometry = new THREE.SphereGeometry( 80, 32, 16 );
    for ( var i = 0; i < sphereGeometry.faces.length; i++ ) 
    {
      face = sphereGeometry.faces[ i ]; 
      face.color.setRGB( 0, 0, 0.8 * Math.random() + 0.2 );     
    }
    obj['box'] = {};
    obj['box'] = new THREE.Mesh( sphereGeometry, material );
    obj['box'].castShadow = true;
    obj['box'].receiveShadow = true;
    scene.add(obj['box']);

    var ambientLight = new THREE.AmbientLight(0xbbbbbb);
    scene.add(ambientLight);

    var directionalLight = new THREE.DirectionalLight(0xffffff, 1);
    directionalLight.position.set(-100, 40, 100);
    directionalLight.castShadow = true;
    directionalLight.shadowOnly = true;
    directionalLight.shadowDarkness = .5;
    scene.add(directionalLight); 

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

    projector = new THREE.Projector();
    document.addEventListener( 'mousedown', onDocumentMouseDown, false );
    function onDocumentMouseDown( event ) {
      // the following line would stop any other event handler from firing
      // (such as the mouse's TrackballControls)
      // event.preventDefault();

      console.log("Click.");

      // update the mouse variable
      mouse.x = ( event.clientX / window.innerWidth ) * 2 - 1;
      mouse.y = - ( event.clientY / window.innerHeight ) * 2 + 1;

      // find intersections

      // create a Ray with origin at the mouse position
      //   and direction into the scene (camera direction)
      var vector = new THREE.Vector3( mouse.x, mouse.y, 1 );
      projector.unprojectVector( vector, camera );
      var ray = new THREE.Raycaster( camera.position, vector.sub( camera.position ).normalize() );

      // create an array containing all objects in the scene with which the ray intersects
      var intersects = ray.intersectObjects( [obj['box']] );

      // if there is one (or more) intersections
      if ( intersects.length > 0 )
      {
        console.log("Hit @ " + toString( intersects[0].point ) );
        console.log(intersects);
        // change the color of the closest face.
        intersects[ 0 ].face.color.setRGB( 0.8 * Math.random() + 0.2, 0, 0 ); 
        intersects[ 0 ].object.geometry.colorsNeedUpdate = true;
      }
    }

    function toString(v) { return "[ " + v.x + ", " + v.y + ", " + v.z + " ]"; }

    var render = function() {
      requestAnimationFrame(render);
      renderer.render(scene, camera);
    };

    console.log(camera);
    console.log(obj['box'])
    render();

    </script>
</body>

I am hoping it is something simple that I just don't know about yet.

three.js r60

Matte answered 31/8, 2013 at 22:1 Comment(1)
Tip: Your OrthographicCamera near plane is negative. That's behind the camera. It should be positive. Also, the first four args are in world coordinates, not pixel coordinates, so do not get confused.Cent
C
21

Here is the pattern to use when raycasting with either an orthographic camera or perspective camera:

var raycaster = new THREE.Raycaster(); // create once
var mouse = new THREE.Vector2(); // create once

...

mouse.x = ( event.clientX / renderer.domElement.clientWidth ) * 2 - 1;
mouse.y = - ( event.clientY / renderer.domElement.clientHeight ) * 2 + 1;

raycaster.setFromCamera( mouse, camera );

var intersects = raycaster.intersectObjects( objects, recursiveFlag );

three.js r.84

Cent answered 31/8, 2013 at 23:25 Comment(3)
thx. uncomfortable, that picking code depends on the camera type.Deforest
...but much better than making itself within WebGL :)Consolation
Please add camera configuration because the snippet you presented is dependent on it.Cypress
T
2

One more note that might save you some trouble. If you have a camera like this:

var camera = new THREE.OrthographicCamera(0, window.innerWidth, -window.innerHeight, 0, -100, 100);

Then during raycasting, be sure to move the ray origin.z to camera.far for it to hit anything in the entire visible range:

this.ray.origin.set(0, 0, 0);
this.camera.localToWorld(this.ray.origin);
this.ray.setFromCamera(this.mouseCoord, this.camera);
this.ray.origin.z = this.camera.far;
Tristatristam answered 15/2, 2017 at 16:24 Comment(2)
Great :) I also add that this.ray = this.raycaster.rayGoodsized
Can you please show a full example?Eveliaevelin

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