CODEWITHSUNDEEP
javascripthtmlthree.js
ZedBee
ZedBee

Reputation: 2378

THREE.js Ray Intersect fails by adding div

My Three.js script runs fine when there is only one target div on the page (which holds renderer.domElement). As soon as I add another div with fixed height and width above the target div, ray.intersectObjects returns null. I doubt that the vector that I am creating for ray is causing the problem. Here is the code.

var vector = new THREE.Vector3( ( event.clientX / divWidth ) * 2 - 1, -( event.clientY / divHeight ) * 2 + 1, 0.5 );

projector.unprojectVector( vector, camera );

var ray = new THREE.Ray( camera.position, vector.subSelf( camera.position ).normalize() );

var intersects = ray.intersectObjects( myObjects, true );

Any ideas on how I can solve this.

EDIT: it is now THREE.Raycaster (three.js r.56)

Upvotes: 21

Views: 16181

Answers (4)

WestLangley
WestLangley

Reputation: 104803

The short answer is you have to take into consideration the offset of the canvas.

The long answer depends on how your code is written, so I'll give you two answers, which should cover the bases.

Assume your HTML is something like this:

<style>
    #canvas {
        width: 200px;
        height: 200px;
        margin: 100px;
        padding: 0px;
        position: static; /* fixed or static */
        top: 100px;
        left: 100px;
    }
</style>

<body>
    <div id="canvas"></div>
</body>

Your JS is something like this:

const CANVAS_WIDTH = 200,
CANVAS_HEIGHT = 200;

const container = document.getElementById( 'canvas' );
document.body.appendChild( container );

const renderer = new THREE.WebGLRenderer();
renderer.setPixelRatio( window.devicePixelRatio );
renderer.setSize( CANVAS_WIDTH, CANVAS_HEIGHT );
container.appendChild( renderer.domElement );

Method 1 For the following method to work correctly, set the canvas position static; margin > 0 and padding > 0 are OK

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

Method 2 For this alternate method, set the canvas position fixed; set top > 0, set left > 0; padding must be 0; margin > 0 is OK

mouse.x = ( ( event.clientX - container.offsetLeft ) / container.clientWidth ) * 2 - 1;
mouse.y = - ( ( event.clientY - container.offsetTop ) / container.clientHeight ) * 2 + 1;

Here is a Fiddle if you want to experiment: https://jsfiddle.net/uf4c0ws9/

EDIT: Fiddle updated to three.js r.150

Upvotes: 48

Cezary Cezary
Cezary Cezary

Reputation: 41

I had a div (slider) with position absolute and a canvas nested inside.

<div class='slider'><div id="canvas-container"></div></div>

const canvasContainer: HTMLElement = document.getElementById('canvas-container');

this.renderer.setSize(canvasContainer.clientWidth, canvasContainer.clientHeight);
canvasContainer.appendChild(this.renderer.domElement);


const renderer = this.renderer.domElement.getBoundingClientRect();
this.mouse.x = ( ( e.clientX - renderer.left ) / ( renderer.right - renderer.left ) ) * 2 - 1;
this.mouse.y = - ( ( e.clientY - renderer.top ) / ( renderer.bottom - renderer.top) ) * 2 + 1;

this.raycaster.intersectObject(this.model, true);

Upvotes: 0

LF-DevJourney
LF-DevJourney

Reputation: 28529

enent.clientX is the client window offset, so to calculate the mouse position we also have to use the renderer element client window offset. Use the element.getBoundingClientRect() to get the element rect offset the window.

var rect = renderer.domElement.getBoundingClientRect();
mouse.x = ( ( event.clientX - rect.left ) / ( rect.width - rect.left ) ) * 2 - 1;
mouse.y = - ( ( event.clientY - rect.top ) / ( rect.bottom - rect.top) ) * 2 + 1;


<html>
<head>
<script src="http://threejs.org/build/three.min.js"></script>

    <link rel="stylesheet" href="http://libs.baidu.com/bootstrap/3.0.3/css/bootstrap.min.css" />


<style>
body {
    font-family: Monospace;
    background-color: #fff;
    margin: 0px;
    overflow: hidden;
}

#canvas {
    background-color: #000;
    width: 200px;
    height: 200px;
    border: 1px solid black;
    margin: 10px;
    padding: 0px;
    top: 10px;
    left: 100px;
}

.border {
    padding:10px; 
    margin:10px;
}

</style>
</head>
<body>
<div class="border">
	<div class="border">
		<div id="canvas"></div>
	</div>
</div>
<script>
// Three.js ray.intersects with offset canvas

var container, camera, scene, renderer, mesh,

    objects = [],
    
    count = 0,

    CANVAS_WIDTH = 200,
    CANVAS_HEIGHT = 200;

// info
info = document.createElement( 'div' );
info.style.position = 'absolute';
info.style.top = '30px';
info.style.width = '100%';
info.style.textAlign = 'center';
info.style.color = '#f00';
info.style.backgroundColor = 'transparent';
info.style.zIndex = '1';
info.style.fontFamily = 'Monospace';
info.innerHTML = 'INTERSECT Count: ' + count;
info.style.userSelect = "none";
info.style.webkitUserSelect = "none";
info.style.MozUserSelect = "none";
document.body.appendChild( info );

container = document.getElementById( 'canvas' );

renderer = new THREE.WebGLRenderer();
renderer.setSize( CANVAS_WIDTH, CANVAS_HEIGHT );
container.appendChild( renderer.domElement );

scene = new THREE.Scene();

camera = new THREE.PerspectiveCamera( 45, CANVAS_WIDTH / CANVAS_HEIGHT, 1, 1000 );
camera.position.y = 250;
camera.position.z = 500;
camera.lookAt( scene.position );
scene.add( camera );

scene.add( new THREE.AmbientLight( 0x222222 ) );

var light = new THREE.PointLight( 0xffffff, 1 );
camera.add( light );

mesh = new THREE.Mesh( 
	new THREE.BoxGeometry( 200, 200, 200, 1, 1, 1 ), 
	new THREE.MeshPhongMaterial( { color : 0x0080ff } 
) );
scene.add( mesh );
objects.push( mesh );

// find intersections
var raycaster = new THREE.Raycaster();
var mouse = new THREE.Vector2();

// mouse listener
document.addEventListener( 'mousedown', function( event ) {
    
 var rect = renderer.domElement.getBoundingClientRect();
mouse.x = ( ( event.clientX - rect.left ) / ( rect.width - rect.left ) ) * 2 - 1;
mouse.y = - ( ( event.clientY - rect.top ) / ( rect.bottom - rect.top) ) * 2 + 1;
  
	raycaster.setFromCamera( mouse, camera );

    intersects = raycaster.intersectObjects( objects );

    if ( intersects.length > 0 ) {
        
        info.innerHTML = 'INTERSECT Count: ' + ++count;
        
    }

}, false );

function render() {

    mesh.rotation.y += 0.01;
    
    renderer.render( scene, camera );

}

(function animate() {

    requestAnimationFrame( animate );

    render();

})();

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

Upvotes: 17

danivicario
danivicario

Reputation: 1801

WestLangley, thanks a lot for your explanation. It was really helpful as usual.

In my case, I had my chart in a div absolutely positioned, so I had to do this:

    var offset = $('.rightBlock').offset();


    mouse.x = ( ( event.clientX - offset.left ) / renderer.domElement.width ) * 2 - 1;
    mouse.y = - ( ( event.clientY - offset.top ) / renderer.domElement.height ) * 2 + 1;

Where rightBlock is my container, that uses only 70% of the screen.

You inspired me and help me solving this problematic issue! Thanks a lot.

Upvotes: 4

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