Change color of mesh using mouseover in three js

Martin Leman picture Martin Leman · Jul 11, 2016 · Viewed 15.9k times · Source

I've put together a WebGL script that displays several meshes using jsonloader and three.js and I now want to add MouseOver and onClick events. The first of these is simply changing the colour of the mesh when the mouse hovers over it:

function render() {
  requestAnimationFrame(render);    
  mesh.rotation.z += 0.090;    
  raycaster.setFromCamera(mouse, camera);    
  var intersects = raycaster.intersectObjects(scene.children);  

  for (var i = 0; i < intersects.length; i++) {    
    intersects[i].object.material.color.set(0xff0000);    
  }    
  renderer.render(scene, camera);

}

The render function above allows me to change the colour of any mesh to red by hovering over it. I've tried several if/else variants to try and have this effect only work when the mouse is over a mesh but I can't get it to work- it just stays red. Can anyone suggest how I might amend my script?

Thanks.

Answer

Wilt picture Wilt · Jul 12, 2016

You have to set the color back to the original color on mouse out, that won't happen automatically...

Check this example on http://stemkoski.github.io specifically the update method:

Here a fiddle with a demo updated to the latest three.js master:

// 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( scene.children );

// INTERSECTED = the object in the scene currently closest to the camera 
//      and intersected by the Ray projected from the mouse position    

// if there is one (or more) intersections
if ( intersects.length > 0 )
{
    // if the closest object intersected is not the currently stored intersection object
    if ( intersects[ 0 ].object != INTERSECTED )
    {
        // restore previous intersection object (if it exists) to its original color
        if ( INTERSECTED )
            INTERSECTED.material.color.setHex( INTERSECTED.currentHex );
        // store reference to closest object as current intersection object
        INTERSECTED = intersects[ 0 ].object;
        // store color of closest object (for later restoration)
        INTERSECTED.currentHex = INTERSECTED.material.color.getHex();
        // set a new color for closest object
        INTERSECTED.material.color.setHex( 0xffff00 );
    }
}
else // there are no intersections
{
    // restore previous intersection object (if it exists) to its original color
    if ( INTERSECTED )
        INTERSECTED.material.color.setHex( INTERSECTED.currentHex );
    // remove previous intersection object reference
    //     by setting current intersection object to "nothing"
    INTERSECTED = null;
}