Change color of three.js mesh using gui.dat

Question

I have a three.js mesh loaded from an STL file:

    var loader = new THREE.STLLoader();         
    var materialmodel = new THREE.MeshPhongMaterial( 
        { 
            color: 0xFF0000, 
            specular: 0x222222, 
            shininess: 75 
        } 
        );

    function model()    
        {

            loader.load( 'models/stl/binary/model.stl', function ( geometry ) {
                var meshMaterial = materialmodel;
                var model = new THREE.Mesh( geometry, meshMaterial );
                model.scale.set( 0.02, 0.02, 0.02 );        
                model.castShadow = true;
                model.receiveShadow = true;
                model.geometry.center();                            
                scene.add(model);
                render();
            } );
        }
    model();

When I call the model function in my page, the model renders as expected.

I want to use dat.gui to as a lightweight interface for on the fly changes.

My first experiment is changing the color of the model.

The code I'm using is this:

            var params = {
                modelcolor: 0xff0000,  //RED
            };

            var gui = new dat.GUI();
            var folder = gui.addFolder( 'Model Colour' );
            folder.addColor( params, 'modelcolor' )
                .name('Model Color')
                .listen()
                .onChange( function() { materialmodel.MeshPhongMaterial.color.set( params.modelcolor); } );                  
            folder.open();

DAT.GUIs color picker appears fine, and I can select a color from the picker and the new hex value will display.

However, the model/mesh itself doesn't update with the newly selected colour.

I'm wondering if it's something to do with how I'm changing the color materialmodel.MeshPhongMaterial.color.set( params.modelcolor); (I've tried different ways of doing this with no luck).

I've seen a post here (one of the answers) where they're doing this using model.material.color.set(params.color) in their example. My owen material properties are defined in a variable using a THREE.MeshPhongMaterial.....

Assuming this is where I've gone wrong, how can I change the color dynamically of a nested prroperty buried in a variable like this?

Answer 1

I didn't get why did you use .listen(), possibly there's a certain reason.

In .onUpdate function you're using materialmodel, which is a material itself, and then you're setting .MeshPhongMaterial property that doesn't exist. Looks like you simply overlooked it.

Here is a working example:

var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 1, 1000);
camera.position.set(0, 0, 10);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

var light = new THREE.DirectionalLight(0xffffff, 0.5);
light.position.setScalar(10);
scene.add(light);
scene.add(new THREE.AmbientLight(0xffffff, 0.5));

var materialmodel = new THREE.MeshPhongMaterial({
  color: 0xFF0000,
  specular: 0x222222,
  shininess: 75
});
var geometrymodel = new THREE.SphereBufferGeometry(5, 32, 16);

var model = new THREE.Mesh(geometrymodel, materialmodel);
scene.add(model);

var params = {
  modelcolor: "#ff0000"
};

var gui = new dat.GUI();
var folder = gui.addFolder('Model Colour');
folder.addColor(params, 'modelcolor')
  .name('Model Color')
  .onChange(function() {
    materialmodel.color.set(params.modelcolor);
  });
folder.open();


render();

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

body {
  overflow: hidden;
  margin: 0;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/96/three.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/dat-gui/0.7.2/dat.gui.min.js"></script>