Change the color of an object (.dae or gltf) in “AR.JS”

Question

I\'m trying to change the color of an object I created in blender. I can change the color of objects like \"a-box, a-sphere\" in the html code itself, but with objects inside tr

Answer 1

Enitities that contain GLTF models are complex, as they contain many models inside the gltf container. You can't use setAttribute on the models inside a gltf like you can with other primitives. Instead you have to treat them like THREEjs models. That means you need to make a custom component that will 'traverse' through the gltf, and find the models, and store variable references to them, and then later you can change the parameters of these models on the THREEjs level. For example

AFRAME.registerComponent('treeman', {
        init: function(){
            let el = this.el;
            let self = this;
            self.trees = [];              
            el.addEventListener("model-loaded", e =>{
                let tree3D = el.getObject3D('mesh'); // get the THREEjs group
                if (!tree3D){return;}    
              console.log('tree3D', tree3D); // log the THREEjs group so you can look 
                                          at all of its contents and parameters.
                tree3D.traverse(function(node){ // this is how you loop through 
                                                  (traverse) the models
                    if (node.isMesh){   
                      console.log(node);
                        self.trees.push(node);
                      if(node.name == "Trunk_A"){
                        self.treeMat = node.material; // store a reference to the 
                                         material you want to modify later
                      }
                      node.material.map = null; // removes the texture so we can see 
                               color clearly
                    }
                });
          });

Then later, you can access this component with event listener functions, and do stuff to materials. like this

 el.addEventListener('changecolor', e =>{               
            let colorp = e.detail.color;
            let colorHex = Number(colorp.replace('#', '0x'));
            let color3D = new THREE.Color(colorHex);
            self.treeMat.color = color3D;                
          });

Note that we have to put the color into data structures that THREEjs wants, like the color object. All of this is a lot of work compared to the simplicity of Aframe, but you have much more control and you can see precisely what is happening under the hood.

glitch here.