Three.js 项目导致手机崩溃

Question

I've been working on a three.js project to try and learn the framework. Got a basic model floating around that works fine on the desktop browser but will crash repeatedly on mobile. I uploaded the project on my server http://threedeesneaker.404vanity.com/

Is there any way to optimize this for mobile devices? I tried both chrome and safari for iPhone and iPad.

The code it self:

(function() {

var scene, camera, renderer;
var geometry, material, mesh, sneaker;

init();
animate();

function init() {

    scene = new THREE.Scene();
    var WIDTH = window.innerWidth,
        HEIGHT = window.innerHeight;

        var ambient = new THREE.AmbientLight( 0x444444 );
                scene.add( ambient );

    camera = new THREE.PerspectiveCamera( 3, WIDTH / HEIGHT, 1, 20000 );
    camera.position.z = 1000;



    window.addEventListener('resize', function() {
      var WIDTH = window.innerWidth,
          HEIGHT = window.innerHeight;
      renderer.setSize(WIDTH, HEIGHT);
      camera.aspect = WIDTH / HEIGHT;
      camera.updateProjectionMatrix();
    });

    geometry = new THREE.BoxGeometry( 200, 200, 200 );
    material = new THREE.MeshBasicMaterial( { color: 0xff0000, wireframe: true } );

    mesh = new THREE.Mesh( geometry, material );
    scene.add( mesh );


    // prepare loader and load the model
    var oLoader = new THREE.OBJMTLLoader();
    oLoader.load('models/sneaker.obj', 'models/sneaker.mtl', function(object) {

      object.scale.set(1, 1, 1);
      object.rotation.y = 600;
      object.rotation.z= 600;
      sneaker = object;
      scene.add(sneaker);
    });


  // var loader = new THREE.OBJLoader();
  // loader.load('models/sneaker.obj', function(object) {
  //   sneaker = object;
  //   sneaker.scale.set(1,1,1);
  //   sneaker.rotation.y = 600;
  //   sneaker.rotation.z= 600;
  //   scene.add(sneaker);

  // });





    renderer = new THREE.WebGLRenderer();
    renderer.setSize( WIDTH, HEIGHT );

    renderer.setClearColor(0x333F47, 1);


    var light = new THREE.PointLight(0xffffff);
    light.position.set(-100,200,100);
    scene.add(light);

    document.body.appendChild( renderer.domElement );

}

function animate() {

    requestAnimationFrame( animate );

    mesh.rotation.x += 0.01;
    mesh.rotation.y += 0.02;
    sneaker.rotation.x += 0.01;
    sneaker.rotation.y += 0.02;


    renderer.render( scene, camera );

}

})();

Answer 1

First a comment on your js : check if typeof sneaker !== 'undefined' in your render loop before asking to rotate your mesh, before loading it generates errors.

Your scene crashes because you are using too detailed materials, I can see a 4096x4096 bump map for instance. It strongly increases frame rendering time on desktop and is probably the reason why the page is irresponsive on mobile : the fragment shader computations become too big.

However it would be a shame to completly delete those details you spent time on. What you can do is to add a device detector in your js. You can use that to display two different models on desktop and on mobile.

But there are further important improvements you can bring. As they are part of my original post I let them there :) :

1. Resize your textures. You are using two 4096 x 4096 jpg of 4.5MB, this is heavy (note that there are webgl-enabled smartphones with only 500Mo RAM that get realeased these days). Moreover you have very few details that justifies it. You could change your uv to reduce a lot the parts with no details, and probably resize the picture to 512x512. Finally, use a JPG compressor that will reduce the weight by 70-80%. Depending on your picture PNG can be a better choice also. The device's GPU memory is still something else, and if you still need to improve performance you can check in the script if the client supports .pvr or .ktx texture formats, optimized for GPU memory.

2. An important problem that makes your visualization unappropriate for mobile devices is that you have ... 23 render calls, because you are using 15 textures and 23 geometries.

What it means is that, for each frame, you will have to bind 23 different geometries before the final frame renders. Some mobile CPU-GPU couples cannot do that 60 times per second. Don't plan more than 10 render calls for average mobile devices. That means less geometries with less materials. Merge.

I have not inspected your .obj file in detail to understand how you get 23 geometries in the end, neither where your 13 textures come from, up to you.

A lot of 3D apps (OpenGL) on the stores have more than 23 objects of course. But stores know the apps and they know your phone so they can do the compatibility job and hide the app to low devices.

Here is the tip to check your render calls, geometries and materials in the scene : in your main function, after having set the renderer , include a pointer to it in the window object window.renderer = renderer . Now at runtime in your console, once resources have been loaded, type renderer.info . It will return those data in an object.