ThreeJS Texture is pixelated when seen from distance

Question

I was playing with webGL and ThreeJS, then I've got the following issue:

Textures with large images gets pixelated when seen from distance.

Check the example: http://jsfiddle.net/4qTR3/1/

Below is the code:

    var scene = new THREE.Scene();
    var camera = new THREE.PerspectiveCamera(40, window.innerWidth / window.innerHeight, 10, 7000);

    var light = new THREE.PointLight(0xffffff);
    light.position.set(0, 150, 100);
    scene.add(light);

    var light2 = new THREE.AmbientLight(0x444444);
    scene.add(light2);

    var renderer = new THREE.WebGLRenderer({
        antialias: true
    });
    renderer.setSize(window.innerWidth, window.innerHeight);
    document.body.appendChild(renderer.domElement);

    var geometry = new THREE.PlaneGeometry(500, 500, 10, 10);

    //I use different textures in my project
    var texture = new THREE.ImageUtils.loadTexture(TEST_IMAGE);
    var textureBack = new THREE.ImageUtils.loadTexture(TEST_IMAGE);

    textureBack.anisotropy = renderer.getMaxAnisotropy();
    texture.anisotropy = renderer.getMaxAnisotropy();

    //Filters
    texture.magFilter = THREE.NearestFilter;
    texture.minFilter = THREE.LinearMipMapLinearFilter;
    textureBack.magFilter = THREE.NearestFilter;
    textureBack.minFilter = THREE.LinearMipMapLinearFilter;

    var materials = [
    new THREE.MeshLambertMaterial({
        transparent: true,
        map: texture,
        side: THREE.FrontSide
    }),
    new THREE.MeshLambertMaterial({
        transparent: true,
        map: textureBack,
        side: THREE.BackSide
    })];

    for (var i = 0, len = geometry.faces.length; i < len; i++) {
        var face = geometry.faces[i].clone();
        face.materialIndex = 1;
        geometry.faces.push(face);
        geometry.faceVertexUvs[0].push(geometry.faceVertexUvs[0][i].slice(0));
    }

    planeObject = new THREE.Mesh(geometry, new THREE.MeshFaceMaterial(materials));

    planeObject.overdraw = true;
    planeObject.position.z = -5000;

    scene.add(planeObject);

    camera.position.z = 1000;

    (function render() {
        requestAnimationFrame(render);
        planeObject.rotation.y += 0.02;
        renderer.render(scene, camera);
    })();

If the image of the texture has got text in it, the text becomes very pixelated with poor quality.

How can I fix this?

Answer 1

In order to not get pixelated you need to use mips but WebGL can't generate mips for non-power-of-2 textures. Your texture is 800x533, neither of those is a power of 2.

a couple of options

1) Scale the picture offline to powers of 2 like 512x512 or 1024x512

2) Scale the picture at runtime before making a texture.

Load the image yourself, once loaded make a canvas that is power-of-2. call drawImage(img, 0, 0, canvas.width, canvas.height) to scale the image into the canvas. Then load the canvas into a texture.

You also probably want to change your mag filtering from NearestFilter to LinearFilter.

Note: (1) is the better option. (2) takes time on the user's machine, uses more memory, and you have no guarantee what the quality of the scaling will be.

Example here.