ThreeJS 纹理从远处看时像素化 [英] ThreeJS Texture is pixelated when seen from distance

问题描述

我在玩 webGL 和 ThreeJS，然后我遇到了以下问题:

从远处看时，带有大图像的纹理会变得像素化.

检查示例:http://jsfiddle.net/4qTR3/1/>

代码如下:

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);场景.添加(光)；var light2 = new THREE.AmbientLight(0x444444);场景添加(light2)；var renderer = new THREE.WebGLRenderer({抗锯齿:真});renderer.setSize(window.innerWidth, window.innerHeight);document.body.appendChild(renderer.domElement);var geometry = new THREE.PlaneGeometry(500, 500, 10, 10);//我在我的项目中使用了不同的纹理var texture = new THREE.ImageUtils.loadTexture(TEST_IMAGE);var textureBack = new THREE.ImageUtils.loadTexture(TEST_IMAGE);textureBack.anisotropy = renderer.getMaxAnisotropy();纹理.各向异性 = renderer.getMaxAnisotropy();//过滤器纹理.magFilter = THREE.NearestFilter;texture.minFilter = THREE.LinearMipMapLinearFilter;textureBack.magFilter = THREE.NearestFilter;textureBack.minFilter = THREE.LinearMipMapLinearFilter;var 材料 = [新的 THREE.MeshLambertMaterial({透明:真实，地图:纹理，侧面:三.FrontSide}),新的 THREE.MeshLambertMaterial({透明:真实，地图:纹理返回，侧面:三.BackSide})];for (var i = 0, len = geometry.faces.length; i < len; i++) {var face = geometry.faces[i].clone();face.materialIndex = 1;几何.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;场景添加(平面对象)；相机.位置.z = 1000;(函数渲染(){请求动画帧(渲染)；planeObject.rotation.y += 0.02;renderer.render(场景，相机)；})();

如果纹理的图像中有文字，文字会变得非常像素化，质量很差.

我该如何解决这个问题?

解决方案

为了不像素化，您需要使用 mips，但 WebGL 无法为非 2 次幂的纹理生成 mips.您的纹理是 800x533，它们都不是 2 的幂.

几个选项

1) 将图片离线缩放到 2 的幂，如 512x512 或 1024x512

2) 在制作纹理之前在运行时缩放图片.

自己加载图像，加载后制作一个 2 次幂的画布.调用 drawImage(img, 0, 0, canvas.width, canvas.height) 将图像缩放到画布中.然后将画布加载到纹理中.

您可能还想将 mag 过滤从 NearestFilter 更改为 LinearFilter.

注意:(1) 是更好的选择.(2) 在用户机器上花费时间，使用更多内存，并且您无法保证缩放的质量.

此处示例.

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?

解决方案

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.

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