javascript - Three.js 中程序生成的凹凸贴图或镜面贴图？

Question

我知道使用 Three.js，您可以使用外部图像来定义凹凸贴图和镜面贴图:

var specular = THREE.ImageUtils.loadTexture("path/to/file.png");
var myMaterial = new THREE.MeshPhongMaterial();
myMaterial.specularMap = specular;

是否可以按程序创建凹凸贴图或镜面反射贴图？例如，也许您只需要 Material 上有一个随机的、凹凸不平的表面。您可以使用某种函数来随机创建此凹凸贴图以用于凹凸贴图或镜面反射贴图，而不必使用外部文件吗？

Answer 1

这非常简单。我做了一个 fiddle

http://jsfiddle.net/zs1bzkab/

generateNoise = function(opacity,canvas) {
   var
   x, y,
   number,
   opacity = opacity || .2;
     ctx = canvas.getContext('2d');
   for ( x = 0; x < canvas.width; x++ ) {
      for ( y = 0; y < canvas.height; y++ ) {
         number = Math.floor( Math.random() * 60 );

         ctx.fillStyle = "rgba(" + number + "," + number + "," + number + "," + opacity + ")";
         ctx.fillRect(x, y, 1, 1);
      }
   }
}



var mesh;
var scene = new THREE.Scene();

var camera = new THREE.PerspectiveCamera(50, 500 / 400, 0.1, 1000);
camera.position.z = 10;

var renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(500, 400);
document.body.appendChild(renderer.domElement);

var canvas = document.createElement("canvas");

canvas.width = 400;
canvas.height = 400;


generateNoise(.1, canvas);

var texture = new THREE.Texture(canvas);
texture.needsUpdate = true;

var geometry = new THREE.SphereGeometry(3, 50, 50, 0, Math.PI * 2, 0, Math.PI * 2);
var material = new THREE.MeshPhongMaterial({ map: texture, bumpMap: texture });

var light = new THREE.PointLight( new THREE.Color("rgb(255,70,3)"), 2.5);
var light2 = new THREE.PointLight( new THREE.Color("rgb(255,15,255)"), 4);
light.position.set( 0, -100, 800 );
light2.position.set( 50, 50, 900 );
mesh = new THREE.Mesh(geometry, material);

scene.add ( light );
scene.add ( light2 );
scene.add(mesh);

var render = function () {
    requestAnimationFrame(render);
    mesh.rotation.y += 0.01;
    renderer.render(scene, camera);
};

render();