three.js 将图片马赛克化

2020-08-31 15:45:03 浏览数 (2)

这篇郭先生来说说BufferGeometry,类型化数组和粒子系统的使用,并且让图片有马赛克效果(同理可以让不清晰的图片清晰化),如图所示。在线案例点击图片马赛克。

1. 解析图片

解析图片和上一篇一样

代码语言:javascript复制
initCanvas() {
    canvas = document.createElement('canvas');
    content = canvas.getContext('2d');
    canvas.width = 1600;
    canvas.height = 1200;
    img = new Image();
    img.crossOrigin = '*';
    img.src = "/static/images/base/girl.jpg";
    img.onload = () => {
        content.drawImage(img, 0, 0, canvas.width, canvas.height);
        imgDate = content.getImageData(0, 0, canvas.width, canvas.height);
        this.createPotCloud();   //创建点云
    };
}

2. 操作像素点

代码语言:javascript复制
createPotCloud() {
    if (points) {
        scene.remove(points)
    }
    let cw = Math.floor(canvas.width / size);
    let ch = Math.floor(canvas.height / size);
    particles = cw * ch;
    geometry = new THREE.BufferGeometry();
    positions = new Float32Array(Math.floor(particles * 3));
    positions_af = new Float32Array(Math.floor(particles * 3));
    var colors = new Float32Array(Math.floor(particles * 3));
    for (var i = 0; i < positions.length; i  = 1) {

        positions[3 * i] = - canvas.width / 2   (i % cw) * size;
        positions[3 * i   1] = canvas.height / 2   Math.floor((-1 - i) / cw) * size;
        positions[3 * i   2] = 0;

        let selectPos = size * (i % cw)   Math.floor(i / cw) * cw * size * size;
        colors[3 * i] = imgDate.data[4 * selectPos] / 255.0;
        colors[3 * i   1] = imgDate.data[4 * selectPos   1] / 255.0;
        colors[3 * i   2] = imgDate.data[4 * selectPos   2] / 255.0;
    }
    geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));
    geometry.setAttribute('color', new THREE.BufferAttribute(colors, 3))
    geometry.dynamic = true;
    geometry.attributes.position.needsUpdate = true;
    var material = new THREE.PointsMaterial({ size: size, vertexColors: THREE.VertexColors })
    points = new THREE.Points(geometry, material);
    points.name = 'points';
    scene.add(points);
    loaded = true;
},

可以不用纠结代码,核心思想其实我们只需要每隔一定的颜色点取出一个颜色点,然后将这个颜色赋予到geometry的color属性上,就可以了,也可以每隔两行、两列取一个点,但是图片上面的点是一维的,所以需要一些数学方法,

如图所示,原理很简单哦。将不清晰的图片清晰化,就是需要插入更多的像素点,插入的像素点,需要根据已存在的像素点的颜色进行插值,比如原图的像素点1为0xffffff,像素点2的颜色为0xdddddd,则插在两个像素点之间像素点的颜色为0xeeeeee,以此类推。

转载请注明地址:郭先生的博客

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