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。
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