特效介绍
基于webgl和canvas的HTML5科技梦幻波浪动态线条特效动画背景代码，颜色随机，可设置颜色，颜色模式基于HSV。下面代码即是本插件的全部内容，所以就不提供下载地址了。
使用方法
1、在需要显示本canvas的地方加入下面代码，大小可自己设置，也可以用css定义：
<canvas width="1363" height="937" id="waves"></canvas>2、在页面底部加入下面的js
"use strict";
const webGL = {
init(options) {
this.elem = document.querySelector("#waves");
this.gl = (
this.elem.getContext("webgl", options) ||
this.elem.getContext("experimental-webgl", options)
);
if (!this.gl) return false;
const vertexShader = this.gl.createShader(this.gl.VERTEX_SHADER);
this.gl.shaderSource(vertexShader, `
precision highp float;
attribute vec2 aPosition;
uniform vec3 uHSV;
uniform vec2 uResolution;
varying vec4 vColor;
vec3 hsv2rgb(vec3 c) {
vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}
void main() {
gl_PointSize = 1.0;
gl_Position = vec4(
( aPosition.x / uResolution.x * 2.0) - 1.0,
(-aPosition.y / uResolution.y * 2.0) + 1.0,
0.0,
1.0
);
vColor = vec4(hsv2rgb(uHSV), 1.0);
}
`);
this.gl.compileShader(vertexShader);
const fragmentShader = this.gl.createShader(this.gl.FRAGMENT_SHADER);
this.gl.shaderSource(fragmentShader, `
precision highp float;
varying vec4 vColor;
void main() {
gl_FragColor = vColor;
}
`);
this.gl.compileShader(fragmentShader);
this.program = this.gl.createProgram();
this.gl.attachShader(this.program, vertexShader);
this.gl.attachShader(this.program, fragmentShader);
this.gl.linkProgram(this.program);
this.gl.useProgram(this.program);
this.aPosition = this.gl.getAttribLocation(this.program, "aPosition");
this.gl.enableVertexAttribArray(this.aPosition);
this.positionBuffer = this.gl.createBuffer();
this.uHSV = this.gl.getUniformLocation(this.program, "uHSV");
this.gl.enableVertexAttribArray(this.uHSV);
this.resize();
window.addEventListener("resize", () => this.resize(), false);
return this;
},
resize () {
this.width = this.elem.width = this.elem.offsetWidth;
this.height = this.elem.height = this.elem.offsetHeight;
const uResolution = this.gl.getUniformLocation(this.program, "uResolution");
this.gl.enableVertexAttribArray(uResolution);
this.gl.uniform2f(uResolution, this.width, this.height);
this.gl.viewport(0, 0,
this.gl.drawingBufferWidth,
this.gl.drawingBufferHeight
);
},
blend (s, d) {
this.gl.blendFunc(s, d);
this.gl.enable(this.gl.BLEND);
},
createBufferLine (len) {
this.num = len;
this.bufferLine = new Float32Array(len * 2);
},
beginPath () {
this.k = 0;
},
strokeStyle (h, s, v) {
this.gl.uniform3f(this.uHSV, h, s, v);
},
lineTo (x, y) {
this.bufferLine[this.k++] = x;
this.bufferLine[this.k++] = y;
},
stroke () {
this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.positionBuffer);
this.gl.vertexAttribPointer(this.aPosition, 2, this.gl.FLOAT, false, 0, 0);
this.gl.bufferData(
this.gl.ARRAY_BUFFER,
this.bufferLine,
this.gl.DYNAMIC_DRAW
);
this.gl.drawArrays(this.gl.LINE_STRIP, 0, this.num);
}
};
{
const perlin = {
init() {
this.p = new Uint8Array(512);
const p = new Uint8Array(256);
for (let i = 0; i < 256; i++) p[i] = i;
for (let i = 255; i > 0; i--) {
const n = Math.floor((i + 1) * Math.random());
[p[i], p[n]] = [p[n], p[i]];
}
for (let i = 0; i < 512; i++) this.p[i] = p[i & 255];
},
fade(t) {
return t * t * t * (t * (t * 6 - 15) + 10);
},
lerp(t, a, b) {
return a + t * (b - a);
},
grad(hash, x, y, z) {
const h = hash & 15;
const u = h < 8 ? x : y;
const v = h < 4 ? y : h == 12 || h == 14 ? x : z;
return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
},
noise(xi, yi, zi) {
const X = Math.floor(xi) & 255;
const Y = Math.floor(yi) & 255;
const Z = Math.floor(zi) & 255;
const x = xi - Math.floor(xi);
const y = yi - Math.floor(yi);
const z = zi - Math.floor(zi);
const u = this.fade(x);
const v = this.fade(y);
const w = this.fade(z);
const A = this.p[X] + Y;
const AA = this.p[A] + Z;
const AB = this.p[A + 1] + Z;
const B = this.p[X + 1] + Y;
const BA = this.p[B] + Z;
const BB = this.p[B + 1] + Z;
return this.lerp(
w,
this.lerp(
v,
this.lerp(u, this.grad(this.p[AA], x, y, z), this.grad(this.p[BA], x - 1, y, z)),
this.lerp(u, this.grad(this.p[AB], x, y - 1, z), this.grad(this.p[BB], x - 1, y - 1, z))
),
this.lerp(
v,
this.lerp(u, this.grad(this.p[AA + 1], x, y, z - 1), this.grad(this.p[BA + 1], x - 1, y, z - 1)),
this.lerp(
u,
this.grad(this.p[AB + 1], x, y - 1, z - 1),
this.grad(this.p[BB + 1], x - 1, y - 1, z - 1)
)
)
);
}
};
const canvas = webGL.init({
alpha: false,
stencil: false,
antialias: false,
depth: false,
});
canvas.blend(canvas.gl.ONE, canvas.gl.ONE);
perlin.init();
canvas.createBufferLine(100);
let z = 0;
function run() {
const sw = canvas.width / 100;
const sh = sw * 30;
for (let i = 0; i < 180; i++) {
canvas.beginPath();
canvas.strokeStyle(
z + i / 360,
0.5,
0.3
);
for (let j = -50; j < 50; j++) {
const h = perlin.noise(j * 0.05, z - i * 0.01, z);
canvas.lineTo(
canvas.width * 0.5 + 0.01 * (i + 180) * j * sw * 0.5,
-90 + i + canvas.height * 0.5 + h * sh
);
}
canvas.stroke();
}
z += 0.0025;
requestAnimationFrame(run);
}
run();
}
3、如果要修改颜色，可以在js代码中找到canvas.strokeStyle，修改里面的值，颜色模式为HSV。
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