HTML流光爱心 - 技术栈

文章目录

|----|--------------------------------------------------------------------------------------------------------------|
| 序号 | 目录 |
| 1 | HTML满屏跳动的爱心（可写字） |
| 2 | HTML五彩缤纷的爱心 |
| 3 | HTML满屏漂浮爱心 |
| 4 | HTML情人节快乐 |
| 5 | HTML蓝色爱心射线 |
| 6 | HTML跳动的爱心（简易版） |
| 7 | HTML粒子爱心 |
| 8 | HTML蓝色动态爱心 |
| 9 | HTML跳动的爱心（双心版） |
| 10 | HTML橙色动态粒子爱心 |
| 11 | HTML旋转爱心 |
| 12 | HTML爱情树 |
| 13 | HTML3D相册 |
| 14 | HTML旋转相册 |
| 15 | HTML基础烟花秀 |
| 16 | HTML炫酷烟花秀 |
| 17 | HTML粉色烟花秀 |
| 18 | HTML新春烟花 |
| 19 | HTML龙年大吉 |
| 20 | HTML圣诞树 |
| 21 | HTML大雪纷飞 |
| 22 | HTML想见你 |
| 23 | HTML元素周期表 |
| 24 | HTML飞舞的花瓣 |
| 25 | HTML星空特效 |
| 26 | HTML黑客帝国字母雨 |
| 27 | HTML哆啦A梦 |
| 28 | HTML流星雨 |
| 29 | HTML沙漏爱心 |
| 30 | HTML爱心字母雨 |
| 31 | HTML爱心流星雨 |
| 32 | HTML生日蛋糕 |
| 33 | HTML流光爱心 |

写在前面

本期博主给大家推荐一个由HTML代码实现的、红蓝色线条组成的流光爱心，一起来看看吧。

完整代码

html 复制代码

<!DOCTYPE html>
<!--<div class="menu__subheader"><br>微信公众号：雁卿雁卿呀-->
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>流光爱心</title>
  <meta name="author" content="Logical Digit">
  </head>
      <!-- css部分 -->
 <style>
  body {
    background-color: #000;
    margin: 0;
    overflow: hidden;
    background-repeat: no-repeat;
}
</style>
  <body>
    <!-- 绘画爱心 -->
    <canvas id="canvas" width="1400" height="600"></canvas>
    <!-- js部分 -->
  </body>
  <script>
var canvas = document.getElementById("canvas");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
// Initialize the GL context
var gl = canvas.getContext('webgl');
if (!gl) {
    console.error("Unable to initialize WebGL.");
}
//Time step
var dt = 0.015;
//Time
var time = 0.0;
//************** Shader sources **************
var vertexSource = `
attribute vec2 position;
void main() {
  gl_Position = vec4(position, 0.0, 1.0);
}
`;
 
var fragmentSource = `
precision highp float;
uniform float width;
uniform float height;
vec2 resolution = vec2(width, height);
uniform float time;
#define POINT_COUNT 8
vec2 points[POINT_COUNT];
const float speed = -0.5;
const float len = 0.25;
float intensity = 0.9;
float radius = 0.015;
//https://www.shadertoy.com/view/MlKcDD
//Signed distance to a quadratic bezier
float sdBezier(vec2 pos, vec2 A, vec2 B, vec2 C){    
  vec2 a = B - A;
  vec2 b = A - 2.0*B + C;
  vec2 c = a * 2.0;
  vec2 d = A - pos;
  float kk = 1.0 / dot(b,b);
  float kx = kk * dot(a,b);
  float ky = kk * (2.0*dot(a,a)+dot(d,b)) / 3.0;
  float kz = kk * dot(d,a);      
  float res = 0.0;
  float p = ky - kx*kx;
  float p3 = p*p*p;
  float q = kx*(2.0*kx*kx - 3.0*ky) + kz;
  float h = q*q + 4.0*p3;
  if(h >= 0.0){ 
    h = sqrt(h);
    vec2 x = (vec2(h, -h) - q) / 2.0;
    vec2 uv = sign(x)*pow(abs(x), vec2(1.0/3.0));
    float t = uv.x + uv.y - kx;
    t = clamp( t, 0.0, 1.0 );
    // 1 root
    vec2 qos = d + (c + b*t)*t;
    res = length(qos);
  }else{
    float z = sqrt(-p);
    float v = acos( q/(p*z*2.0) ) / 3.0;
    float m = cos(v);
    float n = sin(v)*1.732050808;
    vec3 t = vec3(m + m, -n - m, n - m) * z - kx;
    t = clamp( t, 0.0, 1.0 );
    // 3 roots
    vec2 qos = d + (c + b*t.x)*t.x;
    float dis = dot(qos,qos);
        
    res = dis;
    qos = d + (c + b*t.y)*t.y;
    dis = dot(qos,qos);
    res = min(res,dis);
    
    qos = d + (c + b*t.z)*t.z;
    dis = dot(qos,qos);
    res = min(res,dis);
    res = sqrt( res );
  }
    
  return res;
}
//http://mathworld.wolfram.com/HeartCurve.html
vec2 getHeartPosition(float t){
  return vec2(16.0 * sin(t) * sin(t) * sin(t),
              -(13.0 * cos(t) - 5.0 * cos(2.0*t)
              - 2.0 * cos(3.0*t) - cos(4.0*t)));
}
//https://www.shadertoy.com/view/3s3GDn
float getGlow(float dist, float radius, float intensity){
  return pow(radius/dist, intensity);
}
float getSegment(float t, vec2 pos, float offset, float scale){
  for(int i = 0; i < POINT_COUNT; i++){
    points[i] = getHeartPosition(offset + float(i)*len + fract(speed * t) * 6.28);
  }
    
  vec2 c = (points[0] + points[1]) / 2.0;
  vec2 c_prev;
  float dist = 10000.0;
    
  for(int i = 0; i < POINT_COUNT-1; i++){
    //https://tinyurl.com/y2htbwkm
    c_prev = c;
    c = (points[i] + points[i+1]) / 2.0;
    dist = min(dist, sdBezier(pos, scale * c_prev, scale * points[i], scale * c));
  }
  return max(0.0, dist);
}
void main(){
  vec2 uv = gl_FragCoord.xy/resolution.xy;
  float widthHeightRatio = resolution.x/resolution.y;
  vec2 centre = vec2(0.5, 0.5);
  vec2 pos = centre - uv;
  pos.y /= widthHeightRatio;
  //Shift upwards to centre heart
  pos.y += 0.02;
  float scale = 0.000015 * height;
  
  float t = time;
    
  //Get first segment
  float dist = getSegment(t, pos, 0.0, scale);
  float glow = getGlow(dist, radius, intensity);
    
  vec3 col = vec3(0.0);
    
  //White core
  col += 10.0*vec3(smoothstep(0.003, 0.001, dist));
  //Pink glow
  col += glow * vec3(0.94,0.14,0.4);
    
  //Get second segment
  dist = getSegment(t, pos, 3.4, scale);
  glow = getGlow(dist, radius, intensity);
    
  //White core
  col += 10.0*vec3(smoothstep(0.003, 0.001, dist));
  //Blue glow
  col += glow * vec3(0.2,0.6,1.0);
        
  //Tone mapping
  col = 1.0 - exp(-col);
  //Output to screen
   gl_FragColor = vec4(col,1.0);
}
`;
 
//************** Utility functions **************
 
window.addEventListener('resize', onWindowResize, false);
 
function onWindowResize() {
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
    gl.viewport(0, 0, canvas.width, canvas.height);
    gl.uniform1f(widthHandle, window.innerWidth);
    gl.uniform1f(heightHandle, window.innerHeight);
}
 
 
//Compile shader and combine with source
function compileShader(shaderSource, shaderType) {
    var shader = gl.createShader(shaderType);
    gl.shaderSource(shader, shaderSource);
    gl.compileShader(shader);
    if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
        throw "Shader compile failed with: " + gl.getShaderInfoLog(shader);
    }
    return shader;
}
 
//From https://codepen.io/jlfwong/pen/GqmroZ
//Utility to complain loudly if we fail to find the attribute/uniform
function getAttribLocation(program, name) {
    var attributeLocation = gl.getAttribLocation(program, name);
    if (attributeLocation === -1) {
        throw 'Cannot find attribute ' + name + '.';
    }
    return attributeLocation;
}
 
function getUniformLocation(program, name) {
    var attributeLocation = gl.getUniformLocation(program, name);
    if (attributeLocation === -1) {
        throw 'Cannot find uniform ' + name + '.';
    }
    return attributeLocation;
}
 
//************** Create shaders **************
 
//Create vertex and fragment shaders
var vertexShader = compileShader(vertexSource, gl.VERTEX_SHADER);
var fragmentShader = compileShader(fragmentSource, gl.FRAGMENT_SHADER);
 
//Create shader programs
var program = gl.createProgram();
gl.attachShader(program, vertexShader);
gl.attachShader(program, fragmentShader);
gl.linkProgram(program);
 
gl.useProgram(program);
 
//Set up rectangle covering entire canvas 
var vertexData = new Float32Array([-1.0, 1.0, // top left
    -1.0, -1.0, // bottom left
    1.0, 1.0, // top right
    1.0, -1.0, // bottom right
]);
 
//Create vertex buffer
var vertexDataBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vertexDataBuffer);
gl.bufferData(gl.ARRAY_BUFFER, vertexData, gl.STATIC_DRAW);
 
// Layout of our data in the vertex buffer
var positionHandle = getAttribLocation(program, 'position');
 
gl.enableVertexAttribArray(positionHandle);
gl.vertexAttribPointer(positionHandle,
    2, // position is a vec2 (2 values per component)
    gl.FLOAT, // each component is a float
    false, // don't normalize values
    2 * 4, // two 4 byte float components per vertex (32 bit float is 4 bytes)
    0 // how many bytes inside the buffer to start from
);
 
//Set uniform handle
var timeHandle = getUniformLocation(program, 'time');
var widthHandle = getUniformLocation(program, 'width');
var heightHandle = getUniformLocation(program, 'height');
 
gl.uniform1f(widthHandle, window.innerWidth);
gl.uniform1f(heightHandle, window.innerHeight);
 
function draw() {
    //Update time
    time += dt;
 
    //Send uniforms to program
    gl.uniform1f(timeHandle, time);
    //Draw a triangle strip connecting vertices 0-4
    gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
 
    requestAnimationFrame(draw);
}
 
draw();
</script>
</html>

代码分析

这段代码通过HTML、CSS和WebGL结合实现了一个"流光爱心"效果，以下是对其的详细分析。

1. HTML结构

在HTML部分，主要是一个canvas元素，它是用于绘制心形动画的区域。canvas元素通过其ID属性canvas在JavaScript中被引用，用于初始化WebGL上下文。

<canvas id="canvas" width="1400" height="600"></canvas>

在这里，宽度和高度只是初始设置，代码通过JavaScript调整canvas的大小以适应浏览器窗口。

2. CSS部分

CSS的作用是设置整个网页的背景颜色为黑色，并使画布占据整个窗口，同时禁用滚动条以确保效果全屏展示。

html 复制代码

body {

    background-color: #000;
    margin: 0;
    overflow: hidden;
    background-repeat: no-repeat;
}

3. WebGL上下文初始化

JavaScript部分通过getContext('webgl')获取WebGL绘图上下文，这是一种用于在网页中绘制2D和3D图形的API。

html 复制代码

var canvas = document.getElementById("canvas");
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
var gl = canvas.getContext('webgl');
if (!gl) {
    console.error("Unable to initialize WebGL.");
}

这段代码确保WebGL能够正常运行，如果无法初始化WebGL，会在控制台输出错误信息。

4. 着色器程序

代码中定义了顶点着色器和片段着色器，用于处理图形的顶点和颜色计算。顶点着色器vertexSource负责定义绘制区域，而片段着色器fragmentSource则负责生成心形动画的光效。

顶点着色器 ：这个简单的顶点着色器只定义了矩形区域，覆盖整个canvas。

html 复制代码

attribute vec2 position;
void main() {
  gl_Position = vec4(position, 0.0, 1.0);
}

片段着色器 ：这是核心部分，计算并绘制了心形的流光效果。着色器使用了多种图形技术，如二次贝塞尔曲线距离函数来生成心形轮廓，getGlow函数实现光晕效果，getHeartPosition函数计算心形轨迹。

html 复制代码

vec2 getHeartPosition(float t){
  return vec2(16.0 * sin(t) * sin(t) * sin(t),
              -(13.0 * cos(t) - 5.0 * cos(2.0*t)
              - 2.0 * cos(3.0*t) - cos(4.0*t)));
}

这个公式是数学中的经典"心形曲线公式"，通过调整时间参数t，可以得到心形轨迹上的点。

5. 动态渲染

在draw函数中，程序使用requestAnimationFrame(draw)不断调用自己来实现帧动画，逐帧更新time变量，使得心形的流光效果随着时间变化而持续运行。

html 复制代码

function draw() {
    time += dt;
    gl.uniform1f(timeHandle, time);
    gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
    requestAnimationFrame(draw);
}

每一帧，WebGL都会根据当前的时间time重新计算心形上每个点的位置，进而生成流光效果。

6. 响应窗口变化

代码监听了窗口大小的变化，使用onWindowResize函数动态调整画布的大小，确保动画始终适应窗口尺寸，并且心形保持居中显示。

html 复制代码

window.addEventListener('resize', onWindowResize, false);
function onWindowResize() {
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;
    gl.viewport(0, 0, canvas.width, canvas.height);
    gl.uniform1f(widthHandle, window.innerWidth);
    gl.uniform1f(heightHandle, window.innerHeight);
}

总结

这段代码通过WebGL技术生成了一个心形流光效果。核心部分在于数学公式计算出的心形轨迹和光晕效果，通过着色器来实现。WebGL的强大之处在于它能直接操控GPU，生成高效的动画效果。

写在后面

我是一只有趣的兔子，感谢你的喜欢！