js实现一个弥红灯爱心流光动画效果代码-html代码-BFW代码库

js实现一个弥红灯爱心流光动画效果代码

代码语言：html

所属分类：动画

代码描述：js实现一个弥红灯爱心流光动画效果代码

下面为部分代码预览，完整代码请点击下载或在bfwstudio webide中打开

<html lang="en"><head>

  <meta charset="UTF-8">
  

<style>
body {
  background-color: #000;    
  margin: 0;
  overflow: hidden;
  background-repeat: no-repeat;
}
</style>



</head>

<body >
  
  <canvas id="canvas" width="918" height="286"></canvas>


  
      <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
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 = 1.3;
float radius = 0.008;

//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, di.........完整代码请登录后点击上方下载按钮下载查看