Love Heart Animation Using HTML and CSS Code
Published: 2023-05-13 07:15:19

 Welcome to the Codewithrandom blog. In this blog, We learn how to create an **[Heart Animation ](https://www.codewithrandom.com/2023/01/14/heart-icon-html-love-heart-animation-by-html-css-codewithrandom/)**Using HTML and CSS. In this Project, we have an Animated Heart with a Neon Glowing effect. by the end of this project, you learn how to create a Heart animation with the help of Html, Css, and JavaScript.


I hope you enjoy our blog so let's start with a basic html structure code for a I Love You.

## HTML Code For Love Animation:-
```
<body>
  <canvas id="canvas" width="1400" height="600"></canvas>
</body>
```

There is all the html code for the I Love You animation. we use canvas tags with a width of 1400 and a height is 600. you get only blank output with this code because we create only the structure of love animation.

Now, you can see output without Css and JavaScript. Then we write Css for styling Love animation and use javascript for making this extreme-level animation project.

## CSS Code For Heart Animation:-
```
body {
  background-color: #000;    
  margin: 0;
  overflow: hidden;
  background-repeat: no-repeat;
}
```
We use only body tag Css, we style canvas with javascript.

## Heart Animation JavaScript Code:-
```
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, dist));
  //Pink glow
  col += glow * vec3(1.0,0.05,0.3);
  
  //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(0.1,0.4,1.0);
        
	//Tone mapping
	col = 1.0 - exp(-col);

	//Gamma
	col = pow(col, vec3(0.4545));

	//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);

var lastFrame = Date.now();
var thisFrame;

function draw(){
	
  //Update time
	thisFrame = Date.now();
  time += (thisFrame - lastFrame)/1000;	
	lastFrame = thisFrame;

	//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();
```

 Hope you as the **[Heart Animation](https://www.codewithrandom.com/2023/01/14/heart-icon-html-love-heart-animation-by-html-css-codewithrandom/)**( I Love You animation). you can see the output  project screenshots. See our other blogs and gain knowledge in front-end development.

Thank you! 

If we made a mistake or any confusion, please drop a comment to reply or help you in easy learning.


Written by - Code With Random/Anki