bluring

README.md

bluring

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index.css

@import url("https://webglfundamentals.org/webgl/resources/webgl-tutorials.css");
body {
  margin: 0;
}
#canvas {
  width: 3000px;
  height: 3000px;
  display: block;
}

index.html

<canvas id="canvas"></canvas>
<!-- vertex shader -->
<script src="https://www.lactame.com/lib/image-js/0.21.2/image.min.js"></script>
<script  id="vertex-shader-2d" type="x-shader/x-vertex">
attribute vec2 a_position;
attribute vec2 a_texCoord;

uniform vec2 u_resolution;

varying vec2 v_texCoord;

void main() {
   // convert the rectangle from pixels to 0.0 to 1.0
   vec2 zeroToOne = a_position / u_resolution;

   // convert from 0->1 to 0->2
   vec2 zeroToTwo = zeroToOne * 2.0;

   // convert from 0->2 to -1->+1 (clipspace)
   vec2 clipSpace = zeroToTwo - 1.0;

   gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);

   // pass the texCoord to the fragment shader
   // The GPU will interpolate this value between points.
   v_texCoord = a_texCoord;
}
</script>
<!-- fragment shader -->
<script  id="fragment-shader-2d" type="x-shader/x-fragment">
precision highp float;

// our textures
uniform sampler2D inputa;
uniform sampler2D zdepth;
uniform float width;
uniform float height;

// the texCoords passed in from the vertex shader.
varying vec2 v_texCoord;

vec4 getColor(vec2 p, float dx, float dy) {
  vec2 coord = vec2(p.x + dx / width, p.y + dy / height);
  return texture2D(inputa, coord);
}

void main() {
  vec4 result = getColor(v_texCoord, 0.0, 0.0);
  float zdepthu = texture2D(zdepth, v_texCoord).r;
  float Size = (1.0 - zdepthu) * 7.0 - 0.5;
  float weight = 1.0;
  if (Size > 0.0) {
    float sigma = Size;
    for (float dx = -10.0; dx <= 10.0; dx += 1.0) {
      for (float dy = -10.0; dy <= 10.0; dy += 1.0) {
        float w = 1.0 / sqrt(6.28 * sigma * sigma) * exp(- (dx * dx + dy * dy) / (2.0 * sigma * sigma));
        result += w * getColor(v_texCoord, dx, dy);
        weight += w;
      }
    }
    result /= weight;
  }
  gl_FragColor = result; //vec4(zdepthu, zdepthu, zdepthu, 1);
}
</script>
<script src="https://webglfundamentals.org/webgl/resources/webgl-utils.js"></script>
<script src="https://twgljs.org/dist/4.x/twgl-full.min.js"></script>
<script src="https://www.lactame.com/lib/image-js/0.21.2/image.min.js"></script>

index.js

"use strict";
const assets = {
  input: 'https://res.cloudinary.com/casestry-com/image/upload/v1677099413/test/download_4_yszcgh.png',
  zdepth: 'https://res.cloudinary.com/casestry-com/image/upload/v1677092667/test/zdepth_vnhyk4.png',
}

async function loadImage(url) {
  return new Promise((resolve) => {
    var image = new Image();
    requestCORSIfNotSameOrigin(image, url)
    image.src = url;
    image.onload = () => {
      resolve(image)
    };
  })
}


async function main() {
  const input = await loadImage(assets.input)
  const zdepth = await loadImage(assets.zdepth);
  render([input, zdepth])
}

var documentCanvas = document.querySelector('#canvas');

function render(images) {
  var starttime = Date.now();
  // Get A WebGL context
  /** @type {HTMLCanvasElement} */
  var canvas = document.createElement("canvas");
  canvas = documentCanvas;
  canvas.width = images[1].width;
  canvas.height = images[1].height;

  var gl = canvas.getContext("webgl");
  if (!gl) {
    return;
  }

  // setup GLSL program
  var program = twgl.createProgramFromScripts(gl, ["vertex-shader-2d", "fragment-shader-2d"]);
  gl.useProgram(program);

  // look up where the vertex data needs to go.
  var positionLocation = gl.getAttribLocation(program, "a_position");
  var texcoordLocation = gl.getAttribLocation(program, "a_texCoord");

  // Create a buffer to put three 2d clip space points in
  var positionBuffer = gl.createBuffer();

  // Bind it to ARRAY_BUFFER (think of it as ARRAY_BUFFER = positionBuffer)
  gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
  // Set a rectangle the same size as the image.

  setRectangle(gl, 0, 0, canvas.width, canvas.height);

  // provide texture coordinates for the rectangle.
  var texcoordBuffer = gl.createBuffer();
  gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
      0.0,  0.0,
      1.0,  0.0,
      0.0,  1.0,
      0.0,  1.0,
      1.0,  0.0,
      1.0,  1.0,
  ]), gl.STATIC_DRAW);

  // create 2 textures
  var textures = [];
  for (var ii = 0; ii < 2; ++ii) {
    var texture = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, texture);

    // Set the parameters so we can render any size image.
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);

    // Upload the image into the texture.
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, images[ii]);

    // add the texture to the array of textures.
    textures.push(texture);
  }

  // lookup uniforms
  var resolutionLocation = gl.getUniformLocation(program, "u_resolution");

  // lookup the sampler locations.
  var inputLocation = gl.getUniformLocation(program, "inputa");
  var zdepthLocation = gl.getUniformLocation(program, "zdepth");
  var widthLocation = gl.getUniformLocation(program, "width");
  var heightLocation = gl.getUniformLocation(program, "height");

  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

  // Clear the canvas
  gl.clearColor(0, 0, 0, 0);
  gl.clear(gl.COLOR_BUFFER_BIT);

  // Tell it to use our program (pair of shaders)
  gl.useProgram(program);

  // Turn on the position attribute
  gl.enableVertexAttribArray(positionLocation);

  // Bind the position buffer.
  gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);

  // Tell the position attribute how to get data out of positionBuffer (ARRAY_BUFFER)
  var size = 2;          // 2 components per iteration
  var type = gl.FLOAT;   // the data is 32bit floats
  var normalize = false; // don't normalize the data
  var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
  var offset = 0;        // start at the beginning of the buffer
  gl.vertexAttribPointer(
      positionLocation, size, type, normalize, stride, offset);

  // Turn on the texcoord attribute
  gl.enableVertexAttribArray(texcoordLocation);

  // bind the texcoord buffer.
  gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);

  // Tell the texcoord attribute how to get data out of texcoordBuffer (ARRAY_BUFFER)
  var size = 2;          // 2 components per iteration
  var type = gl.FLOAT;   // the data is 32bit floats
  var normalize = false; // don't normalize the data
  var stride = 0;        // 0 = move forward size * sizeof(type) each iteration to get the next position
  var offset = 0;        // start at the beginning of the buffer
  gl.vertexAttribPointer(
      texcoordLocation, size, type, normalize, stride, offset);

  // set the resolution
  gl.uniform2f(resolutionLocation, gl.canvas.width, gl.canvas.height);

  // set which texture units to render with.
  gl.uniform1i(inputLocation, 0);  // texture unit 0
  gl.uniform1i(zdepthLocation, 1);  // texture unit 1

  gl.uniform1f(widthLocation, gl.canvas.width);  // texture unit 3
  gl.uniform1f(heightLocation, gl.canvas.height);  // texture unit 4

  // Set each texture unit to use a particular texture.
  gl.activeTexture(gl.TEXTURE0);
  gl.bindTexture(gl.TEXTURE_2D, textures[0]);
  gl.activeTexture(gl.TEXTURE1);
  gl.bindTexture(gl.TEXTURE_2D, textures[1]);
  gl.activeTexture(gl.TEXTURE2);
  gl.bindTexture(gl.TEXTURE_2D, textures[2]);
  gl.activeTexture(gl.TEXTURE3);
  gl.bindTexture(gl.TEXTURE_2D, textures[3]);

  // Draw the rectangle.
  gl.drawArrays(gl.TRIANGLES, 0, 6);

  console.log('Elapsed: ', Date.now() - starttime);

}

function setRectangle(gl, x, y, width, height) {
  var x1 = x;
  var x2 = x + width;
  var y1 = y;
  var y2 = y + height;
  gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([
     x1, y1,
     x2, y1,
     x1, y2,
     x1, y2,
     x2, y1,
     x2, y2,
  ]), gl.STATIC_DRAW);
}

main();

// This is needed if the images are not on the same domain
// NOTE: The server providing the images must give CORS permissions
// in order to be able to use the image with WebGL. Most sites
// do NOT give permission.
// See: https://webglfundamentals.org/webgl/lessons/webgl-cors-permission.html
function requestCORSIfNotSameOrigin(img, url) {
  if ((new URL(url, window.location.href)).origin !== window.location.origin) {
    img.crossOrigin = "";
  }
}

jsGist.json

{"name":"bluring","settings":{},"filenames":["index.html","index.css","index.js"]}