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WebGL Month. Day 7. A bit of cleanup and tooling

lesnitsky profile image Andrei Lesnitsky Updated on ・5 min read

Tooling and refactor

This is a series of blog posts related to WebGL. New post will be available every day

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Hey 👋

Welcome to the WebGL month.

Since our codebase grows and will keep getting more complicated, we need some tooling and cleanup.

We'll need webpack, so let's create package.json and install it

📄 package.json

{
  "name": "webgl-month",
  "version": "1.0.0",
  "description": "Daily WebGL tutorials",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "repository": {
    "type": "git",
    "url": "git+https://github.com/lesnitsky/webgl-month.git"
  },
  "author": "",
  "license": "ISC",
  "bugs": {
    "url": "https://github.com/lesnitsky/webgl-month/issues"
  },
  "homepage": "https://github.com/lesnitsky/webgl-month#readme",
  "devDependencies": {
    "webpack": "^4.35.2",
    "webpack-cli": "^3.3.5"
  }
}

We'll need a simple webpack config

📄 webpack.config.js

const path = require('path');

module.exports = {
    entry: {
        'week-1': './src/week-1.js',
    },

    output: {
        path: path.resolve(__dirname, 'dist'),
        filename: '[name].js',
    },

    mode: 'development',
};

and update script source

📄 index.html

    </head>
    <body>
      <canvas></canvas>
-     <script src="./src/webgl-hello-world.js"></script>
+     <script src="./dist/week-1.js"></script>
    </body>
  </html>

Since shaders are raw strings, we can store shader source in separate file and use raw-loader for webpack.

📄 package.json

    },
    "homepage": "https://github.com/lesnitsky/webgl-month#readme",
    "devDependencies": {
+     "raw-loader": "^3.0.0",
      "webpack": "^4.35.2",
      "webpack-cli": "^3.3.5"
    }

📄 webpack.config.js

          filename: '[name].js',
      },

+     module: {
+         rules: [
+             {
+                 test: /\.glsl$/,
+                 use: 'raw-loader',
+             },
+         ],
+     },
+ 
      mode: 'development',
  };

and let's actually move shaders to separate files

📄 src/shaders/fragment.glsl

precision mediump float;

varying vec4 vColor;

void main() {
    gl_FragColor = vColor / 255.0;
    gl_FragColor.a = 1.0;
}

📄 src/shaders/vertex.glsl

attribute vec2 position;
attribute vec4 color;
uniform vec2 resolution;

varying vec4 vColor;

#define M_PI 3.1415926535897932384626433832795

void main() {
    vec2 transformedPosition = position / resolution * 2.0 - 1.0;
    gl_PointSize = 2.0;
    gl_Position = vec4(transformedPosition, 0, 1);

    vColor = color;
}

📄 src/week-1.js

+ import vShaderSource from './shaders/vertex.glsl';
+ import fShaderSource from './shaders/fragment.glsl';
+ 
  const canvas = document.querySelector('canvas');
  const gl = canvas.getContext('webgl');

  const vertexShader = gl.createShader(gl.VERTEX_SHADER);
  const fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);

- const vShaderSource = `
- attribute vec2 position;
- attribute vec4 color;
- uniform vec2 resolution;
- 
- varying vec4 vColor;
- 
- #define M_PI 3.1415926535897932384626433832795
- 
- void main() {
-     vec2 transformedPosition = position / resolution * 2.0 - 1.0;
-     gl_PointSize = 2.0;
-     gl_Position = vec4(transformedPosition, 0, 1);
- 
-     vColor = color;
- }
- `;
- 
- const fShaderSource = `
-     precision mediump float;
- 
-     varying vec4 vColor;
- 
-     void main() {
-         gl_FragColor = vColor / 255.0;
-         gl_FragColor.a = 1.0;
-     }
- `;
- 
  function compileShader(shader, source) {
      gl.shaderSource(shader, source);
      gl.compileShader(shader);

We can also move functions which create vertices positions to separate file

📄 src/shape-helpers.js

export function createRect(top, left, width, height) {
    return [
        left, top, // x1 y1
        left + width, top, // x2 y2
        left, top + height, // x3 y3
        left + width, top + height, // x4 y4
    ];
}

export function createHexagon(centerX, centerY, radius, segmentsCount) {
    const vertexData = [];
    const segmentAngle =  Math.PI * 2 / (segmentsCount - 1);

    for (let i = 0; i < Math.PI * 2; i += segmentAngle) {
        const from = i;
        const to = i + segmentAngle;

        const color = rainbowColors[i / segmentAngle];

        vertexData.push(centerX, centerY);
        vertexData.push(...color);

        vertexData.push(centerX + Math.cos(from) * radius, centerY + Math.sin(from) * radius);
        vertexData.push(...color);

        vertexData.push(centerX + Math.cos(to) * radius, centerY + Math.sin(to) * radius);
        vertexData.push(...color);
    }

    return vertexData;
}

📄 src/week-1.js

  import vShaderSource from './shaders/vertex.glsl';
  import fShaderSource from './shaders/fragment.glsl';

+ import { createRect } from './shape-helpers';
+ 
+ 
  const canvas = document.querySelector('canvas');
  const gl = canvas.getContext('webgl');


  const triangles = createRect(0, 0, canvas.height, canvas.height);

- function createRect(top, left, width, height) {
-     return [
-         left, top, // x1 y1
-         left + width, top, // x2 y2
-         left, top + height, // x3 y3
-         left + width, top + height, // x4 y4
-     ];
- }
- 
- function createHexagon(centerX, centerY, radius, segmentsCount) {
-     const vertexData = [];
-     const segmentAngle =  Math.PI * 2 / (segmentsCount - 1);
- 
-     for (let i = 0; i < Math.PI * 2; i += segmentAngle) {
-         const from = i;
-         const to = i + segmentAngle;
- 
-         const color = rainbowColors[i / segmentAngle];
- 
-         vertexData.push(centerX, centerY);
-         vertexData.push(...color);
- 
-         vertexData.push(centerX + Math.cos(from) * radius, centerY + Math.sin(from) * radius);
-         vertexData.push(...color);
- 
-         vertexData.push(centerX + Math.cos(to) * radius, centerY + Math.sin(to) * radius);
-         vertexData.push(...color);
-     }
- 
-     return vertexData;
- }
- 
  function fillWithColors(segmentsCount) {
      const colors = [];


Since we're no longer using color attribute, we can drop everyhting related to it

📄 src/shaders/fragment.glsl

  precision mediump float;

- varying vec4 vColor;
- 
  void main() {
-     gl_FragColor = vColor / 255.0;
-     gl_FragColor.a = 1.0;
+     gl_FragColor = vec4(1, 0, 0, 1);
  }

📄 src/shaders/vertex.glsl

  attribute vec2 position;
- attribute vec4 color;
  uniform vec2 resolution;

- varying vec4 vColor;
- 
  #define M_PI 3.1415926535897932384626433832795

  void main() {
      vec2 transformedPosition = position / resolution * 2.0 - 1.0;
      gl_PointSize = 2.0;
      gl_Position = vec4(transformedPosition, 0, 1);
- 
-     vColor = color;
  }

📄 src/week-1.js


  import { createRect } from './shape-helpers';

- 
  const canvas = document.querySelector('canvas');
  const gl = canvas.getContext('webgl');

  gl.useProgram(program);

  const positionLocation = gl.getAttribLocation(program, 'position');
- const colorLocation = gl.getAttribLocation(program, 'color');
- 
  const resolutionUniformLocation = gl.getUniformLocation(program, 'resolution');

  gl.uniform2fv(resolutionUniformLocation, [canvas.width, canvas.height]);

- const rainbowColors = [
-     [255, 0.0, 0.0, 255], // red
-     [255, 165, 0.0, 255], // orange
-     [255, 255, 0.0, 255], // yellow
-     [0.0, 255, 0.0, 255], // green
-     [0.0, 101, 255, 255], // skyblue
-     [0.0, 0.0, 255, 255], // blue,
-     [128, 0.0, 128, 255], // purple
- ];
- 
  const triangles = createRect(0, 0, canvas.height, canvas.height);

- function fillWithColors(segmentsCount) {
-     const colors = [];
- 
-     for (let i = 0; i < segmentsCount; i++) {
-         for (let j = 0; j < 3; j++) {
-             colors.push(...rainbowColors[i]);
-         }
-     }
- 
-     return colors;
- }
- 
  const vertexData = new Float32Array(triangles);
  const vertexBuffer = gl.createBuffer(gl.ARRAY_BUFFER);

  gl.enableVertexAttribArray(positionLocation);
  gl.vertexAttribPointer(positionLocation, attributeSize, type, nomralized, stride, offset);

- // gl.enableVertexAttribArray(colorLocation);
- // gl.vertexAttribPointer(colorLocation, 4, type, nomralized, stride, 8);
- 
  gl.drawElements(gl.TRIANGLES, indexData.length, gl.UNSIGNED_BYTE, 0);

Webpack will help us keep our codebase cleaner in the future, but we're good for now

See you tomorrow 👋


This is a series of blog posts related to WebGL. New post will be available every day

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Join mailing list to get new posts right to your inbox

Source code available here

Built with

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