5l1v3r1 / ogl

Minimal WebGL Library

OGL

Minimal WebGL library.

⚠️ Note: currently in alpha, so expect breaking changes.

See the Examples!

OGL is a small, effective WebGL library aimed at developers who like minimal layers of abstraction, and are comfortable creating their own shaders.

Written in es6 modules with zero dependencies, the API shares many similarities with ThreeJS, however it is tightly coupled with WebGL and comes with much fewer features.

In its design, the library does the minimum abstraction necessary, so devs should still feel comfortable using it in conjunction with native WebGL commands.

Keeping the level of abstraction low helps to make the library easier to understand, extend, and also makes it more practical as a WebGL learning resource.

Install

Download and load directly in the browser using es6 modules - no dev-stack required.

or

npm i ogl

Examples

Show me what you got! - Explore a comprehensive list of examples, with comments in the source code.

Inspired by the effectiveness of ThreeJS' examples, they will hopefully serve as reference for how to use the library, and to achieve a wide range of techniques.

Weight

Even though the source is modular, as a guide, below are the complete component download sizes.

Component	Size (minzipped)
Core	8kb
Math	6kb
Extras	10kb
Total	24kb

With tree-shaking applied in a build step, one can expect the final size to be much lighter than the values above.

Usage

If installed amongst your project files, importing can be done from one single entry point.

import { ... } from './path/to/src/index.mjs';

Else if using a bundler with node modules, then import directly from the installed node module.

import { ... } from 'ogl';

By default, the ES source modules are loaded (src/index.mjs). If your bundler doesn't support ES modules (eg Browserify, Vue SSR), the simplest solution is to just target the UMD bundle instead.

import { ... } from 'ogl/dist/ogl.umd.js';

As another alternative, you could load from a CDN, using either the jsdelivr or unpkg services.

import {...} from 'https://cdn.jsdelivr.net/npm/ogl';
import {...} from 'https://unpkg.com/ogl';

If you take this route, I would highly recommend defining a specific version (append @x.x.x) to avoid code breaking, rather than fetching the latest version, as per the above links.

As a basic API example, below renders a spinning white cube.

{
    import {Renderer, Camera, Transform, Box, Program, Mesh } from 'ogl';

    const renderer = new Renderer();
    const gl = renderer.gl;
    document.body.appendChild(gl.canvas);

    const camera = new Camera(gl);
    camera.position.z = 5;

    function resize() {
        renderer.setSize(window.innerWidth, window.innerHeight);
        camera.perspective({
            aspect: gl.canvas.width / gl.canvas.height,
        });
    }
    window.addEventListener('resize', resize, false);
    resize();

    const scene = new Transform();

    const geometry = new Box(gl);

    const program = new Program(gl, {
        vertex: `
            attribute vec3 position;

            uniform mat4 modelViewMatrix;
            uniform mat4 projectionMatrix;

            void main() {
                gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
            }
            `,
        fragment: `
            void main() {
                gl_FragColor = vec4(1.0);
            }
        `,
    });

    const mesh = new Mesh(gl, {geometry, program});
    mesh.setParent(scene);

    requestAnimationFrame(update);
    function update(t) {
        requestAnimationFrame(update);

        mesh.rotation.y -= 0.04;
        mesh.rotation.x += 0.03;
        renderer.render({scene, camera});
    }
}

Here you can play with the above template live in a codesandbox https://codesandbox.io/s/ogl-5i69p

For a simpler use, such as a full-screen shader, more of the core can be omitted as a scene graph (Transform) and projection matrices (Camera) are not necessary. We'll also show how to easily create custom geometry.

import {Renderer, Geometry, Program, Mesh} from 'ogl';

{
    const renderer = new Renderer({
        width: window.innerWidth,
        height: window.innerHeight,
    });
    const gl = renderer.gl;
    document.body.appendChild(gl.canvas);

    // Triangle that covers viewport, with UVs that still span 0 > 1 across viewport
    const geometry = new Geometry(gl, {
        position: {size: 2, data: new Float32Array([-1, -1, 3, -1, -1, 3])},
        uv: {size: 2, data: new Float32Array([0, 0, 2, 0, 0, 2])},
    });
    // Alternatively, you could use the Triangle class.

    const program = new Program(gl, {
        vertex: `
            attribute vec2 uv;
            attribute vec2 position;

            varying vec2 vUv;

            void main() {
                vUv = uv;
                gl_Position = vec4(position, 0, 1);
            }
        `,
        fragment: `
            precision highp float;

            uniform float uTime;

            varying vec2 vUv;

            void main() {
                gl_FragColor.rgb = vec3(0.8, 0.7, 1.0) + 0.3 * cos(vUv.xyx + uTime);
                gl_FragColor.a = 1.0;
            }
        `,
        uniforms: {
            uTime: {value: 0},
        },
    });

    const mesh = new Mesh(gl, {geometry, program});

    requestAnimationFrame(update);
    function update(t) {
        requestAnimationFrame(update);

        program.uniforms.uTime.value = t * 0.001;

        // Don't need a camera if camera uniforms aren't required
        renderer.render({scene: mesh});
    }
}

Structure

In an attempt to keep things light and modular, the library is split up into three components: Math, Core, and Extras.

The Math component is an extension of gl-matrix, providing instancable classes that extend Array for each of the module types. 7kb when gzipped, it has no dependencies and can be used separately.

The Core is made up of the following:

• Geometry.js
• Program.js
• Renderer.js
• Camera.js
• Transform.js
• Mesh.js
• Texture.js
• RenderTarget.js

Any additional layers of abstraction will be included as Extras, and not part of the core as to reduce bloat.

Below is an Extras wish-list, and is still a work-in-progress as examples are developed.

• Plane.js
• Box.js
• Sphere.js
• Cylinder.js
• Triangle.js
• Orbit.js
• Raycast.js
• Curve.js
• Post.js
• Skin.js
• Animation.js
• Text.js
• NormalProgram.js
• Flowmap.js
• GPGPU.js
• Polyline.js
• Shadow.js
• KTXTexture.js
• TextureLoader.js
• GLTFLoader.js
• OBJLoader.js