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GitHub - zachwinter/fragment-shader: A lightweight, performant WebGL fragment sh...

 1 year ago
source link: https://github.com/zachwinter/fragment-shader
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fragment-shader

This project owns two primary features: a minimalist shader renderer and a live code editor (try it here!).

• /classes/Shader.ts – A lightweight & highly performant WebGL fragment shader renderer written in TypeScript.

  • Appx. 3kb (gzipped).
  • Phenomal performance characteristics, both in rendering speed and in memory consumption.
  • Extremely minimal taxing of the garbage collector.
  • Certified jank-free – if your experience differs, please let me know!
  • Zero-configuration instantiation (see Shader.ts section for details on all default behaviors).

• /classes/Editor.ts – A live, in-browser GLSL code editor implemented with Codemirror, synced with an instance of Shader.ts.

  • Appx. 165kb (gzipped).
  • Live rendering! Shader re-renders on every keystroke.
  • Smart syntax highlighting and bracket matching.
  • Realtime autocomplete surfaces GLSL keywords, uniform names & more as you write your shader.
  • Shader compilation errors surface in the editor on relevant lines.
  • ShaderToy support! Paste your favorite shaders into the editor (work in progress).

Installation ( NPM )

npm install --save fragment-shader

To begin let's look at the core renderer, found in /classes/Shader.ts.

Shader.ts

Note there are several plugins in modern IDEs (VSCode, etc.) that enable GLSL syntax highlighting within template literals by prefacing them with /*glsl*/ – doesn't seem to work on GitHub though.

Bare Bones Implementation

import { Shader } from 'fragment-shader';

const glsl = /*glsl*/ `
  void main () {
    gl_FragColor = vec4(.8, .2, .7, 1.);
  }
`;

const shader = new Shader(glsl);

The above code example instantiates an instance of the Shader class and passes it but a single paramter: a string containing your fragment shader code. By default, the Shader class will instantiate a <canvas> element and append it directly to the <body>. The <canvas> will then be sized to match the size of the browser window (and the display's pixel density). Given the default configuration value of fillViewport being true, An event listener is then created for the resize event on the browser window, allowing the renderer and its <canvas> to resize according to the browser window changing size or orientation. Then, after bootstrapping a webgl2 rendering context, it prepares all internals (including compiling your shader) before finally initializing an internal requestAnimationFrame loop, syncing the rendering animation to the native refresh rate of the display. There are two methods on the shader instance for controlling rendering playback:

// Cancel the `requestAnimationFrame` loop.
shader.stop();

// Resume the `requestAnimationFrame` loop.
shader.start();

Configured Implementation

If you wish for the renderer to behave differently than its default configuration, you can do so by passing the constructor a configuration object. The object's shape (and its default values) look like this:

import { Shader, type ShaderConfig } from 'fragment-shader';

const config: ShaderConfig = {
  shader: /*glsl*/ `
    void main () {
      gl_FragColor = vec4(.8, .2, .7, 1.);
    }
  `,
  target: document.body,
  uniforms: [],
  width: window.innerWidth,
  height: window.innerHeight,
  dpr: window.devicePixelRatio,
  fillViewport: true,
  onSuccess: () => {},
  onError: () => {},
  animate: true,
  debug: false,
};

const shader = new Shader(config);

Note If you explicitly set width or height, the renderer sets fillViewport to false.

If you become accustomed to the shader being the first argument of the constructor, you can instantiate this way:

import { Shader, type ShaderConfig } from 'fragment-shader';

const config: ShaderConfig = { ... }

const shader = new Shader(/*glsl*/ `
  void main () {
    gl_FragColor = vec4(.8, .2, .7, 1.);
  }
`, config);

Note If you set animate to false, the shader will render its initial frame, but from thereon out you will be responsible for calling the tick() method on the Shader if you wish to update it – for example, within a requestAnimationFrame loop:

import { Shader, type ShaderConfig } from 'fragment-shader';

const config: ShaderConfig = {
  shader: /*glsl*/ `
    void main () {
      gl_FragColor = vec4(.8, .2, .7, 1.);
    }
  `,
  animate: false,
};

const shader = new Shader(config);

const tick = (now: DOMHighResTimeStamp) => {
  requestAnimationFrame(tick);
  shader.tick(now);
};

requestAnimationFrame(tick);

Uniforms

We can pass any number of Uniform values to our shaders. Uniforms passed to the Shader class are automatically injected into our shaders without having to define them explicitly. The renderer expects an array of uniforms, each of type UniformValue. The first index ([0]) of a UniformValue defines its name, the second ([1]) defines its type, and the third ([2]) defines its value.

Note Please note that uniforms of type bool are unique in that their values aren't contained within an array.

import { Shader, type UniformValue } from 'fragment-shader';

const zoom: UniformValue = ['zoom', 0, [2.5]];
const color: UniformValue = ['color', 3, [0.8, 0.2, 0.6]];
const warp: UniformValue = ['warp', 1, false];

const shader = new Shader({
  shader: /*glsl*/ `
    void main () {
      gl_FragColor = vec4(color, 1.);
    }
  `,
  uniforms: [zoom, color, warp],
});

Types are mapped as follows:

const SHADER_TYPE_MAP = {
  0: 'float',
  1: 'bool',
  2: 'vec2',
  3: 'vec3',
  4: 'vec4',
};

Updating / Cleanup

// Update a uniform value.
shader.setUniform('color', [0.1, 0.6, 0.9]);

// Rebuild with a new shader.
shader.rebuild({ shader, uniforms });

// Destroy shader instance, elements, and event handlers.
shader.destroy();

Editor.ts

Instantiating an Editor should feel familiar after working with the Shader class:

import { Editor, type EditorConfig } from 'fragment-shader';

const config: EditorConfig = {
  shader: /*glsl*/ `
    void main () {
      gl_FragColor = vec4(.8, .2, .7, 1.);
    }
  `,
  uniforms: []
  target: document.body,
  width: window.innerWidth,
  height: window.innerHeight,
  dpr: window.devicePixelRatio,
  fillViewport: true,
  showLineNumbers: true,
  showErrors: true,
  onError: () => {},
  onSuccess: () => {},
  onUpdate: () => {},
};

const editor = new Editor(config);

An Editor shares several Shader methods:

// Cancel the `requestAnimationFrame` loop.
editor.stop();

// Resume the `requestAnimationFrame` loop.
editor.start();

// Update a uniform value.
editor.setUniform('warp', false);

// Rebuild with a new shader.
editor.rebuild({ shader, uniforms });

// Destroy instance.
editor.destroy();

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