twgl.js

TWGL: A Tiny WebGL helper Library

[rhymes with wiggle]

This library's sole purpose is to make using the WebGL API less verbose.

TL;DR

If you want to get stuff done use three.js. If you want to do stuff low-level with WebGL consider using TWGL.

The tiniest example

Not including the shaders (which is a simple quad shader) here's the entire code

<canvas id="c"></canvas>
<script src="../dist/4.x/twgl-full.min.js"></script>
<script>
  const gl = document.getElementById("c").getContext("webgl");
  const programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);

  const arrays = {
    position: [-1, -1, 0, 1, -1, 0, -1, 1, 0, -1, 1, 0, 1, -1, 0, 1, 1, 0],
  };
  const bufferInfo = twgl.createBufferInfoFromArrays(gl, arrays);

  function render(time) {
    twgl.resizeCanvasToDisplaySize(gl.canvas);
    gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

    const uniforms = {
      time: time * 0.001,
      resolution: [gl.canvas.width, gl.canvas.height],
    };

    gl.useProgram(programInfo.program);
    twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);
    twgl.setUniforms(programInfo, uniforms);
    twgl.drawBufferInfo(gl, bufferInfo);

    requestAnimationFrame(render);
  }
  requestAnimationFrame(render);
</script>

And here it is live.

Why? What? How?

WebGL is a very verbose API. Setting up shaders, buffers, attributes and uniforms takes a lot of code. A simple lit cube in WebGL might easily take over 60 calls into WebGL.

At its core there's really only a few main functions

• twgl.createProgramInfo compiles a shader and creates setters for attribs and uniforms
• twgl.createBufferInfoFromArrays creates buffers and attribute settings
• twgl.setBuffersAndAttributes binds buffers and sets attributes
• twgl.setUniforms sets the uniforms
• twgl.createTextures creates textures of various sorts
• twgl.createFramebufferInfo creates a framebuffer and attachments.

There's a few extra helpers and lower-level functions if you need them but those 6 functions are the core of TWGL.

Compare the TWGL vs WebGL code for a point lit cube.

Compiling a Shader and looking up locations

TWGL

const programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);

WebGL

// Note: I'm conceding that you'll likely already have the 30 lines of
// code for compiling GLSL
const program = twgl.createProgramFromScripts(gl, ["vs", "fs"]);

const u_lightWorldPosLoc = gl.getUniformLocation(program, "u_lightWorldPos");
const u_lightColorLoc = gl.getUniformLocation(program, "u_lightColor");
const u_ambientLoc = gl.getUniformLocation(program, "u_ambient");
const u_specularLoc = gl.getUniformLocation(program, "u_specular");
const u_shininessLoc = gl.getUniformLocation(program, "u_shininess");
const u_specularFactorLoc = gl.getUniformLocation(program, "u_specularFactor");
const u_diffuseLoc = gl.getUniformLocation(program, "u_diffuse");
const u_worldLoc = gl.getUniformLocation(program, "u_world");
const u_worldInverseTransposeLoc = gl.getUniformLocation(program, "u_worldInverseTranspose");
const u_worldViewProjectionLoc = gl.getUniformLocation(program, "u_worldViewProjection");
const u_viewInverseLoc = gl.getUniformLocation(program, "u_viewInverse");

const positionLoc = gl.getAttribLocation(program, "a_position");
const normalLoc = gl.getAttribLocation(program, "a_normal");
const texcoordLoc = gl.getAttribLocation(program, "a_texcoord");

Creating Buffers for a Cube

TWGL

const arrays = {
  position: [1,1,-1,1,1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,-1,-1,-1,-1,-1,-1,1,-1,1,1,1,1,1,1,1,-1,-1,1,-1,-1,-1,-1,1,-1,-1,1,-1,1,-1,-1,1,1,1,1,-1,1,1,-1,-1,1,1,-1,1,-1,1,-1,1,1,-1,1,-1,-1,-1,-1,-1],
  normal:   [1,0,0,1,0,0,1,0,0,1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,-1,0,0,-1,0,0,-1,0,0,-1],
  texcoord: [1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1],
  indices:  [0,1,2,0,2,3,4,5,6,4,6,7,8,9,10,8,10,11,12,13,14,12,14,15,16,17,18,16,18,19,20,21,22,20,22,23],
};
const bufferInfo = twgl.createBufferInfoFromArrays(gl, arrays);

WebGL

const positions = [1,1,-1,1,1,1,1,-1,1,1,-1,-1,-1,1,1,-1,1,-1,-1,-1,-1,-1,-1,1,-1,1,1,1,1,1,1,1,-1,-1,1,-1,-1,-1,-1,1,-1,-1,1,-1,1,-1,-1,1,1,1,1,-1,1,1,-1,-1,1,1,-1,1,-1,1,-1,1,1,-1,1,-1,-1,-1,-1,-1];
const normals   = [1,0,0,1,0,0,1,0,0,1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,-1,0,0,-1,0,0,-1,0,0,-1,0,0,0,1,0,0,1,0,0,1,0,0,1,0,0,-1,0,0,-1,0,0,-1,0,0,-1];
const texcoords = [1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1,1,0,0,0,0,1,1,1];
const indices   = [0,1,2,0,2,3,4,5,6,4,6,7,8,9,10,8,10,11,12,13,14,12,14,15,16,17,18,16,18,19,20,21,22,20,22,23];

const positionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);
const normalBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, normalBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(normals), gl.STATIC_DRAW);
const texcoordBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(texcoords), gl.STATIC_DRAW);
const indicesBuffer = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indicesBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(indices), gl.STATIC_DRAW);

Setting Attributes and Indices for a Cube

TWGL

twgl.setBuffersAndAttributes(gl, programInfo, bufferInfo);

WebGL

gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.vertexAttribPointer(positionLoc, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(positionLoc);
gl.bindBuffer(gl.ARRAY_BUFFER, normalBuffer);
gl.vertexAttribPointer(normalLoc, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(normalLoc);
gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
gl.vertexAttribPointer(texcoordLoc, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(texcoordLoc);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indicesBuffer);

Setting Uniforms for a Lit Cube

TWGL

// At Init time
const uniforms = {
  u_lightWorldPos: [1, 8, -10],
  u_lightColor: [1, 0.8, 0.8, 1],
  u_ambient: [0, 0, 0, 1],
  u_specular: [1, 1, 1, 1],
  u_shininess: 50,
  u_specularFactor: 1,
  u_diffuse: tex,
};

// At render time
uniforms.u_viewInverse = camera;
uniforms.u_world = world;
uniforms.u_worldInverseTranspose = m4.transpose(m4.inverse(world));
uniforms.u_worldViewProjection = m4.multiply(viewProjection, world);

twgl.setUniforms(programInfo, uniforms);

WebGL

// At Init time
const u_lightWorldPos = [1, 8, -10];
const u_lightColor = [1, 0.8, 0.8, 1];
const u_ambient = [0, 0, 0, 1];
const u_specular = [1, 1, 1, 1];
const u_shininess = 50;
const u_specularFactor = 1;
const u_diffuse = 0;

// At render time
gl.uniform3fv(u_lightWorldPosLoc, u_lightWorldPos);
gl.uniform4fv(u_lightColorLoc, u_lightColor);
gl.uniform4fv(u_ambientLoc, u_ambient);
gl.uniform4fv(u_specularLoc, u_specular);
gl.uniform1f(u_shininessLoc, u_shininess);
gl.uniform1f(u_specularFactorLoc, u_specularFactor);
gl.uniform1i(u_diffuseLoc, u_diffuse);
gl.uniformMatrix4fv(u_viewInverseLoc, false, camera);
gl.uniformMatrix4fv(u_worldLoc, false, world);
gl.uniformMatrix4fv(u_worldInverseTransposeLoc, false, m4.transpose(m4.inverse(world)));
gl.uniformMatrix4fv(u_worldViewProjectionLoc, false, m4.multiply(viewProjection, world));

Loading / Setting up textures

TWGL

const textures = twgl.createTextures(gl, {
  // a power of 2 image
  hftIcon: { src: "images/hft-icon-16.png", mag: gl.NEAREST },
  // a non-power of 2 image
  clover: { src: "images/clover.jpg" },
  // From a canvas
  fromCanvas: { src: ctx.canvas },
  // A cubemap from 6 images
  yokohama: {
    target: gl.TEXTURE_CUBE_MAP,
    src: [
      'images/yokohama/posx.jpg',
      'images/yokohama/negx.jpg',
      'images/yokohama/posy.jpg',
      'images/yokohama/negy.jpg',
      'images/yokohama/posz.jpg',
      'images/yokohama/negz.jpg',
    ],
  },
  // A cubemap from 1 image (can be 1x6, 2x3, 3x2, 6x1)
  goldengate: {
    target: gl.TEXTURE_CUBE_MAP,
    src: 'images/goldengate.jpg',
  },
  // A 2x2 pixel texture from a JavaScript array
  checker: {
    mag: gl.NEAREST,
    min: gl.LINEAR,
    src: [
      255,255,255,255,
      192,192,192,255,
      192,192,192,255,
      255,255,255,255,
    ],
  },
  // a 1x8 pixel texture from a typed array.
  stripe: {
    mag: gl.NEAREST,
    min: gl.LINEAR,
    format: gl.LUMINANCE,
    src: new Uint8Array([
      255,
      128,
      255,
      128,
      255,
      128,
      255,
      128,
    ]),
    width: 1,
  },
});

WebGL

// Let's assume I already loaded all the images

// a power of 2 image
const hftIconTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, hftIconImg);
gl.generateMipmaps(gl.TEXTURE_2D);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
// a non-power of 2 image
const cloverTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, hftIconImg);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
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);
// From a canvas
const cloverTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, ctx.canvas);
gl.generateMipmaps(gl.TEXTURE_2D);
// A cubemap from 6 images
const yokohamaTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_CUBE_MAP, tex);
gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_X, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, posXImg);
gl.texImage2D(gl.TEXTURE_CUBE_MAP_NEGATIVE_X, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, negXImg);
gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_Y, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, posYImg);
gl.texImage2D(gl.TEXTURE_CUBE_MAP_NEGATIVE_Y, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, negYImg);
gl.texImage2D(gl.TEXTURE_CUBE_MAP_POSITIVE_Z, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, posZImg);
gl.texImage2D(gl.TEXTURE_CUBE_MAP_NEGATIVE_Z, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, negZImg);
gl.generateMipmaps(gl.TEXTURE_CUBE_MAP);
// A cubemap from 1 image (can be 1x6, 2x3, 3x2, 6x1)
const goldengateTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_CUBE_MAP, tex);
const size = goldengate.width / 3;  // assume it's a 3x2 texture
const slices = [0, 0, 1, 0, 2, 0, 0, 1, 1, 1, 2, 1];
const tempCtx = document.createElement("canvas").getContext("2d");
tempCtx.canvas.width = size;
tempCtx.canvas.height = size;
for (let ii = 0; ii < 6; ++ii) {
  const xOffset = slices[ii * 2 + 0] * size;
  const yOffset = slices[ii * 2 + 1] * size;
  tempCtx.drawImage(element, xOffset, yOffset, size, size, 0, 0, size, size);
  gl.texImage2D(faces[ii], 0, format, format, type, tempCtx.canvas);
}
gl.generateMipmaps(gl.TEXTURE_CUBE_MAP);
// A 2x2 pixel texture from a JavaScript array
const checkerTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 2, 2, 0, gl.RGBA, gl.UNSIGNED_BYTE, new Uint8Array([
    255,255,255,255,
    192,192,192,255,
    192,192,192,255,
    255,255,255,255,
  ]));
gl.generateMipmaps(gl.TEXTURE_2D);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
// a 1x8 pixel texture from a typed array.
const stripeTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.LUMINANCE, 1, 8, 0, gl.LUMINANCE, gl.UNSIGNED_BYTE, new Uint8Array([
    255,
    128,
    255,
    128,
    255,
    128,
    255,
    128,
  ]));
gl.generateMipmaps(gl.TEXTURE_2D);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);

Creating Framebuffers and attachments

TWGL

const attachments = [
  { format: RGBA, type: UNSIGNED_BYTE, min: LINEAR, wrap: CLAMP_TO_EDGE },
  { format: DEPTH_STENCIL, },
];
const fbi = twgl.createFramebufferInfo(gl, attachments);

WebGL

const fb = gl.createFramebuffer(gl.FRAMEBUFFER);
gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
const tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.drawingBufferWidth, gl.drawingBufferHeight, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
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.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);
const rb = gl.createRenderbuffer();
gl.bindRenderbuffer(gl.RENDERBUFFER, rb);
gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_STENCIL, gl.drawingBufferWidth, gl.drawingBufferHeight);
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, rb);

Compare

TWGL example vs WebGL example

Examples

• tiny
• twgl cube
• textures
• primitives
• 2d-lines
• dynamic-buffers
• zoom-around
• text
• kaleidoscope
• tunnel
• GPGPU particles
• item list
• no box skybox
• cross origin
• vertex array objects
• instancing

WebGL 2 Examples

• uniform buffer objects
• 3d textures tone mapping
• samplers
• webgl2 textures
• 3d texture volume
• 3d texture volume no buffers
• 2d array texture
• transform feedback

OffscreenCanvas Example

• OffscreenCanvas

ES6 module support

• modules

AMD support

• amd

CommonJS / Browserify support

• browserify

Other Features

• Includes some optional 3d math functions (full version)

  You are welcome to use any math library as long as it stores matrices as flat Float32Array or JavaScript arrays.

• Includes some optional primitive generators (full version)

  planes, cubes, spheres, ... Just to help get started

Usage

See the examples. Otherwise there's a few different versions

• twgl-full.module.js the es6 module version
• twgl-full.min.js the minified full version
• twgl-full.js the concatenated full version
• twgl.min.js the minimum version (no 3d math, no primitives)
• twgl.js the concatenated minimum version (no 3d math, no primitives)

Download

• from github

  http://github.com/greggman/twgl.js

• from bower

  bower install twgl.js
  

• from npm

  npm install twgl.js
  

  or

  npm install twgl-base.js
  

• from git

  git clone https://github.com/greggman/twgl.js.git
  

Rationale and other chit-chat

TWGL's is an attempt to make WebGL simpler by providing a few tiny helper functions that make it much less verbose and remove the tedium. TWGL is NOT trying to help with the complexity of managing shaders and writing GLSL. Nor is it a 3D library like three.js. It's just trying to make WebGL less verbose.

TWGL can be considered a spiritual successor to TDL. Where as TDL created several classes that wrapped WebGL, TWGL tries not to wrap anything. In fact you can manually create nearly all TWGL data structures.

For example the function setAttributes takes an object of attributes. In WebGL you might write code like this

gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.vertexAttribPointer(positionLoc, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(positionLoc);
gl.bindBuffer(gl.ARRAY_BUFFER, normalBuffer);
gl.vertexAttribPointer(normalLoc, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(normalLoc);
gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
gl.vertexAttribPointer(texcoordLoc, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(texcoordLoc);
gl.bindBuffer(gl.ARRAY_BUFFER, colorsBuffer);
gl.vertexAttribPointer(colorLoc, 4, gl.UNSIGNED_BYTE, true, 0, 0);
gl.enableVertexAttribArray(colorLoc);

setAttributes is just the simplest code to do that for you.

// make attributes for TWGL manually
const attribs = {
  a_position: { buffer: positionBuffer, size: 3, },
  a_normal:   { buffer: normalBuffer,   size: 3, },
  a_texcoord: { buffer: texcoordBuffer, size: 2, },
  a_color:    { buffer: colorBuffer,    size: 4, type: gl.UNSIGNED_BYTE, normalize: true, },
};
twgl.setAttributes(attribSetters, attribs);

The point of the example above is TWGL is a thin wrapper. All it's doing is trying to make common WebGL operations easier and less verbose. Feel free to mix it with raw WebGL.

API Docs

API Docs are here.

Want to learn WebGL?

Try webglfundamentals.org