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 shit 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/twgl-full.min.js"></script>
<script>
  var gl = twgl.getWebGLContext(document.getElementById("c"));
  var programInfo = twgl.createProgramInfo(gl, ["vs", "fs"]);

  var arrays = {
    position: [-1, -1, 0, 1, -1, 0, -1, 1, 0, -1, 1, 0, 1, -1, 0, 1, 1, 0],
  };
  var bufferInfo = twgl.createBufferInfoFromArrays(gl, arrays);
  var start = Date.now() * 0.001;

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

    var uniforms = {
      time: Date.now() * 0.001 - start,
      resolution: [gl.canvas.width, gl.canvas.height],
    };

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

    requestAnimationFrame(render);
  }
  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

There's a few extra helpers and lower-level functions if you need them but those 5 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

var 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
var program = twgl.createProgramFromScripts(gl, ["vs", "fs"]);

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

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

Creating Buffers for a Cube

TWGL

var 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],
};
var bufferInfo = twgl.createBufferInfoFromArrays(gl, arrays);

WebGL

var 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];
var 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];
var 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];
var 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];

var positionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, positionBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(positions), gl.STATIC_DRAW);
var normalBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, normalBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(normals), gl.STATIC_DRAW);
var texcoordBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, texcoordBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(texcoords), gl.STATIC_DRAW);
var 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
var 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(world, viewProjection);

twgl.setUniforms(programInfo, uniforms);

WebGL

// At Init time
var u_lightWorldPos = [1, 8, -10];
var u_lightColor = [1, 0.8, 0.8, 1];
var u_ambient = [0, 0, 0, 1];
var u_specular = [1, 1, 1, 1];
var u_shininess = 50;
var u_specularFactor = 1;
var 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(world, viewProjection));

Loading / Setting up textures

TWGL

var 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
var 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
var 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
var 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
var 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)
var goldengateTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_CUBE_MAP, tex);
var size = goldengate.width / 3;  // assume it's a 3x2 texture
var slices = [0, 0, 1, 0, 2, 0, 0, 1, 1, 1, 2, 1];
var tempCtx = document.createElement("canvas").getContext("2d");
tempCtx.canvas.width = size;
tempCtx.canvas.height = size;
for (var ii = 0; ii < 6; ++ii) {
  var xOffset = slices[ii * 2 + 0] * size;
  var 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
var checkerTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 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.
var stripeTex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.LUMINANCE, 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);

Compare

TWGL example vs WebGL example

Examples

AMD support

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.min.js the minified full version
twgl-full.js the concatinated full version
twgl.min.js the minimum version (no 3d math, no primitives)
twgl.js the concatinated minimum version (no 3d math, no primitives)

API Docs

API Docs are here.

Download

from github

http://github.com/greggman/twgl.js
from bower
```
bower install twgl.js
```

from git

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

Rational 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
var 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, },
};
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.

Want to learn WebGL?

Try webglfundamentals.org

Future

What needs to change for WebGL 2.0?
Consider adding framebuffer related stuff

License

the1sky/twgl.js

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