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

compiles a shader and creates setters for attribs and uniforms twgl.createBufferInfoFromArrays creates buffers and attribute settings

creates buffers and attribute settings twgl.setBuffersAndAttributes binds buffers and sets attributes

binds buffers and sets attributes twgl.setUniforms sets the uniforms

sets the uniforms twgl.createTextures creates textures of various sorts

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, 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, 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

WebGL 2 Examples

OffscreenCanvas Example

ES6 module support

AMD support

CommonJS / Browserify 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.module.js the es6 module version

the es6 module version twgl-full.min.js the minified full version

the minified full version twgl-full.js the concatenated full version

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

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