What is regl?
regl is a functional abstraction for WebGL that simplifies the process of creating and managing WebGL contexts and rendering pipelines. It provides a declarative API for defining shaders, buffers, and other WebGL resources, making it easier to build complex graphics applications.
What are regl's main functionalities?
Creating a WebGL Context
This code initializes a new regl instance, which sets up a WebGL context and prepares it for rendering.
const regl = require('regl')();
Drawing a Simple Triangle
This code defines a simple triangle using regl. It specifies the vertex and fragment shaders, the vertex positions, and the draw call. The triangle is drawn in each frame.
const drawTriangle = regl({
frag: `
precision mediump float;
void main () {
gl_FragColor = vec4(1, 0, 0, 1);
}
`,
vert: `
precision mediump float;
attribute vec2 position;
void main () {
gl_Position = vec4(position, 0, 1);
}
`,
attributes: {
position: [
[-1, 0],
[0, -1],
[1, 1]
]
},
count: 3
});
regl.frame(() => {
regl.clear({
color: [0, 0, 0, 1],
depth: 1
});
drawTriangle();
});
Managing Buffers
This code demonstrates how to create and use a buffer in regl. The buffer stores vertex positions, which are then used in the draw call.
const positionBuffer = regl.buffer([
[-1, 0],
[0, -1],
[1, 1]
]);
const drawWithBuffer = regl({
frag: `
precision mediump float;
void main () {
gl_FragColor = vec4(0, 1, 0, 1);
}
`,
vert: `
precision mediump float;
attribute vec2 position;
void main () {
gl_Position = vec4(position, 0, 1);
}
`,
attributes: {
position: positionBuffer
},
count: 3
});
regl.frame(() => {
regl.clear({
color: [0, 0, 0, 1],
depth: 1
});
drawWithBuffer();
});
Using Uniforms
This code shows how to use uniforms in regl. The uniform 'color' is passed to the fragment shader, allowing dynamic control over the color of the rendered triangle.
const drawWithUniforms = regl({
frag: `
precision mediump float;
uniform vec4 color;
void main () {
gl_FragColor = color;
}
`,
vert: `
precision mediump float;
attribute vec2 position;
void main () {
gl_Position = vec4(position, 0, 1);
}
`,
attributes: {
position: [
[-1, 0],
[0, -1],
[1, 1]
]
},
uniforms: {
color: [0, 0, 1, 1]
},
count: 3
});
regl.frame(() => {
regl.clear({
color: [0, 0, 0, 1],
depth: 1
});
drawWithUniforms();
});
Other packages similar to regl
three
Three.js is a popular JavaScript library for creating 3D graphics in the browser. It provides a higher-level abstraction compared to regl, making it easier to create complex 3D scenes with less code. However, it may not offer the same level of control and performance optimization as regl.
pixi
PixiJS is a 2D rendering engine that uses WebGL for high-performance graphics. It is designed for creating interactive graphics and games, offering a simpler API compared to regl. While it is more focused on 2D graphics, it can also handle some 3D rendering tasks.
babylonjs
Babylon.js is a powerful, open-source 3D engine that provides a comprehensive set of features for creating 3D applications. It offers a higher-level API than regl, making it easier to get started with 3D graphics, but it may not provide the same fine-grained control over WebGL resources.
👑
regl
Fast functional WebGL
Example
regl
simplifies WebGL programming by removing as much shared state as it can get away with. To do this, it replaces the WebGL API with two fundamental abstractions, resources and commands:
- A resource is a handle to a GPU resident object, like a texture, FBO or buffer.
- A command is a complete representation of the WebGL state required to perform some draw call.
To define a command you specify a mixture of static and dynamic data for the object. Once this is done, regl
takes this description and then compiles it into optimized JavaScript code. For example, here is a simple regl
program to draw a triangle:
const regl = require('regl')()
const drawTriangle = regl({
frag: `
precision mediump float;
uniform vec4 color;
void main() {
gl_FragColor = color;
}`,
vert: `
precision mediump float;
attribute vec2 position;
void main() {
gl_Position = vec4(position, 0, 1);
}`,
attributes: {
position: regl.buffer([
[-2, -2],
[4, -2],
[4, 4]
])
},
uniforms: {
color: regl.prop('color')
},
count: 3
})
regl.frame(({time}) => {
regl.clear({
color: [0, 0, 0, 0],
depth: 1
})
drawTriangle({
color: [
Math.cos(time * 0.001),
Math.sin(time * 0.0008),
Math.cos(time * 0.003),
1
]
})
})
See this example live
Check out the gallery. The source code of all the gallery examples can be found here.
Setup
regl
has no dependencies, so setting it up is pretty easy. There are 3 basic ways to do this:
Live editing
To try out regl right away, you can use the live editor in the gallery.
npm
The easiest way to use regl
in a project is via npm. Once you have node set up, you can install and use regl
in your project using the following command:
npm i -S regl
For more info on how to use npm, check out the official docs.
If you are using npm, you may also want to try budo
which is a live development server.
Run time error checking and browserify
By default if you compile regl
with browserify
then all error messages and run time checks are removed. This is done to reduce the size of the final bundle. If you are developing an application, you should run browserify using the --debug
flag in order to enable error messages. This will also generate source maps which make reading the source code of your application easier.
Standalone script tag
You can also use regl
as a standalone script if you are really stubborn. The most recent versions can be found in the dist/
folder and is also available from npm cdn in both minified and unminified versions.
There are some difference when using regl
in standalone. Because script tags don't assume any sort of module system, the standalone scripts inject a global constructor function which is equivalent to the module.exports
of regl
:
<!DOCTYPE html>
<html>
<head>
<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport" />
<meta charset=utf-8>
</head>
<body>
</body>
<script language="javascript" src="https://npmcdn.com/regl/dist/regl.js"></script>
<script language="javascript">
var regl = createREGL()
regl.frame(function () {
regl.clear({
color: [0, 0, 0, 1]
})
})
</script>
</html>
Why regl
regl
just removes shared state from WebGL. You can do anything you could in regular WebGL with little overhead and way less debugging. regl
emphasizes the following values:
- Simplicity The interface is concise and emphasizes separation of concerns. Removing shared state helps localize the effects and interactions of code, making it easier to reason about.
- Correctness
regl
has more than 30,000 unit tests and above 95% code coverage. In development mode, regl
performs strong validation and sanity checks on all input data to help you catch errors faster. - Performance
regl
uses dynamic code generation and partial evaluation to remove almost all overhead. - Minimalism
regl
just wraps WebGL. It is not a game engine and doesn't have opinions about scene graphs or vector math libraries. Any feature in WebGL is accessible, including advanced extensions like multiple render targets or instancing. - Stability
regl
takes interface compatibility and semantic versioning seriously, making it well suited for long lived applications that must be supported for months or years down the road. It also has no dependencies limiting exposure to risky or unplanned updates.
While regl
is lower level than many 3D engines, code written in it tends to be highly compact and flexible. A comparison of regl
to various other WebGL libraries across several tasks can be found here.
In order to prevent performance regressions, regl
is continuously
benchmarked. You can run benchmarks locally using npm run bench
or
check them out
online. The
results for the last few days can be found
here.
These measurements were taken using our custom scripts bench-history
and
bench-graph
. You can read more about them in the development guide.
Projects using regl
The following is an incomplete list of projects using regl:
If you have a project using regl that isn't on this list that you would like to see added, please send us a pull request!
regl is still under active developement, and anyone willing to contribute is very much welcome to do so. Right now, what we need the most is for people to write examples and demos with the framework. This will allow us to find bugs and deficiencies in the API. We have a list of examples we would like to be implemented here, but you are of course welcome to come up with your own examples. To add an example to our gallery of examples, please send us a pull request!
regl
has extensive API documentation. You can browse the docs online here.
The latest changes in regl
can be found in the CHANGELOG.
For info on how to build and test headless, see the contributing guide here
All code (c) 2016 MIT License
Development supported by the Freeman Lab and the Howard Hughes Medical Institute (@freeman-lab on GitHub)
Asset licenses
Many examples use creative commons or public domain artwork for illustrative purposes. These assets are not included in any of the redistributable packages of regl.
- Peppers test image for cube comparison is public domain
- Test video (doggie-chromakey.ogv) by L0ckergn0me, used under creative commons license
- Cube maps (posx.jpeg, negx.jpeg, posy.jpeg, negy.jpeg, posz.jpeg, negz.jpeg) by Humus, used under creative commons 3 license
- Environment map of Oregon (ogd-oregon-360.jpg) due to Max Ogden (@maxogd on GitHub)
- DDS test images (alpine_cliff_a, alpine_cliff_a_norm, alpine_cliff_a_spec) taken from the CC0 license 0-AD texture pack by Wildfire games
- Tile set for tile mapping demo (tiles.png) from CC0 licensed cobblestone paths pack
- Audio track for
audio.js
example is "Bamboo Cactus" by 8bitpeoples. CC BY-ND-NC 1.0 license - Matcap (spheretexture.jpg) by Ben Simonds. CC 3 license.
- Normal map (normaltexture.jpg) by rubberduck. CC0 license.