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# 💎 glsl-canvas
[glsl-canvas-js](https://github.com/actarian/glsl-canvas) is a typescript porting of GlslCanvas, a javascript library that helps you easily load GLSL Fragment and Vertex Shaders into an HTMLCanvasElement. Originally made by [Patricio Gonzalez Vivo](http://patriciogonzalezvivo.com) author of [Book of Shaders](http://thebookofshaders.com) and [GlslEditor](http://editor.thebookofshaders.com).
***Now supporting WebGL2. just add `#version 300 es` at the very start of the file.***
---
> [Examples](https://actarian.github.io/glsl-canvas/)
> [Docs](https://actarian.github.io/glsl-canvas/api/)
___
## How to use
### With link
Load the latest version of ```glsl-canvas.js``` on your page by adding this line to your HTML:
```html
<script type="text/javascript" src="https://unpkg.com/glsl-canvas-js/dist/umd/glsl-canvas.min.js"></script>
```
### With npm
If you are using npm package manager type this command on your terminal:
```bash
npm install glsl-canvas-js --save
```
### Run with html
Add a canvas element on your page with class name ```glsl-canvas``` and assign a shader through a url using the ```data-fragment-url``` attribute.
Or write your shader directly in code using the ```data-fragment``` attribute.
```html
<canvas class="glsl-canvas" data-fragment-url="fragment.glsl" width="500" height="500"></canvas>
```
`GlslCanvas` will automatically load a WebGL context in that ```<canvas>``` element, compile the shader and animate it for you.
### Run with javascript
Create a ```<canvas>``` element and attach a new instance of ```glsl.Canvas```.
```javascript
const canvas = document.createElement('canvas');
const options = {
vertexString: `...`,
fragmentString: `...`,
alpha: false,
antialias: true,
mode: 'flat',
extensions: ['EXT_shader_texture_lod']
};
const glsl = new glsl.Canvas(canvas, options);
```
All the ```.glsl-canvas``` instances will be stored in the ```glsl.Canvas.items``` array.
### Import es6 module
```javascript
import { Canvas } from 'glsl-canvas-js';
const canvas = document.createElement('canvas');
const options = {
vertexString: `...`,
fragmentString: `...`,
alpha: false,
antialias: true,
mode: 'flat',
extensions: ['EXT_shader_texture_lod']
};
const glsl = new Canvas(canvas, options);
```
### Init options
GlslCanvas options inherit from [WebGLContextAttributes](https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/getContextAttributes). Here the complete list.
```js
const glsl = new Canvas(canvas, {
vertexString: '...',
fragmentString: '...',
backgroundColor: 'rgba(0.0, 0.0, 0.0, 0.0)',
alpha: true,
antialias: true,
depth: true,
desynchronized: false,
failIfMajorPerformanceCaveat: false,
powerPreference: 'default',
premultipliedAlpha: false,
preserveDrawingBuffer: false,
stencil: false,
doubleSided: false,
extensions: ['EXT_shader_texture_lod'],
workpath: 'rootfolder',
mode: 'mesh',
mesh: 'myfolder/myfile.obj',
onError: (error) => {}
});
```
___
### Default Shader Attributes
These attributes are automatically loaded for you.
| name | |
|----------------|-|
| `a_position` | a ```vec4``` with vertex position. |
| `a_normal` | a ```vec4``` with normal values. |
| `a_texture` | a ```vec2``` with texture coords mapping. |
| `a_color` | a ```vec4``` with face color info. |
___
### Default Uniforms
These uniforms are automatically loaded for you.
| name | |
|----------------|-|
| `u_time` | a ```float``` representing elapsed time in seconds. |
| `u_resolution` | a ```vec2``` representing the dimensions of the viewport. |
| `u_mouse` | a ```vec2``` representing the position of the mouse, defined in Javascript with ```.setMouse({x:[value],y:[value])```. |
| `u_texture_N` | a ```sampler2D``` containing textures loaded with the ```data-textures``` attribute. |
___
### Attributes
| name | |
|----------------------|-|
| `data-fragment` | load a fragment shader by providing the content of the shader as a string |
| `data-vertex` | load a vertex shader by providing the content of the shader as a string |
| `data-fragment-url` | load a fragment shader by providing a valid url |
| `data-vertex-url` | load a vertex shader by providing a valid url |
| `data-mode` | setup one of those modes ```flat```, ```box```, ```sphere```, ```torus```, ```mesh``` |
| `data-textures` | load a list of texture urls separated by commas (ex: ```data-textures="color.jpg,normal.png,bump.jpg"```). Textures will be assigned in order to ```uniform sampler2D``` variables with names following this style: ```u_texture_0```, ```u_texture_1```, ```u_texture_2```, etc. |
| `controls` | enable play on over functionality |
| `data-autoplay` | enable autoplay with controls feature |
___
### Events
| name | argument |
|----------------|-----------------------|
| `load` | GlslCanvas instance |
| `error` | Error |
| `textureError` | TextureError |
| `render` | GlslCanvas instance |
| `over` | MouseEvent |
| `out` | MouseEvent |
| `move` | { x:, y: } |
| `click` | MouseEvent |
---
### Methods
| name | parameters |
|---------------|-|
| `load` | fragment: string, vertex: string |
| `on` | eventName: string, callback: Function |
| `setTexture` | key: string, target: string or element, options:TextureOptions |
| `setUniform` | key: string, ...values: number or string |
| `setUniforms` | uniforms: { [key: string]: number[] or string } |
| `play` | |
| `pause` | |
| `toggle` | |
| `destroy` | |
___
## Including dependent files with `#include`
You can include other GLSL code using a traditional `#include "file.glsl"` macro.
```javascript
// example
#include "common/uniforms.glsl"
#include "common/functions.glsl"
void main(){
```
___
## Multiple buffers
You can use shader buffers by requiring definition with `#ifdef` or `defined` directly in `.glsl` code.
Just ask for `BUFFER_`N definition and a `u_buffer`N uniform will be created for you:
```glsl
uniform sampler2D u_buffer0;
#ifdef BUFFER_0
void main() {
vec4 color = texture2D(u_buffer0, uv, 0.0);
...
gl_FragColor = color;
}
#else
void main() {
vec4 color = texture2D(u_buffer0, uv, 0.0);
...
gl_FragColor = color;
}
#endif
```
___
## Vertex & Fragment shader
You can define both vertex and fragment shader on same file by requiring vertex definition with `#ifdef` or `defined` directly in `.glsl` code.
Just ask for `VERTEX` definition and the vertex shader will be created for you:
```glsl
#if defined(VERTEX)
// attribute vec4 a_position; // data/dolphin.obj
attribute vec4 a_position;
attribute vec4 a_normal;
attribute vec2 a_texcoord;
attribute vec4 a_color;
void main(void) {
v_position = a_position;
v_position = u_projectionMatrix * u_modelViewMatrix * v_position;
v_normal = u_normalMatrix * a_normal;
v_texcoord = a_texcoord;
v_color = a_color;
gl_Position = v_position;
}
// fragment shader
#else
void main() {
...
}
```
___
## Tips
You can change the content of the shader as many times you want. Here are some examples:
```javascript
// load only the fragment shader
let fragment = 'main() { gl_FragColor = vec4(1.0); }';
glsl.load(fragment);
// load a fragment and vertex shader
let vertex = 'attribute vec4 a_position; main(){ gl_Position = a_position; }';
glsl.load(fragment, vertex);
```
You can also send your custom uniforms to a shader with ```.setUniform('name', ...values)```. GlslCanvas will parse the value you provide to determine its type. If the value is a ```string```, GlslCanvas will parse it as the url of a texture.
```javascript
// assign .5 to 'uniform float u_brightness'
glsl.setUniform('u_brightness', 0.5);
// assign (.2,.3) to 'uniform vec2 u_position'
glsl.setUniform('u_position', 0.2, 0.3);
// assign a red color to 'uniform vec3 u_color'
glsl.setUniform('u_color', 1.0, 0.0, 0.0);
// load a new texture and assign it to 'uniform sampler2D u_texture'
glsl.setUniform('u_texture', 'data/texture.jpg');
```
___
### Examples
You can find some example to start at this [```page```](https://github.com/actarian/glsl-canvas/blob/master/docs/index.html).
Or you can see a live demo at this link [actarian.github.io/glsl-canvas/](https://actarian.github.io/glsl-canvas/)
___
### Collaborate
If you'd like to contribute to this code, you need to:
* Install [node and npm](https://nodejs.org/download/)
* Fork and clone [this repository](https://github.com/actarian/glsl-canvas)
```bash
git clone https://github.com/actarian/glsl-canvas.git
```
* Switch to glsl-canvas directory
```bash
cd glsl-canvas
```
* Install dependencies
```bash
npm install
```
* Run gulp for development and testing with livereload
```bash
gulp
```
* Build for production
```bash
gulp build --target dist
```
* Push to your local fork and make your pull request
___
*Pull requests are welcome and please submit bugs 🐞*
*Thank you for taking the time to provide feedback and review. This feedback is appreciated and very helpful 🌈*
[](https://gitHub.com/actarian/glsl-canvas/network/) [](https://GitHub.com/actarian/glsl-canvas/stargazers/) [](https://github.com/actarian?tab=followers)
* [Github Project Page](https://github.com/actarian/glsl-canvas)
*If you find it helpful, feel free to contribute in keeping this extension up to date via [PayPal](https://www.paypal.me/circledev/5)*
[](https://www.paypal.me/circledev/5)
___
## Contact
* Luca Zampetti <lzampetti@gmail.com>
* Follow [@actarian](https://twitter.com/actarian) on Twitter
[](https://twitter.com/actarian)
___
## Release Notes
Changelog [here](https://github.com/actarian/glsl-canvas/blob/master/CHANGELOG.md).
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