Phenomenon


Phenomenon is a very small, low-level WebGL library that provides the essentials to deliver a high performance experience. Its core functionality is built around the idea of moving millions of particles around using the power of the GPU.

#### Features:

- Small in size, no dependencies
- GPU based for high performance
- Low-level & highly configurable
- Helper functions with options
- Add & destroy instances dynamically
- Dynamic attribute switching

Want to see some magic right away? Have a look here!

Install

``
$ npm install --save phenomenon
`

Usage

`js
// Import the library
import Phenomenon from 'phenomenon';

// Create a renderer
const phenomenon = new Phenomenon(options);

// Add an instance
phenomenon.add("particles", options);
`

> For a better understanding of how to use the library, read along or have a look at the demo!

API

$3

Returns an instance of Phenomenon.

> Throughout this documentation we'll refer to an instance of this as renderer.

#### options.canvas
Type: HTMLElement

Default: document.querySelector('canvas')


The element where the scene, with all of its instances, will be rendered to. The provided element has to be otherwise it won't work.

#### options.context
Type: Object

Default: {}


Overrides that are used when getting the WebGL context from the canvas. The library overrides two settings by default.

| Name | Default | Description |
| --------- | --------| --------------------------------------------------------------------------------------------------------------------------------------- |
| Alpha | false | Setting this property to true will result in the canvas having a transparent background. By default clearColor is used instead. |
| Antialias | false | Setting this property to true will make the edges sharper, but could negatively impact performance. See for yourself if it's worth it! |

> Read more about all the possible overrides on MDN.

#### options.contextType
Type: String

Default: webgl

The context identifier defining the drawing context associated to the canvas. For WebGL 2.0 use webgl2.

#### options.settings
Type: Object

Default: {}


Overrides that can be used to alter the behaviour of the experience.

| Name | Value | Default | Description |
| ---------------------------------------- | ---------- | --------------- | --------------------------------------------------------------------------- |
| devicePixelRatio | number | 1 | The resolution multiplier by which the scene is rendered relative to the canvas' resolution. Use window.devicePixelRatio for the highest possible quality, 1 for the best performance. |
| clearColor | array | [1,1,1,1] | The color in rgba that is used as the background of the scene. |
| clip | array | [0.001, 100] | The near and far clip plane in 3D space. |
| position | number | {x:0,y:0,z:2} | The distance in 3D space between the center of the scene and the camera. |
| shouldRender | boolean | true | A boolean indicating whether the scene should start rendering automatically. |
| uniforms | object | {} | Shared values between all instances that can be updated at any given moment. By default this feature is used to render all the instances with the same uProjectionMatrix, uModelMatrix and uViewMatrix. It's also useful for moving everything around with the same progress value; uProgress. |
| onSetup(gl) | function | undefined | A setup hook that is called before first render which can be used for gl context changes. |
| onRender(renderer) | function | undefined | A render hook that is invoked after every rendered frame. Use this to update renderer.uniforms. |

$3

Update all values that are based on the dimensions of the canvas to make it look good on all screen sizes.

$3

Toggle the rendering state of the scene. When shouldRender is false requestAnimationFrame is disabled so no resources are used.

#### shouldRender
Type: Boolean

Default: undefined


An optional boolean to set the rendering state to a specific value. Leaving this value empty will result in a regular boolean switch.

$3

This function is used to add instances to the renderer. These instances can be as simple or complex as you'd like them to be. There's no limit to how many of these you can add. Make sure they all have a different key!

#### key
Type: String

Default: undefined


Every instance should have a unique name. This name can also be used to destroy the instance specifically later.

#### settings
Type: Object

Default: {}


An object containing overrides for parameters that are used when getting the WebGL context from the canvas.

| Name | Value | Default | Description |
| ----------- | ---------- | ------------ | --------------------------------------------------------------------------- |
| attributes | array | [] | Values used in the program that are stored once, directly on the GPU. |
| uniforms | object | {} | Values used in the program that can be updated on the fly. |
| vertex | string | - | The vertex shader is used to position the geometry in 3D space. |
| fragment | string | - | The fragment shader is used to provide the geometry with color or texture. |
| multiplier | number | 1 | The amount of duplicates that will be created for the same instance. |
| mode | number | 0 | The way the instance will be rendered. Particles = 0, triangles = 4. |
| geometry | object | {} | Vertices (and optional normals) of a model. |
| modifiers | object | {} | Modifiers to alter the attributes data on initialize. |
| onRender | function | undefined | A render hook that is invoked after every rendered frame. |

> Note: Less instances with a higher multiplier will be faster than more instances with a lower multiplier!

$3

Remove an instance from the scene (and from memory) by its key.

$3

Remove all instances and the renderer itself. The canvas element will remain in the DOM.

$3

Dynamically override an attribute with the same logic that is used during initial creation of the instance. The function requires an object with a name, size and data attribute.

> Note: The calculation of the data function is done on the CPU. Be sure to check for dropped frames with a lot of particles.

Attributes can also be switched. In the demo this is used to continue with a new start position identical to the end position. This can be achieved with .prepareBuffer(attribute) in which the data function is replaced with the final array.

Examples

1. Particles
2. Types
3. Transition
4. Easing
5. Shapes
6. Instances
7. Movement
8. Particle cube
9. Dynamic intances

Contribute

Are you excited about this library and have interesting ideas on how to improve it? Please tell me or contribute directly! 🙌

`
npm install > npm start > http://localhost:8080
``

License

MIT © Colin van Eenige