# Force Directed Graph

GPU supercharged attraction-graph visualizations for the web built on top of [Three.js](http://threejs.org). Importable as an ES6 module.

1. 🧮 Simulation computed on GPU via render targets
2. 🕸️ Accepts thousands of nodes and links
3. 🎨 Configurable point and link colors
4. 〰️ GPU-expanded antialiased line rendering with configurable width
5. 📦 Single library dependent (Three.js)
6. 🧩 Three.js scene compatible object
7. 📝 Simple data schema to populate compatible with d3.js JSON samples
8. 🧊 2d & 3d simulation modes
9. 🦺 WASM workers to generate textures

Visit the hosted [project page](https://jonobr1.com/force-directed-graph/) for a running demo.

## Usage

```
npm install --save three @jonobr1/force-directed-graph
```

### Import in ES6 environment

```javascript
import { ForceDirectedGraph } from '@jonobr1/force-directed-graph';
```

### Data Schema (`constructor` and `set`)

> Reference: The accepted `nodes` / `links` structure is inspired by the D3 force-directed graph data format: [@d3/force-directed-graph-component](https://observablehq.com/@d3/force-directed-graph-component).

The same data object shape is accepted by:

- `new ForceDirectedGraph(renderer, data)`
- `fdg.set(data[, callback])`

> [!TIP]
> It is recommended to use `set` and update setters in the callback or after the promise resolves. E.g: `fdg.set(data).then(() => {fdg.linewidth = 2})`

```ts
type GraphData = {
  nodes: NodeData[];
  links: LinkData[];
};

type NodeData = {
  id: string | number; // Required, unique per node
  x?: number;          // Optional initial / target x position
  y?: number;          // Optional initial / target y position
  z?: number;          // Optional initial / target z position
  isStatic?: boolean;  // Optional, pins node when true
  color?: THREE.ColorRepresentation; // Optional Three.js color input
  image?: string | HTMLImageElement; // Optional image URL or image element
  label?: string | number; // Optional canvas-atlas text label
  labelPriority?: number; // Optional label ranking override
  size?: number        // Optional size for per-node sizing
};

type LinkData = {
  source: string | number; // Node reference (must match a node.id)
  target: string | number; // Node reference (must match a node.id)
};
```

> [!NOTE]
> - `nodes` and `links` are both required.
> - `source` / `target` are resolved by node `id`.
> - If `x`, `y`, or `z` is omitted, a random initial position is assigned.
> - If a node defines at least two of `x`, `y`, `z`, those values also become that node's target position when `pinStrength > 0`.
> - `isStatic` defaults to `false`.
> - If `color` is omitted, the node defaults to white.
> - `set(data[, callback])` returns a `Promise` that resolves when geometry/textures are ready.
> - `obscurity` is label-density control: `0` shows all labels, `0.75` targets roughly 25% visible labels, and `1` hides all labels. The active subset is now chosen from graph topology and priority, not camera clipspace placement.
> - `fdg.labels.alignment` (`'center' | 'left' | 'right'`) and `fdg.labels.baseline` (`'top' | 'middle' | 'bottom'`) change label anchoring live.
> - `fdg.labels.offset` (`THREE.Vector2`) adds extra label padding in label-space x/y.
> - `fdg.labels.near` (camera-space distance, default `0`) discards labels at or closer than that depth, which is useful when `sizeAttenuation` makes nearby labels too large.
> - `fdg.labelsInheritColor` toggles whether labels use each node's `color`, and `fdg.labelColor` tints all labels uniformly on top of the white label atlas.
> - `fdg.labels.fontSize` scales the rendered label planes without rebuilding the atlas; `fdg.labels.fontFamily` rebuilds the atlas with a new CSS font stack.
> - `fdg.refreshLabels()` rebuilds label atlas data after mutating node labels, priorities, sizes, or colors in-place.
> - `fdg.getPerformanceInfo()`, `fdg.isWorkerProcessingAvailable()`, and `fdg.isWasmAccelerationAvailable()` expose worker / WASM capability state.

### Selected Instance API

- `fdg.pinStrength`: controls how strongly nodes are attracted toward their target positions derived from `x`, `y`, `z`.
- `fdg.refreshLabels()`: reparses labels from current node data and updates or removes the labels mesh as needed.
- `fdg.labels`: returns the labels mesh when labels exist, otherwise `null`.
- `fdg.getPerformanceInfo()`: returns `{ workerSupported, workerReady, wasmReady, pendingRequests }`.

### Load Script in HTML file:

This example creates 512 nodes and links them randomly like big snakes.

```html
<!doctype html>
<html>
  <head>
    <meta charset="utf-8">
  </head>
  <body>
    <script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
    <script type="importmap">
      {
        "imports": {
          "three": "https://cdn.jsdelivr.net/npm/three/build/three.module.js",
          "three/examples/jsm/misc/GPUComputationRenderer.js": "https://cdn.jsdelivr.net/npm/three/examples/jsm/misc/GPUComputationRenderer.js",
          "@jonobr1/force-directed-graph": "https://cdn.jsdelivr.net/npm/@jonobr1/force-directed-graph/build/fdg.module.js"
        }
      }
    </script>
    <script type="module">

      import * as THREE from 'three';
      import { ForceDirectedGraph } from '@jonobr1/force-directed-graph';

      const renderer = new THREE.WebGLRenderer({ antialias: true });
      const scene = new THREE.Scene();
      const camera = new THREE.PerspectiveCamera();

      camera.position.z = 250;

      // Generate some fake data
      const amount = 512;
      const data = {
      nodes: [],  // Required, each element should be an object
      links: []   // Required, each element should be an object
                  // with source and target properties that are
                  // ids of their connecting nodes
      };

      for (let i = 0; i < amount; i++) {

        data.nodes.push({ id: i });
        if (i > 0) {
          data.links.push({ target: Math.floor(Math.random() * i), source: i });
        }

      }

      const fdg = new ForceDirectedGraph(renderer, data);
      scene.add(fdg);

      setup();

      function setup() {
        renderer.setClearColor('#fff');
        document.body.appendChild(renderer.domElement);
        window.addEventListener('resize', resize, false);
        resize();
        renderer.setAnimationLoop(render);
      }

      function resize() {

        const width = window.innerWidth;
        const height = window.innerHeight;

        renderer.setSize(width, height);
        camera.aspect = width / height;
        camera.updateProjectionMatrix();

      }

      function render(elapsed) {
        fdg.update(elapsed);
        renderer.render(scene, camera);
      }

    </script>
  </body>
</html>
```

> [!WARNING]
> Due to the reliance on the GPU compute rendering, this project is not built for node.js use.

A free and open source tool by [Jono Brandel](http://jono.fyi/)