This template demonstrates how to integrate WebGL shaders with [tldraw](https://github.com/tldraw/tldraw), creating dynamic backgrounds that respond to canvas interactions. It includes four complete examples and a reusable `WebGLManager` base class for building custom shader effects. ## Local development Install dependencies with `yarn` or `npm install`. Run the development server with `yarn dev` or `npm run dev`. Open `http://localhost:5173/` in your browser to see the app. ## What's included - **WebGLManager base class** ([`src/WebGLManager.ts`](src/WebGLManager.ts)) - Handles WebGL lifecycle, viewport synchronization, and animation loop integration with tldraw's reactive system - **Four example shaders** - Fluid simulation, rainbow gradients, dynamic shadows, and a minimal starter template - **Config panel components** ([`src/config-panel/`](src/config-panel/)) - Pre-built UI controls for adjusting shader parameters with localStorage persistence - **Full TypeScript support** - Strongly typed throughout Switch between examples using the toggle buttons in the tldraw style panel. ## Examples ### Fluid Simulation A real-time fluid simulation that creates dynamic flows from shape interactions. Based on Pavel Dobryakov's WebGL fluid implementation. - Navier-Stokes fluid dynamics - Shape movements create velocity-based splats - Configurable physics and visual effects **See:** [`src/fluid/`](src/fluid/) | [Documentation](src/fluid/fluid.md) ### Rainbow An animated gradient shader demonstrating time-based effects and uniform management. **See:** [`src/rainbow/`](src/rainbow/) ### Shadows Dynamic shadow casting from tldraw shapes using raymarching and signed distance fields. **See:** [`src/shadow/`](src/shadow/) ### Minimal A bare-bones template for starting new shader projects. Renders a solid color that adapts to dark mode. **See:** [`src/minimal/`](src/minimal/) | [Documentation](src/minimal/minimal-example.md) ## Architecture ### WebGLManager The `WebGLManager` class ([`src/WebGLManager.ts`](src/WebGLManager.ts)) provides the foundation for all shader examples. It handles: - WebGL2 context creation and lifecycle management - Automatic viewport synchronization with tldraw's canvas - Animation loop with lifecycle hooks: `onInitialize()`, `onUpdate()`, `onRender()`, `onDispose()` - Quality/resolution management - Integration with tldraw's reactive state system To create a custom shader, extend `WebGLManager` and implement the lifecycle hooks. See the minimal example for a starting point. ### Config Panel The config panel system ([`src/config-panel/`](src/config-panel/)) provides reusable UI components for creating interactive shader controls: - `ConfigPanel` - Collapsible container with reset functionality - `ConfigPanelSlider` - Numeric slider control - `ConfigPanelBooleanControl` - Checkbox control Config values are stored in reactive atoms and automatically persisted to localStorage. See [config-panel.md](src/config-panel/config-panel.md) for usage details. ### Renderer Pattern Each example follows this pattern: 1. Define a config interface extending `WebGLManagerConfig` in `config.ts` 2. Create a shader manager class extending `WebGLManager` 3. Write GLSL shaders (vertex and fragment) 4. Create a React renderer component using `useLayoutEffect` to initialize the manager 5. Build a config panel for live parameter adjustment 6. Register the renderer as tldraw's `Background` component See any of the example directories for complete implementations. ## Creating a custom shader The fastest way to create a custom shader is to copy the minimal example: ```bash cp -r src/minimal src/my-shader ``` Then customize the following files: - `config.ts` - Define your configuration parameters - `fragment.glsl` / `vertex.glsl` - Write your shader code - `MyShaderManager.ts` - Extend WebGLManager and implement rendering logic - `MyRenderer.tsx` - Create the React component - `MyConfigPanel.tsx` - Build UI controls Finally, register your shader in [`src/App.tsx`](src/App.tsx). For a detailed walkthrough, see [src/minimal/minimal-example.md](src/minimal/minimal-example.md). ## Integration with tldraw The `WebGLManager` has direct access to the tldraw editor instance, allowing you to: - Access shapes: `this.editor.getCurrentPageShapes()` - Listen to shape changes: `this.editor.store.listen()` - Get camera state: `this.editor.getCamera()` - Convert coordinates: `this.editor.pageToViewport()` - Track pointer position: `this.editor.inputs.getCurrentPagePoint()` The fluid simulation example ([`src/fluid/FluidManager.ts`](src/fluid/FluidManager.ts)) demonstrates shape integration in depth. ## Resources - [WebGL2 Fundamentals](https://webgl2fundamentals.org/) - WebGL tutorials - [The Book of Shaders](https://thebookofshaders.com/) - GLSL shader programming - [Shadertoy](https://www.shadertoy.com/) - Shader examples - [tldraw Documentation](https://tldraw.dev) - tldraw SDK docs ## License This project is provided under the MIT license found [here](https://github.com/tldraw/vite-template/blob/main/LICENSE.md). The tldraw SDK is provided under the [tldraw license](https://github.com/tldraw/tldraw/blob/main/LICENSE.md). ## Trademarks Copyright (c) 2024-present tldraw Inc. The tldraw name and logo are trademarks of tldraw. Please see our [trademark guidelines](https://github.com/tldraw/tldraw/blob/main/TRADEMARKS.md) for info on acceptable usage. ## Distributions You can find tldraw on npm [here](https://www.npmjs.com/package/@tldraw/tldraw?activeTab=versions). ## Contribution Found a bug? Please [submit an issue](https://github.com/tldraw/tldraw/issues/new). ## Community Have questions, comments or feedback? [Join our discord](https://discord.tldraw.com/?utm_source=github&utm_medium=readme&utm_campaign=sociallink). For the latest news and release notes, visit [tldraw.dev](https://tldraw.dev). ## Contact Find us on Twitter/X at [@tldraw](https://twitter.com/tldraw).