# GLSL Imports Use `#include` to import GLSL functions from NPM packages, your files, or URLs. You do not need to copy shader code between nodes. `#include` works in [glsl](/docs/objects/glsl), [swgl](/docs/objects/swgl), [regl](/docs/objects/regl), and [hydra](/docs/objects/hydra) inside `setFunction`. It also works in [three](/docs/objects/three) through the `await glsl` tagged template. ## How It Works Before shader compilation, `#include` inserts GLSL source code at the include site. Patchies resolves the path, gets the source, and inserts it. ```glsl #include void mainImage(out vec4 fragColor, in vec2 fragCoord) { float n = snoise(vec3(uv * 4.0, iTime)); fragColor = vec4(vec3(n), 1.0); } ``` This example gets the `snoise` function from the [lygia](https://lygia.xyz) shader library. Patchies resolves includes automatically. ## Import Sources You can import GLSL code from three sources: ### NPM Packages Use angle brackets to import from shader libraries, such as lygia: ```glsl #include #include #include ``` The `.glsl` extension is optional. `` and `` are equivalent. ### Your Files Use double quotes and a `user://` path to import from [Virtual Filesystem](/docs/virtual-filesystem) files: ```glsl #include "user://my-shaders/utils.glsl" #include "user://sdf-functions.glsl" ``` Add `.glsl` files in the sidebar (`Ctrl/Cmd + B > Files`). Then include them in any shader node. ### URLs Use double quotes and a complete URL to import GLSL from the web: ```glsl #include "https://raw.githubusercontent.com/stegu/psrdnoise/main/src/psrdnoise2.glsl" ``` Patchies caches URL imports in memory for the session. It gets each URL once. ## Supported Objects `#include` works in five visual objects. Most of them preprocess your shaders automatically. | Object | How it works | | --- | --- | | [glsl](/docs/objects/glsl) | Auto-preprocessed before shader compilation | | [swgl](/docs/objects/swgl) | Auto-preprocessed in `FP`, `VP`, and `Inc` fields | | [regl](/docs/objects/regl) | Auto-preprocessed in `frag` and `vert` fields | | [hydra](/docs/objects/hydra) | Auto-preprocessed inside `setFunction` GLSL strings | | [three](/docs/objects/three) | Use `await glsl` tagged template or `processIncludes()` | ### Hydra Usage Use `#include` inside `setFunction` to add external GLSL to the Hydra shader pipeline: ```javascript osc() .setFunction({ type: "frag", glsl: ` #include vec4 myEffect(vec4 color, vec2 uv) { float n = snoise(vec3(uv * 4.0, time)); return vec4(vec3(n), 1.0); } `, }) .out() ``` ### Three.js Usage Three.js nodes cannot preprocess shaders because Patchies does not control `THREE.ShaderMaterial`. Use the `await glsl` tagged template: ```javascript const material = new THREE.ShaderMaterial({ fragmentShader: await glsl` #include void main() { float n = snoise(vec3(vUv * 4.0, time)); gl_FragColor = vec4(vec3(n), 1.0); } `, }) ``` All JavaScript visual objects provide the `glsl` tag and `processIncludes()` function. ## Try It ### Exercise — Use Lygia Noise in a GLSL Shader 1. Create a `glsl` object (`Enter` > type `glsl`). 2. Paste this code: ```glsl #include void mainImage(out vec4 fragColor, in vec2 fragCoord) { float n = snoise(vec3(uv * 5.0, iTime * 0.5)); fragColor = vec4(vec3(n * 0.5 + 0.5), 1.0); } ``` 3. Connect the object to `bg.out`. You should see animated simplex noise. ### Exercise — Share a Utility Across Nodes 1. Open the sidebar (`Ctrl/Cmd + B > Files`). 2. Create a file named `utils.glsl`. 3. Add this helper function: ```glsl vec3 palette(float t) { return 0.5 + 0.5 * cos(6.28318 * (t + vec3(0.0, 0.33, 0.67))); } ``` 4. In a `glsl` object, include and use the file: ```glsl #include "user://utils.glsl" void mainImage(out vec4 fragColor, in vec2 fragCoord) { fragColor = vec4(palette(uv.x + iTime * 0.2), 1.0); } ``` 5. Create a second `glsl` object. 6. Include the same file. Both nodes share the function. ## Nested Includes Included files can contain `#include` directives. Patchies resolves includes up to 32 levels deep. Circular includes produce an error. ## Caching - **NPM packages:** Patchies gets packages from a CDN and caches them for the session. - **VFS files:** Patchies reads files again after they change. - **URLs:** Patchies caches URLs for the session. Reload the page to get them again. ## Licensing: Lygia Shader Library Lygia uses the [Prosperity License](https://prosperitylicense.com/versions/3.0.0) and the [Lygia Patron License](https://lygia.xyz/license). Lygia is free for non-commercial use, including personal use and use in non-commercial organizations. For commercial use, purchase a license from Patricio Gonzalez Vivo on [GitHub Sponsors](https://github.com/sponsors/patriciogonzalezvivo). These requirements do not apply if your shaders do not import Lygia with `#include `. You can use Patchies without importing Lygia. ## See Also - [glsl](/docs/objects/glsl) — Create fragment shaders with Shadertoy-compatible uniforms. - [swgl](/docs/objects/swgl) — Create SwissGL shaders. - [regl](/docs/objects/regl) — Use WebGL with REGL. - [three](/docs/objects/three) — Create Three.js scenes. - [Virtual Filesystem](/docs/virtual-filesystem) — Manage files for `user://` imports.

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