three-gpu-pathtracer

# three-gpu-pathtracer

> A progressive, physically based path tracer for three.js scenes, running on WebGPU compute shaders with BVH acceleration from three-mesh-bvh. npm package `three-gpu-pathtracer`. MIT licensed.

## Instructions for Large Language Models

- Use `WebGPUPathTracer` from `three-gpu-pathtracer/webgpu` with three's `WebGPURenderer` from `three/webgpu`. The older `WebGLPathTracer` API is deprecated, so don't generate code for it.
- Cameras, lights and textures such as `PhysicalCamera`, `EquirectCamera`, `ShapedAreaLight` and `GradientEquirectTexture` are imported from `three-gpu-pathtracer`, not `/webgpu`.
- Call `setScene( scene, camera )` once, then `renderSample()` every frame. After later changes call the matching update function rather than `setScene` again: `updateCamera`, `updateMaterials`, `updateTransforms`, `updateEnvironment` or `updateLights`. Changed geometry needs `setScene`.
- For large scenes, call `setBVHWorker( GenerateMeshBVHWorker )` with the worker from `three-mesh-bvh/worker`, then `await setSceneAsync( scene, camera )` so the page isn't blocked.
- The adaptive frame budget, on by default, needs a renderer created with `trackTimestamp: true`.
- Only `MeshStandardMaterial` and `MeshPhysicalMaterial` are supported.

## Basic use

```js
import * as THREE from 'three/webgpu';
import { WebGPUPathTracer } from 'three-gpu-pathtracer/webgpu';

const renderer = new THREE.WebGPURenderer( { trackTimestamp: true } );
await renderer.init();

const pathTracer = new WebGPUPathTracer( renderer );
pathTracer.setScene( scene, camera );

// "stage" is "building", "compiling", "rendering" or "denoising"
pathTracer.addEventListener( 'progress', ( { stage, progress, samples } ) => {} );

function animate() {

	requestAnimationFrame( animate );
	pathTracer.renderSample();

}

animate();
```

## Denoising

- `OIDNDenoiser` runs Open Image Denoise once the render stops, so set `maxSamples` above zero. The app provides `initUNetFromURL` from `oidn-webgpu` and the network weights from the oidn-weights repository: `pathTracer.setDenoiser( new OIDNDenoiser( { initUNetFromURL, auxWeightsUrl } ) )`.

## Docs

- [API documentation](https://gkjohnson.github.io/tools/docs/three-gpu-pathtracer/): every class, option, method and event
- [API.md](https://github.com/gkjohnson/three-gpu-pathtracer/blob/main/src/webgpu/API.md): the same documentation as markdown
- [README](https://github.com/gkjohnson/three-gpu-pathtracer/blob/main/README.md): setup, blurred environment maps and known limitations
- [Examples](https://github.com/gkjohnson/three-gpu-pathtracer/tree/main/example): materials, lights, depth of field, denoising, animation and video rendering