Phosph-rs

Work in Progress

A for fun path-tracing library.

This library provides some path-tracing shaders and an API to interact with them using wgpu's ray-tracing extensions.

API Design

Subject to change - Feedback welcome

This API is designed to provide raytracing shaders, but as little as possible else while still keeping interactions with the shaders easy to allow other tools around this.

API Usage

General Usage Notes

Path path_tracing provides path-tracing shaders while path debug provides debugging shaders.

Call pipeline_layout with the device and the number of BLASes to create a generic pipeline layout compatible with all shaders provided by this.

Material struct is for materials call Material::new with the texture coordinates for the three triangles, the texture index, the maximum emission brightness an optional refractive index, and a type, call descriptor on a slice of Materials.

Do not treat the shader qualities as your main quality / performance option, even when changing samples by the recommended changes, these do not change performance consistently.

Texture Loading

Call TextureLoader::new() or TextureLoader::default() to create a blank texture loader. Call either texture_loader.load with a diffuse texture file name and optional lit and attribute texture file names, or call texture_loader.load_from_bytes with the bytes of a diffuse texture, and optionally bytes of lit and attribute textures as well.

To get the raw textures out of the TextureLoader call texture_loader.raw which will consume this texture loader and output a struct containing the bytes of 3 cuboid textures (designed for wgpu's texture_2d_array) that are the diffuse texture array, the lit texture array, and the attributes texture array, this struct also contains the sizes for these three texture maps and any textures not included. Instead, to load the textures into wgpu textures call texture_loader.create_texture which will write these into wgpu textures and return a struct called WgpuTextures that can have as_bind_group called to convert it into a bind group, and it's bind group layout.

Note: the attribute texture has the red color channel for roughness, and the other color channels are unused

Camera

Call Camera::new with projection and view matrices or construct it with inverted projection and view matrices, call descriptor to get a buffer descriptor.

Roughness

This library supports four components in an attributes texture (x and y for the base material and z and w for a transparent surface in the same place)

Goal

Make a real time (20 - 30fps) path-tracer capable of being integrated into other renderers (yes, this is a lofty goal). Currently, reasonable picture quality (in an artificially lit environment - cornell box test scene, just outdoors higher quality) is only really possible with the Medium shader at ~256 samples per pixel with denoising (which currently gets ~4 fps).

Examples

Currently, this has one example: the cornell box scene. This can be run using either without a denoiser or with a denoiser by enabling the feature denoise which uses oidn (you may have to do some copying of oidn dlls if using this).

Features in development

Importance Sampling

Note that this is WIP and only partially functional