spuristo

Spuristo is a CPU based multithreaded rendering engine. Made with the goal of learning Rust and physically based rendering :) The renderer is designed to be as modular as possible such that adding new features or algorithms is straightforward.

Features

• Area light sampling
• Path tracing with next event estimation
• Microfacet BSDF with multiple importance sampling and GGX distribution
• Disney diffuse BRDF with energy normalization used in Frostbite
• Vertex and normal parsing from .OBJ files
• kd-tree that handles meshes containing up to 5 million triangles with reasonable render times
• Tone mapping
• Perlin noise generator

Usage

Once the repository is cloned, the examples/ folder contains scenes. To run the hello_sphere.rs example execute the command:

cargo run --example hello_sphere

The renderer can be configured either through its setter methods or partially through the CLI:

Usage: hello_sphere [-s <samples>] [-t <threads>] [-w <width>] [-h <height>] [-d]

Optional CLI configuration of renderer. Renderer setter methods have priority.

Options:
  -s, --samples     number of samples per pixel (defaults to 1)
  -t, --threads     number of threads used (defaults to all)
  -w, --width       width of the rendered image (defaults to 1000)
  -h, --height      height of the rendered image (defaults to 1000)
  -d, --direct      use direct light integrator instead of path tracing.
  --help            display usage information

Using the API

The hello_sphere.rs example is written as follows:

use spuristo::*;
use spuristo::tracer::*;
use glam::DVec3;

fn main() -> Result<(), png::EncodingError> {
    let camera = Camera::default();
    let mut scene = Scene::default();

    scene.add(
        Plane::new(
            DVec3::NEG_Y,
            DVec3::Y,
            Material::diffuse(Texture::Solid(srgb_to_linear(190, 200, 210)))
        )
    );

    scene.add(
        Sphere::new(
            8.0 * DVec3::Y + 1.5 * DVec3::NEG_Z,
            4.0,
            Material::Light(Texture::Solid(srgb_to_linear(255, 255, 255)))
        )
    );

    scene.add(
        Sphere::new(
            DVec3::ZERO,
            1.0,
            Material::diffuse(Texture::Solid(srgb_to_linear(0, 0, 255)))
        )
            .scale(0.3, 0.3, 0.3)
            .translate(0.0, -0.7, -1.5)
    );

    let mut renderer = Renderer::new(scene, camera);
    renderer.set_samples(36);
    renderer.render()
        .save("hello.png")
}

And it renders an image of a blue sphere:

TODO/WIP

• Finalize refraction of transparent microfacet materials
• Isotropic mediums (fog, smoke, clouds, ...)
• Multiple importance sampling in path tracer
• Sampling from distribution of visible normals in microfacets
• (Texture mapping)
• (Bidirectional path tracing)
• (Subsurface scattering)

References

• Physically Based Rendering
• Ray Tracing in One Weekend
• Moving Frostbite to Physically Based Rendering
• Eric Veach's PhD Thesis
• ekhzang/rpt

Gallery

Stanford dragon with 871K triangles. Rendered in 45 minutes using 30 threads of Intel Xeon Gold 6248. 1024 samples per pixel.

Cornell box displaying reflection and refraction. Rendered in 50 minutes using 30 threads of Intel Xeon Gold 6248. 4096 samples per pixel.

Statue of Nefertiti with 6.4M triangles. Rendered in 196 minutes using 40 threads of Intel Xeon Gold 6248. 1024 samples per pixel.