Metatron

Introduction

Metatron is a physically based renderer unbiasedly simulating radiative transfer equation and spectral transport with Metal/Vulkan acceleration.

Resources

• Demo scenes at metatron-scenes.
• Scene exporter at metatron-exporter.

Features

• Spectrum
  • Sampled spectra are used for rendering.
  • RGB compatibility via J19.
  • Real world spectra are used for conductor, dispersion and color space definition.
• Medium
  • Null-scattering integral for heterogenous medium via MG19.
  • Phase function evaluation and sampling via HG41.
  • NanoVDB is supported for volume data.
• BSDF
  • Unified physical BSDF for diffuse, dielectric, conductor and plastic surface via TS67.
  • Microfacet model and importance sampling via TR75 and H18.
• Shape
  • Sphere as convenient bounding volume.
  • Mesh in various formats supported by assimp.
• Light
  • Delta light including parallel, point and spot light.
  • Environment light with image importance sampling.
  • Area light for shapes with emissive material. Spherical triangle sampling via A95.
  • Atomosphere with alien world support via HW12 and HW13. TGMM sky sampling via VV21.
• Sampler
  • Heitz sampler for fast convergence via HB19
  • Z Sobol sampler for visual quality via AW20
• Integrator
  • Unbiased ReSTIR PT with pairwise MIS via LK22
  • Metal/Vulkan acceleration thanks to hardware ray tracing and slang.
  • Remote preview of rendering intermediates via tev

Build

Metatron use nix with flakes for package management on Linux and Darwin.

nix build

Or use CMake with manual dependencies. Add prefix flag for runtime resource loading.

cmake --preset rel -DCMAKE_INSTALL_PREFIX=/usr/bin/ -DCMAKE_CXX_FLAGS="-march=native"
cmake --build build/rel --target install

Usage

Metatron can be used as a library. Use package output in flake.nix or copy package.nix to add metatron.

# flake.nix
{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    metatron.url = "github:tsssni/metatron";
  };
  outputs = {nixpkgs, metatron, ...}: let
    pkgs = import nixpkgs {
      system = "x86_64-linux";
      overlays = [
        (final: prev: {
          metatron = metatron.packages.default;
        })
      ];
    };
  in {
    # use pkgs.metatron somewhere
  };
}

Metatron will be linked as a shared library.

find_package(metatron REQUIRED)
target_link_libraries(renderer PUBLIC metatron)

Run

Run metatron-tracer -h for option documents.

metatron-tracer -s ~/metatron-scenes/classroom/ -o classroom.exr -a localhost:14158 -d gpu