Pyxis

A C++23 real-time path tracer (NVRHI/Vulkan, Slang shaders, Windows-only v1) inspired by Autodesk Aurora. Primary scene target: render the Disney Moana Island USD scene end-to-end on a single Windows workstation.

Pyxis is a previewer, not a production renderer. It is not an Arnold/RenderMan/Cycles competitor. No render farm, no production color management, no animation playback in v1. Anything outside that scope goes through the RFC process before being added.

The canonical engineering plan lives in plan_final.md. It is the source of truth for architecture, public API, coding rules, milestones, and governance. The repo-root CLAUDE.md is a section index map for that plan.

Status

Pre-release. Following milestones M0..M11 from plan_final.md §38 / §41:

• M0 — Skeleton: build system green, pyxis.exe opens a Vulkan device, SceneWorld Flecs phase pipeline initialised.
• M3 — Slang path-trace box (single cube, BLAS+TLAS).
• M8a — Moana subset render (≤1M tris, nightly regression seed).
• M11 — Profiling polish (1.0.0).

Build (target)

Pyxis targets Windows 10/11 x64 with clang-cl 17+, Vulkan SDK 1.3.x, vcpkg manifest mode, CMake 3.27+. See _documentation/getting_started.md (post-M11) for the canonical walkthrough.

One command, fully automatic. From a clean clone, _tools/init.ps1 drives the whole pipeline — bootstrap missing prerequisites (it self-elevates for the Vulkan SDK install; approve the one UAC prompt), acquire nv-usd 25.11 via Packman, configure, and build to a runnable pyxis.exe:

pwsh _tools/init.ps1            # prereqs -> nv-usd -> scenes -> configure -> build
pwsh _tools/init.ps1 -Stage configure   # just (re)configure
pwsh _tools/init.ps1 -WithClangTidy     # build with the §37 clang-tidy gate on

The scenes stage fetches the optional regression scenes into resources/scenes/ (gitignored): the OpenPBR Shader Playground downloads automatically from the ASWF DPEL GitHub (~1.9 GB); the World Lobby has no stable public URL — drop Collected_World_Lobby.zip into Downloads\ or pass -WorldLobbyUrl <mirror> (or set PYXIS_WORLD_LOBBY_URL). Missing scenes only skip their fixtures; the build is unaffected.

Or run the steps by hand. _tools/required_install.ps1 is a read-only dev-box doctor; add -Install to bootstrap every missing piece (Visual Studio Build Tools, LLVM, CMake, Ninja, Vulkan SDK, Python, vcpkg) — it self-elevates as needed:

.\_tools\required_install.ps1            # doctor (green/red checklist)
.\_tools\required_install.ps1 -Install   # bootstrap missing deps

Then:

pwsh _tools/omniverse/setup.ps1   # one-time nv-usd 25.11 + Python 3.12 (Packman)
cmake --preset dev
cmake --build --preset dev-release

Layout

Path	Purpose
plan_final.md	Canonical design document (read this first)
CLAUDE.md	Section-index map for the plan (auto-loaded by Claude Code)
_cmake/	CMake helpers + clang-cl toolchain + custom triplets
_tools/	Scripts — install, license audit, regression harness, perf bisect, …
_documentation/	User-facing docs + RFCs + postmortems
_pipelines/	CI definitions
sources/pyxis_platform/	Vulkan/NVRHI device, OS, file I/O, logging (SHARED)
sources/pyxis_renderer/	Renderer core, public API, SceneWorld (Flecs), passes
sources/pyxis_material_translation/	UsdPreviewSurface / MaterialX / RenderMan → OpenPBR
sources/pyxis_hydra/	Hydra 2.0 render delegate (ingest adapter)
sources/pyxis_usd_ingest/	Direct USD walker (ingest adapter; no Hydra)
sources/pyxis_app/	Single executable: viewer + headless
resources/shaders/	Slang sources
tests/	gtest unit tests + Python regression harness
thirdparty/	Vendored or fetched third-party (NVRHI, Slang, OpenUSD, …)

Licensing

Pyxis is distributed under the Apache License, Version 2.0 — see LICENSE.

NOTICE aggregates third-party attributions. CI asserts NOTICE byte-equals NOTICE.generated (produced by _tools/license_audit.py); any drift fails the build. Adding a dep with a non-Apache-compatible licence (GPL, AGPL, SSPL) fails the same step.

The third-party-licence mix is constrained to MIT / BSD-2 / BSD-3 / Apache-2 / Zlib / public-domain components only.

Contributing

See CONTRIBUTING.md for build steps, code-style rules, commit-message convention (Conventional Commits 1.0.0), and the PR / reviewer checklists. Non-trivial design changes go through the RFC process under _documentation/rfcs/ (plan §44).

Privacy

Pyxis ships zero telemetry (plan §47.3 / §48.1). No phone-home, no anonymous usage stats, no automatic crash-dump upload. Configuration files and per-run reports stay on the local machine.