Spectre

Spectre plugin

Spectre, Kinogaki Studio's spectral path tracer, and the render engine on the SDK around it. The renderer itself knows no SDK: src/tracer/ (what it computes on the CPU), src/metal/ (the Metal backend, kernels compiled ahead of time from kernels/) and src/denoise/ (OIDN's trained weights run by our own code). The rest of the crate is the engine: its description, lights, shading nodes and starting materials, scene sync and the render thread, on the host's own Metal device. It is checked out at plugins/spectre in the Kinogaki Studio tree and builds only there.

unsafe is denied rather than forbidden here, and allowed only in src/metal/sys.rs and src/metal/sys/: the Metal API through objc2-metal, and wgpu's Metal hal (sys/hal.rs).

Docs. docs/SPECTRE.md: the engine's modules, settings, outputs, sync, motion, the render thread. The renderer: docs/DESIGN.md, docs/MATERIALS.md, docs/SPECTRA.md, docs/ANODIZED.md, docs/PERFORMANCE.md; the kernels' dialect in kernels/README.md. Writing an engine in general: the root's docs/plugins/RENDER-ENGINE.md.

The host math and its tests come from luce-render, the owner's own renderer. Its shader-graph bytecode is checked word for word against words dumped by running luce-render (tools/luce_render_graphs), and its Cornell box is rendered by both renderers for a statistical comparison (tools/luce_render_cornell).

Tests, run by the root's python3 tools/check_all.py:

• tests/tracer/: the renderer on the CPU (scene edits, trees, lights, cameras, spectra, shader graphs);
• tests/denoise/: the Metal denoiser against the CPU reference, and both against Open Image Denoise run on Spectre's renders (hand tests, with the OIDN release Studio's tools/fetch_data.py brings);
• the other files of tests/, mostly GPU tests (#[ignore = "gpu"], run by check_all.py --changed and --full): the engine, its lights, furnaces and closed forms, sync of each prim kind, instancing, motion, outputs, denoising, and the Cornell box against tests/references.

python3 tools/check_kernels.py compiles every kernel in every variant through glslangValidator (Vulkan 1.2 SPIR-V) and xcrun metal (MSL) on the Mac, so the Vulkan source compiles though no backend runs it yet; tool versions are in kernels/TOOLS.md.