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One engine for the live frame, the offline render and the rest of a game
A live renderer with shadows, baked light, TAA, text drawn from vector outlines, effects and dynamic resolution, and a GPU path tracer for stills, clips and the light bake. Both paint with the same physically based material, the bake hands path-traced light to the live frame, and live ambient occlusion and contact shadows ground what rests on the floor.
pfx aims at 120 fps, 8.33 ms a frame. VRR (adaptive sync) is on or off, on by default, and the frame rate is a 60 fps cap, a 120 fps cap, Uncapped or Auto. A game starts Uncapped; the editor times its first 60 frames and picks Auto if their median misses 8.33 ms, Uncapped if it doesn't. Auto aims at 120 and settles to a steady lower rate when a scene can't hold it.
An empty shipped game is 33.7 MB with its content, against Godot's 73.5 MB and Bevy's 106.6 MB. The domain code pfx needs (the denoiser, the Sobol sampler, LZ4, JPEG, the resampler) is ported into it, not linked.
Against other engines
One tool, pfx, and a set of library crates a game links.
It builds scenes from recipes, edits them in its own editor, plays
them with a game's WebAssembly module, and runs the physics, sound,
input and Steam a game needs.
Rust developers making 3D games or flat 2D arcade games who want the frame, the render, the editor and the rest of a game from one engine they can read end to end, and app makers who want their interface drawn on the GPU. Generic by design: no game keeps its names, values or assets in pfx; each game owns its content.
What each part does today
pfx-trace renders stills, clips and the light bake on the GPU. It traces with hardware ray queries wherever the device offers them (Vulkan, DX12, Metal on Apple Silicon) and with its own BVH elsewhere, samples with Cycles' tabulated Sobol sequence, and stops each pixel when it has converged. Past four lights it picks one per bounce through a light tree ported from Cycles.
pfx-denoise is Intel Open Image Denoise 2.5.1's RT filter ported to wgpu compute: a traced colour with its albedo and normal go in, the clean colour comes out, equal to OIDN's own output to about 1e-5, so a final stops at 16 to 64 samples a pixel and a draft at 6 to 12.
Sprites, text and particles for 2D games and overlays, laid out once and scaled to any screen, from a 4K monitor to the Steam Deck's 1280×800. Under the swarm test's load it takes 0.36 ms of GPU at 4K.
pfx alone opens the window and
pfx <file.pitofx> opens that document in it: an outliner,
the live viewport with gizmos and picking, an inspector, a TOML panel with
highlighting and checks at line and column, a log and a traced preview,
on one undo history. F5 plays the open scene as a game in the
viewport, with a game's WebAssembly module in pfx's sandbox, and F8 puts the editor back exactly where it was. Its egui crates are reusable
on their own.
A .pitofx is pfx's own file for scenes, recipes and models:
TOML inside, each chunk checksummed and compressed with LZ4 on its own,
so a reader decodes only the chunks it needs. A recipe document holds the
recipe, every file it reads, its built glTF and the scene built from it,
so an unchanged document opens without a rebuild.
pfx build builds a recipe headless into a GLB and a scene,
the same bytes on every OS. People edit a document in the editor's inspector
or its TOML panel; scripts and agents edit it with pfx set and pfx get by dotted key, which write the edit and a fresh
build back in one atomic replace. Other tools exchange glTF with pfx through
pfx import
and pfx export.
A .pitofx is compressed, so plain
git diff says only Binary files differ.
Run pfx git setup once per clone, or let
pfx new run it inside a git repository, and
git diff, git log -p and
git show print it as TOML: one changed value is one
line, entries keep a fixed order so saves don't churn, and a
packed mesh or image is one line with its size and CRC-32, listed
without decompressing it. Merges stay binary.
Everything around the frame ships in the same workspace, each a crate a game links by tag.
pfx new, in its own editor:
cargo run --release -- edit.
The domain code pfx needs lives inside it
pfx is open source under the AGPL-3.0: free for open-source projects, learning and hobby work. Read it, fork it, and send issues and pull requests on GitHub. Closed products and services built on pfx take a licence: free under $200k of yearly revenue plus funding, Indie and Pro above it.
© Catalin Ilinca, AGPL-3.0-only, with licences for closed products; releases up to 3.1.1 remain MIT. The PITO MD name, the pfx name and its logo are © Catalin Ilinca, all rights reserved.
Every picture and clip on this page is pfx's own, rendered or captured from its neutral scenes and licensed with its code (pfx's NOTICE.md); the pfx gui and game-editor clips were recorded by pfx from its v3.0.1 tag, the terminal clips with prec, the loops encoded with pito-codecs and the charts drawn with pito-compare from the numbers pfx v3.1.2 measures. Type: Exo 2 by NDISCOVER ( SIL Open Font License 1.1 ) and JetBrains Mono by JetBrains ( SIL Open Font License 1.1 ), from pfx's theme.