v0.1.0

Offset litho, as an FFGL effect for Resolume Arena and Avenue. A printed picture is four plates and a press: cyan, magenta, yellow and black, each a lattice of dots at its own screen angle, laid down by a press that never quite registers them and wanders as it runs. Rosettes, moiré, colour fringing, dot gain and overprint are consequences of those two things rather than textures laid over the picture.

What is verified

By tools/verify.sh on an M4 Max, macOS 26.4, on 2026-09-21:

• The GLSL spot functions against their C++ originals: 264,196 comparisons, 0 disagreements past 1e-5, largest difference 1.79e-07.
• Printed area against the dot-gain curve: worst band off by 0.0099 of full area over six shape-and-gain cases.
• Screen angles recovered from about 1,550 dot centroids to within 0.06°; pitch 15.95–15.98 px for a 16 px screen.
• Registration offsets of (+3, −2) and (+0.5, +0.25) px move every dot by exactly that, worst disagreement 0.0491 px.
• Overprint: C over Y, C over M, M over Y and all three — every pixel exact, 0/255.
• Press wander is bounded (9.545 of 10 px), smooth (0.2174 px/frame) and exactly zero at zero drive.
• All 44 swept parameters measurably change the picture.
• Render cost 0.15 ms/frame at 720p, 0.23 at 1080p, 0.50 at 4K — macOS figures only.
• Registered, loaded and instantiated in Resolume Arena 7.27.1 (build 15990) on Windows on 2026-09-21, with the shaders compiling — on a software rasteriser (Mesa llvmpipe), not a GPU.

What is not

• Never run on a GPU in Resolume, never instantiated in Arena on macOS, and no frame timing taken on Windows.
• Applied to the composition rather than a clip, so the proof is the diag log. Arena drew an inspector, but nothing in it was checked beyond its appearing, so how the parameters present is untested.
• No real audio has reached it in a host, so Resolume's 64-bin FFT mapping is assumed, and its clock unit in Arena is unconfirmed.
• No long session, no composition save or reload, no preset recall in the host.
• No user guide, so the About block carries no guide link. No browser demo, no OpenFX port.

The macOS build is signed and notarised; the Windows build is unsigned, so SmartScreen warns once.

Full Changelog: https://github.com/stoatworks-labs/rosette/commits/v0.1.0