[git-chad]

Stacked on #174. Part of the V3 stack (parent #150); nothing merges to main until the plan is complete.

What

A new Signal Rot effect layer (Distort, after Slice). It consolidates Signal rot and scanner drag (6.1 #4) into one layer (roadmap 3.4). It's a single pass that remaps where each pixel samples, along the axis set by Streaks (vertical or horizontal):

• Drag: held segments with wavy fronts drag the image into long streaks. Stretch varies the scan speed; Wobble makes the image snake sideways.
• Tear: ragged bands shift, and Dropout lifts parts of them off to a paper color.
• Signal: Chroma Shift, Crush (fewer tone levels) and Line Noise (scan lines jump and flicker).
• Motion: Speed 0 freezes the damage; above 0 it rots over time. Seed rearranges it.

Three styles: Scanner Drag (default, reference 13), Signal Rot, Torn Scan. It's distinct from Slice (blocky offsets), CRT (display) and Circuit Bent (bent scanlines).

Cost: 3 texture samples per pixel, no feedback buffers.

References

Reference 13 was reviewed against renders of every style. The first renders showed two problems, both fixed before review:

• Line noise and chroma ran along the wrong axis.
• Drag fronts came out rectangular and sawtooth.

The streaks are only as rich as the photo: a flat sky gives flat streaks.

Tests

bun run check passes, and the full bun run test:composition suite passes. signal-rot.mjs adds 56 checks:

• Neutral settings reproduce the input exactly.
• Full drag holds columns into streaks, and rows in horizontal mode.
• Tear shifts bands, dropout fills part of them, and chroma separates channels.
• Full crush leaves at most four levels.
• Speed 0 stays frozen, and speed above 0 animates and requests continuous rendering.
• Every style gives finite output.
• Editor/runtime parity, history, duplication, save/reopen, shader export and runtime pixel parity.

Manual check: tests/composition/SIGNAL-ROT-MANUAL-QA.md.

Open

• Tuning of defaults (visually accepted by the user; Tape Wobble removed at their request).
• Nothing accumulates between frames, so there are no feedback trails.
• Cost hasn't been measured on native hardware.

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated
shader-lab	Ready	Preview	Oct 1, 2026 2:03pm UTC

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge with no actionable defects identified.

Summary

The PR adds the Signal Rot distortion layer across the editor and React runtime.

• Implements drag, tear, dropout, wobble, chroma, crush, line-noise, seed, and motion controls in matching editor/runtime passes.
• Adds four styles, catalog/sidebar integration, shader-export support, documentation, preview media, and composition coverage.
• No actionable correctness, security, or repository-rule violations were identified.

_{Reviews (1) · Last reviewed commit: "Add a Signal Rot effect layer for scanne..."}