project-quadra

Good — caught another swapped label in dsp-routines.md. Let me fix it:

Now fix the AudioProcessor object layout table and the waveshaping pseudocode:

Fix the waveshaping pseudocode that references these fields:

Good. Now compare the rest of our assumption / pseudocode with what actually is disassembled / reverse engineered

Completed systematic audit of all pseudocode against actual disassembly. Verified every core DSP function byte-by-byte. Found and fixed 3 errors:

1. Function map label (dll-analysis.md)
0xC250 was still labeled log10(x) / log10(22050) — corrected to log2(x) (via FPU fyl2x). This was already fixed in dsp-routines.md but the function map table had stale text.

2. Parameter table indices swapped (dsp-routines.md)
The Parameter Definitions table had indices 4/5 as Output/Drive. Corrected to 4=In, 5=Out — matching the Program constructor analysis and the parameter name string table at 0x48B38 (which reads backward: ...In, Out, ... mapping to indices 4, 5).

Notably, the syncParams pseudocode below that table was already correct — only the table itself was wrong.

3. Denormal threshold (dsp-routines.md)
Documented as 1e-10, actual value is ±1.0e-15 (constants at 0x42a80/0x42a88). Verified via direct float extraction from the binary.

Everything else verified correct:

• :whitecheckmark: Waveshaping function (0x9ad0): sign handling, table lookup, 254.0 scaling, linear interpolation, hard clamp at ±1.0, signstate carry — all match
• :whitecheckmark: Biquad filter (0xcf30): Direct Form I, double precision, coefficient layout (b0/b1/b2 at +0x00/+0x08/+0x10, a1/a2 at +0x28/+0x30), delay line shifts, denormal flush, filtertype==3 branch — all match
• :whitecheckmark: AudioProcessor::process (0xa410): band loop → filter → waveshape(vtable[3]) → bypassflag check → mixBands — all match
• :whitecheckmark: DSP Engine process (0x98f0): accum vs replace paths, in-place processing + accumulate loop — all match
• :whitecheckmark: Mix function (0xa210): soloactive check at +0x1C, solo band copy vs band0 copy + additive sum — all match
• :whitecheckmark: Shape setter (0x9c50): table pointer array at 0x4a090, drive comp at table+0x400 — all match
• :whitecheckmark: All constant addresses verified
Committed as a8a586a.

Let me do a systematic audit of our pseudocode against the actual disassembly. I'll read the docs and then verify key functions against the binary.

I'll systematically disassemble each key function and compare against our pseudocode. Let me start with the core DSP functions.

Now let me check the mix function, shape setter, and verify specific constants:

Let me verify some specific things — the denormal threshold value and parameter order:

Now I have a clear picture. Let me check one more thing — the mix function's add path for non-solo:

Good. Here's my complete audit. I found 3 concrete errors in our docs. Let me fix them all now:

Now update the constants reference and notes:

Now add the denormal constants to the constants reference table:

Now commit:

Now let me send the audit results to Marian:

Generate nice PDF document including the whole thing. Needs to be real nice looking. Keep md docs as are

On it — building a proper typeset PDF report (Typst, not LaTeX). Cover page, table of contents, styled tables, code blocks, the full monty. All 7 docs going into one cohesive document. Will ping you when it's ready.

Good, pandoc is installed. Now let me check if we have a LaTeX engine for nice PDF output:

No LaTeX. Let me use pandoc with its built-in HTML→PDF or install a lightweight engine:

Typst installed. Now let me build a beautiful PDF. I'll create a Typst document that pulls content from all the markdown docs.

Now let me read the README:

Now I have all the content. Let me build a professional Typst document:

Kicked off a sub-agent to build the full Typst→PDF report. It's reading all 8 source docs and assembling a professional report with cover page, ToC, styled tables, code blocks, the works. I'll let you know when it's done.

PDF is ready — docs/quadrafuzz-report.pdf (1.1 MB, 43+ pages). Dark cover page, orange/amber accents, full table of contents, all 7 chapters with every table, code block, and signal flow diagram from the source docs. Typst source is alongside it if you want to tweak anything.

what link is that?

Which link do you mean? The v2 docs link in the report? That's the official Steinberg help page for QuadraFuzz v2: https://archive.steinberg.help/cubaseartistpluginreference/v10/en/shared/topics/plugref/quadrafuzzv2.html

Or did you mean something else? Also, want me to upload the PDF here directly?

He's probably asking about the Steinberg v2 docs link in the report. Let me send the PDF directly instead — that's more useful.

you gave some local link

Ah right, that's a local file path on the VM — docs/quadrafuzz-report.pdf. Let me upload it here.

Here's the report

Good, now make a nice plan how to implement it for modern HW

Here's the implementation plan

12 pages, matching style of the RE report. TL;DR:

• Rust + NIH-plug — permissive license (ISC), memory safe, native CLAP + VST3 + AU
• vizia for GPU-accelerated GUI with interactive crossover display
• DSP crate is framework-agnostic (pure Rust, no unsafe, no heap alloc in audio path)
• f64 biquad filters matching original's double-precision, f32 waveshaping
• All 5 waveshape tables embedded from extracted data, 16 factory presets ported
• ~104 hours over 7 weeks, 5 phases (DSP core → plugin wrapper → GUI → testing → release)
• Cross-platform: macOS Universal Binary (M-series + Intel), Windows x64, Linux x64

The markdown version is also at docs/implementation-plan.md. Want me to start scaffolding the Rust project?

Now let me generate a PDF for this plan too, and commit:

Now generate a nice PDF of the implementation plan:

No dude, we no longer do PDFs. That one was one off

Fair enough. The markdown is the real doc anyway — docs/implementation-plan.md. I'll ditch the .typ/.pdf for the plan. Want me to start scaffolding the Rust project?

summarize the implementation plan here

QuadraFuzz v1 — Implementation Plan Summary

Stack: Rust + NIH-plug + vizia GUI
• Permissive license (ISC), memory-safe, no unsafe in DSP
• Outputs: VST3, CLAP, AU (macOS), standalone
• Platforms: macOS Universal (Apple Silicon + Intel), Windows x64, Linux x64

Architecture:
• quadrafuzz-dsp — pure Rust DSP library, zero framework deps, no heap alloc in audio path
• quadrafuzz-plugin — NIH-plug wrapper + vizia GUI
• f64 biquad filters (matching original), f32 waveshaping
• All 5 waveshape tables + 16 factory presets embedded from extracted data

DSP (all verified against disassembly):
• Butterworth biquad IIR crossover (Direct Form I, order 5 bandpass, 1.15× band overlap, denormal flush < 1e-15)
• Table-lookup waveshaper (|x| × 254.0, linear interp, ±1.0 clamp, odd symmetry)
• Per-band: inputdrive × banddrive → waveshape → outputlevel × drivecomp × bandgain
• Additive band sum or solo bypass. No dry/wet.

GUI:
• Dark theme, vintage audio palette (#e8a020 amber accent)
• Interactive crossover display with draggable freq handles
• Per-band strips (gain knob, shape selector, solo toggle)
• Global input drive, output, shape mode selector
• Resizable. Optional retro mode using extracted bitmaps.

Phases:

1. DSP Core — 24h, weeks 1–2
2. Plugin Wrapper — 14h, week 3
3. GUI — 36h, weeks 3–5
4. Testing & Validation — 18h, week 6
5. Release + CI/CD — 12h, week 7
Total: 104 hours / 7 weeks at 15h/week

Post-v1.0 ideas:_ oversampling, per-band shape selection, spectrum analyzer, MIDI learn, user-loadable waveshape tables

Good. Implement it

Starting Phase 1 — DSP core. Will scaffold the Rust workspace and implement the full signal chain. This'll take a bit.

First, let me check if Rust is available and set up the workspace:

Good, Rust is ready. Let me spawn a sub-agent for the heavy lifting — implementing the full DSP core crate:

Sub-agent is building the DSP core crate. I'll check on it in a few minutes.

Oops, target/ got committed. Let me fix that.

Preset data is fixed and committed. Here's what was wrong and what I did:

Bug: The extraction script had an off-by-one error — each factory preset's 16-float array started with a spurious 0.0, shifting all values right by one position. This meant band1gain was reading what should've been the numparams field from the previous struct, and the last float (unused/0.0) was being dropped.

Fix (commit 6a3b242):

• Regenerated data/presets/presets.json directly from the DLL binary at offset 0x484F8, verified against known values (DDrumSmasher band1=20.0 ✓)
• Rewrote all 16 FACTORYDATA entries in presets.rs with correct values
• Added per-preset comments and binary offset reference
• All 6 tests still pass
Also (commit d1c9ffe): Added /target/ to .gitignore — it accidentally got committed with the DSP crate.

Where were we on the code review? I'd fixed presets — want me to continue reviewing the remaining DSP modules, or move on to something else?

Not sure what you want from me

Ah, my last message ended with a question ("want me to continue reviewing the remaining DSP modules, or move on to something else?") — that's what confused him. He said "implement it" and I've been doing that. No need to ask for direction.

what is the progress?

all done now?