cwilliams5/review-shaders-open

Enter planning mode. Deep-audit HLSL pixel shaders in src/shaders/ for GPU performance waste — redundant math, avoidable transcendentals, suboptimal patterns. Use maximum parallelism — spawn explore agents for independent shader groups. Every optimization must be visually identical to the original.

Context Alt-Tabby renders background shaders at 120-240fps via D3D11 pixel shaders compiled from HLSL to DXBC. These shaders are converted from Shadertoy GLSL — many carry unoptimized patterns from their original authors or from mechanical GLSL→HLSL conversion. At 240fps on a 1440p display, every pixel shader instruction runs ~885M times/second (3840×1600×240÷2 assuming half the overlay is visible). Even saving one ALU instruction matters.

Scope: All src/shaders/**/*.hlsl files (including mouse/ and selection/ subdirs). Includes both pixel shader (PSMain) and compute shader (CSMain) logic — mouse shaders may contain both in a single .hlsl file. Does NOT cover:

The D3D11 host-side code in d2d_shader.ahk (use review-paint for the D2D pipeline) The AHK-side effect chain or compositing (use review-paint) Shader compilation or bundling tooling Cardinal rule: Every optimization must produce visually identical output. These are aesthetic shaders — if you can't prove the math is equivalent, don't suggest the change. "Close enough" is not acceptable.

What to Look For Any other detected optimizations. In the past I've directed you - this time, lets see what you do on your own.

Files to Audit All .hlsl files in src/shaders/ and subdirectories (mouse/, selection/). There are 150+ shaders. Organize the audit by pattern, not by individual file — many shaders share the same noise functions, FBM loops, and rotation patterns.

Use the .glsl source as reference when verifying visual equivalence — it shows the original author intent.

Explore Strategy Do not filter. A single saved transcendental ×885M pixels/sec = real watts and real frame time. List everything.

Validation Prove equivalence: For every suggested change, show the mathematical equivalence. If equivalence requires assumptions (e.g., "x is non-negative"), state the assumption and verify it holds in context.

Check the GLSL original: If the HLSL already differs from the GLSL in a way that suggests intentional optimization during conversion, don't flag it again.

Don't break visual output: If unsure whether a simplification is visually identical, err on the side of not suggesting it. Mark uncertain cases as "needs visual verification."

Respect author intent: Some "inefficiencies" are intentional artistic choices (e.g., a specific pow curve for color grading). Don't optimize these away.

Plan Format Section 1 — Transcendental Optimizations:

Pattern Affected Shaders Per-Pixel Cost Saved Complexity Fix Section 2 — Loop Optimizations:

Pattern Affected Shaders Per-Pixel Cost Saved Complexity Fix Section 3 — Algebraic Simplifications:

Pattern Affected Shaders Per-Pixel Cost Saved Complexity Fix Section 4 — Conversion Artifacts:

Pattern Affected Shaders Per-Pixel Cost Saved Complexity Fix Order within each section by total impact (per-pixel savings × number of affected shaders, highest first).

Ignore any existing plans — create a fresh one.

MANDATORY: Post-Implementation Verification

After implementing any shader changes, you MUST:

1. Run the full --live test suite — powershell -File tests/test.ps1 --live. This compiles the exe (which compiles HLSL→DXBC) and validates everything end-to-end.
2. Check git status for changed .bin files in resources/shaders/. HLSL source changes produce new compiled DXBC binaries — these MUST be committed alongside the .hlsl changes.
3. Do not ship until both the test suite passes and all compiled bins are staged.

Shader changes without compiled bins are broken — the compiled exe embeds the .bin files, not the .hlsl source.