Add a deswizzle/pupu compare to toml editor.

[Sebanisu]

Add Deswizzle/Pupu Compare to .toml Editor

Overview

We should create a comparison view in the .toml editor that shows the deswizzle results from:

• The original MIM data
• The generated TOML textures

The goal is to visualize and measure differences between the two outputs.

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🧩 Sub-Issues Breakdown

1. Extract and Modularize Deswizzle Logic

Goal: Make deswizzling reusable outside of map-sprite.

Tasks:

• Move existing deswizzle logic into a shared module (e.g. DeswizzleUtils or TextureDeswizzler).
• Separate file loading and GPU processing logic — make file loading optional or pluggable.
• Add an entry point to feed in already-loaded textures and custom output targets.
• Define a clean API like:

  DeswizzleResult DeswizzleTextures(const std::vector<Texture>& inputTextures, const DeswizzleOptions& options);

• Ensure output can be redirected (instead of always writing to the map-sprite’s output paths).

Acceptance Criteria:

• Can call DeswizzleTextures() from anywhere (not tied to map-sprite).
• Can provide custom texture sources and destination targets.
• Existing map-sprite still works using the new API.

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2. Integrate MIM + TOML Deswizzle into Editor

Goal: Run deswizzle on both MIM and TOML data using the new shared logic.

Tasks:

• Add functions to:
  • Load and deswizzle MIM texture set.
  • Deswizzle generated TOML texture set.
• Ensure both outputs share the same dimensions.
• Cache deswizzle results to avoid recomputation when switching views.

Acceptance Criteria:

• Both deswizzled versions are accessible to the editor.
• Deswizzle results match existing expected outputs when tested independently.

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3. Implement Texture Comparison Compute Shader

Goal: Compare deswizzled outputs pixel-by-pixel using OpenGL compute shaders.

Tasks:

• Write/modify compute shader to:
  • Read from two input textures.
  • Output a mask texture (white = different, black = same).
  • Count differing pixels and output the count to a buffer.
• Compute percent difference:

  percent = (diff_pixels / total_pixels) * 100.0f;

• Optionally: produce masked versions (MIM-masked, TOML-masked).

Acceptance Criteria:

• Shader correctly produces mask and difference metrics.
• Outputs usable by the UI layer.

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4. Build Comparison UI (Inline View)

Goal: Add comparison info to the .toml editor panel.

UI Elements:

• Table or pane with:
  • Left: MIM deswizzle
  • Right: TOML deswizzle
  • Center: numeric info (difference count, %)
• Reuse existing texture preview logic.

Acceptance Criteria:

• Can view both deswizzled images side by side.
• Pixel difference metrics update correctly.

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5. Add Optional Comparison Window

Goal: Provide a detailed view with mask visualization and toggles.

Features:

• Inputs: references to MIM texture, TOML texture, mask texture.
• Controls to:
  • Toggle between MIM / TOML / Mask.
  • Apply mask (show differing pixels only).
• Show checkerboard background for visibility (reuse existing draw window logic).

Acceptance Criteria:

• Separate window displays correctly.
• Toggles and mask application behave as expected.

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6. QA and Validation

Goal: Confirm correctness and consistency.

Tasks:

• Verify deswizzle output parity between MIM and TOML.
• Validate compute shader results with test textures.
• Ensure differences match expected pixel-level discrepancies.
• Confirm performance is acceptable (no unnecessary re-deswizzling).