yaze/docs/internal/agents/archive/gemini-sessions/gemini-v040-session.md

Gemini 3 Pro - v0.4.0 Development Session

Context

You are working on YAZE (Yet Another Zelda3 Editor), a C++23 cross-platform ROM editor for The Legend of Zelda: A Link to the Past.

Current Situation:

• v0.3.9: CI/CD hotfix running (another agent handling - DO NOT TOUCH)
• v0.4.0: Your focus - "Editor Stability & OOS Support"
• Goal: Unblock Oracle of Secrets (OOS) ROM hack development

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Quick Start

# Use dedicated build directory (DO NOT use build/ or build_agent/)
cmake --preset mac-dbg -B build_gemini
cmake --build build_gemini -j8 --target yaze

# Run stable tests
ctest --test-dir build_gemini -L stable -j4 --output-on-failure

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Completed Work

Priority 2: Message Editor - Expanded BIN Export [COMPLETE]

Completed by Gemini 3 Pro:

1. JSON Export Implementation (message_data.h/cc):

   • Added SerializeMessagesToJson() - Converts MessageData vector to JSON array
   • Added ExportMessagesToJson() - Writes JSON file with error handling
   • Uses nlohmann/json library with 2-space pretty printing

2. File Dialog Integration (message_editor.cc:317-376):

   • "Load Expanded Message" - Opens file dialog to load BIN
   • "Save Expanded Messages" - Saves to remembered path
   • "Save As..." - Prompts for new path
   • "Export to JSON" - JSON export with file dialog

3. Path Persistence:

   • expanded_message_path_ member stores last used path
   • Reuses path for subsequent saves

4. SaveExpandedMessages() Implementation (message_editor.cc:521-571):

   • Uses expanded_message_bin_ member for ROM-like storage
   • Handles buffer expansion for new messages
   • Writes terminator byte (0xFF) after data

Priority 1: Dungeon Editor - SaveDungeon() [IN PROGRESS]

Completed by Gemini 3 Pro:

1. SaveDungeon() Implementation (dungeon_editor_system.cc:44-59):

   • No longer a stub! Loops through all 296 rooms
   • Calls SaveRoomData() for each room
   • Tracks dirty state and last save time

2. SaveObjects() Implementation (room.cc:873-925):

   • Properly calculates available space via CalculateRoomSize()
   • Validates encoded size fits before writing
   • Returns OutOfRangeError if data too large

3. SaveSprites() Implementation (room.cc:927-999):

   • Calculates sprite space from pointer table
   • Handles sortsprites byte
   • Returns OutOfRangeError if data too large

4. New Tests (test/unit/zelda3/dungeon/dungeon_save_test.cc):

   • SaveObjects_FitsInSpace - verifies normal save works
   • SaveObjects_TooLarge - verifies overflow detection
   • SaveSprites_FitsInSpace - verifies normal save works
   • SaveSprites_TooLarge - verifies overflow detection

Tests Pass:

./build_gemini/bin/Debug/yaze_test_stable --gtest_filter="*DungeonSave*"
# [  PASSED  ] 4 tests.

---

Testing Instructions

Build and Run Tests

# Build test target (uses existing build_gemini)
cmake --build build_gemini --target yaze_test_stable -j8

# Run ALL stable tests
./build_gemini/bin/Debug/yaze_test_stable

# Run specific test pattern
./build_gemini/bin/Debug/yaze_test_stable --gtest_filter="*DungeonSave*"

# Run dungeon-related tests
./build_gemini/bin/Debug/yaze_test_stable --gtest_filter="*Dungeon*"

# Run with verbose output
./build_gemini/bin/Debug/yaze_test_stable --gtest_filter="*YourTest*" --gtest_print_time=1

Known Test Issues (Pre-existing)

FAILING: RoomObjectEncodingTest.DetermineObjectTypeType2

• Location: test/unit/zelda3/dungeon/room_object_encoding_test.cc:29-31
• Issue: DetermineObjectType() returns 1 instead of 2 for bytes 0xFC, 0xFD, 0xFF
• Status: Pre-existing failure, NOT caused by your changes
• Action: Ignore unless you're specifically working on object type detection

Test File Locations

Test Type	Location	Filter Pattern
Dungeon Save	test/unit/zelda3/dungeon/dungeon_save_test.cc	*DungeonSave*
Room Encoding	test/unit/zelda3/dungeon/room_object_encoding_test.cc	*RoomObjectEncoding*
Room Manipulation	test/unit/zelda3/dungeon/room_manipulation_test.cc	*RoomManipulation*
Dungeon Integration	test/integration/dungeon_editor_test.cc	*DungeonEditorIntegration*
Overworld	test/unit/zelda3/overworld_test.cc	*Overworld*

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Your Priorities (Pick One)

Priority 1: Dungeon Editor - Save Infrastructure [COMPLETE] ✅

Completed by Gemini 3 Pro:

1. SaveRoomData() Implementation (dungeon_editor_system.cc:914-973):

   • ✅ Detects if room is currently being edited in UI
   • ✅ Uses editor's in-memory Room object (contains unsaved changes)
   • ✅ Syncs sprites from DungeonEditorSystem to Room before saving
   • ✅ Selectively saves objects only for current room (optimization)

2. UI Integration (dungeon_editor_v2.cc:244-291):

   • ✅ Save() method calls SaveDungeon() correctly
   • ✅ Palette saving via PaletteManager
   • ✅ Room objects saved via Room::SaveObjects()
   • ✅ Sprites saved via DungeonEditorSystem::SaveRoom()

3. Edge Cases Verified:

   • ✅ Current room with unsaved changes
   • ✅ Non-current rooms (sprite-only save)
   • ✅ Multiple rooms open in tabs
   • ✅ Empty sprite lists

Audit Report: zscow_audit_report.md (artifact)

Minor Improvements Recommended:

• Add integration tests for DungeonEditorSystem save flow
• Remove redundant SaveObjects() call in DungeonEditorV2::Save()
• Document stub methods

Test your changes:

./build_gemini/bin/Debug/yaze_test_stable --gtest_filter="*DungeonSave*:*RoomManipulation*"

---

Priority 3: ZSCOW Audit [COMPLETE] ✅

Completed by Gemini 3 Pro:

1. Version Detection - VERIFIED ✅

Implementation: overworld_version_helper.h:51-71

ASM Byte	Version	Status
0xFF	Vanilla	✅ Correct
0x00	Vanilla	✅ CORRECT - Expanded ROMs are zero-filled
0x01	v1	✅ Verified
0x02	v2	⚠️ Not tested (no v2 ROM available)
0x03+	v3	✅ Verified

Task 1: Version 0x00 Edge Case - RESOLVED ✅

• Answer: Treating 0x00 as vanilla is CORRECT
• Rationale: When vanilla ROM is expanded to 2MB, new space is zero-filled
• Address: 0x140145 is in expanded space (beyond 1MB)
• Tests Added: 5 comprehensive tests in overworld_version_helper_test.cc
• Bounds Check Added: Prevents crashes on small ROMs

Task 2: Death Mountain GFX TODO - DOCUMENTED ⚠️

Location: overworld_map.cc:595-602

• Current logic: Checks parent ranges 0x03-0x07, 0x0B-0x0E (LW), 0x43-0x47, 0x4B-0x4E (DW)
• Recommended: Only check 0x03, 0x05, 0x07 (LW) and 0x43, 0x45, 0x47 (DW)
• Rationale: Matches ZScream 3.0.4+ behavior, handles non-large DM areas correctly
• Impact: Low risk improvement
• Status: Documented in audit report, not implemented yet

Task 3: ConfigureMultiAreaMap - FULLY VERIFIED ✅

Location: overworld.cc:267-422

• ✅ Vanilla ROM: Correctly rejects Wide/Tall areas
• ✅ v1/v2 ROM: Same as vanilla (no area enum support)
• ✅ v3 ROM: All 4 sizes work (Small, Large, Wide, Tall)
• ✅ Sibling cleanup: Properly resets all quadrants when shrinking Large→Small
• ✅ Edge maps: Boundary conditions handled safely

Task 4: Special World Hardcoded Cases - VERIFIED ✅

Location: overworld_map.cc:202-293

• ✅ Triforce room (0x88, 0x93): Special graphics 0x51, palette 0x00
• ✅ Master Sword area (0x80): Special GFX group
• ✅ Zora's Domain (0x81, 0x82, 0x89, 0x8A): Sprite GFX 0x0E
• ✅ Version-aware logic for v3 vs vanilla/v2

Audit Report: zscow_audit_report.md (artifact)

Test Results:

./build_gemini/bin/Debug/yaze_test_stable --gtest_filter="OverworldVersionHelperTest*"
# [  PASSED  ] 5 tests.

Overall Assessment: ZSCOW implementation is production-ready with one low-priority enhancement (Death Mountain GFX logic).

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Priority 4: Agent Inspection - Wire Real Data [MEDIUM] - DETAILED

Problem: CLI inspection commands return stub output. Helper functions exist but aren't connected.

Overworld Command Handlers (src/cli/handlers/game/overworld.cc)

Line	Handler	Status	Helper to Use
33	OverworldGetTileCommandHandler	TODO	Manual ROM read
84	OverworldSetTileCommandHandler	TODO	Manual ROM write
162	OverworldFindTileCommandHandler	TODO	FindTileMatches()
325	OverworldDescribeMapCommandHandler	TODO	BuildMapSummary()
508	OverworldListWarpsCommandHandler	TODO	CollectWarpEntries()
721	OverworldSelectRectCommandHandler	TODO	N/A (GUI)
759	OverworldScrollToCommandHandler	TODO	N/A (GUI)
794	OverworldSetZoomCommandHandler	TODO	N/A (GUI)
822	OverworldGetVisibleRegionCommandHandler	TODO	N/A (GUI)

Dungeon Command Handlers (src/cli/handlers/game/dungeon_commands.cc)

Line	Handler	Status
36	Sprite listing	TODO - need Room::sprites()
158	Object listing	TODO - need Room::objects()
195	Tile data	TODO - need Room::floor1()/floor2()
237	Property setting	TODO - need Room::set_*() methods

Available Helper Functions (overworld_inspect.h)

These are fully implemented and ready to use:

// Build complete map metadata summary
absl::StatusOr<MapSummary> BuildMapSummary(zelda3::Overworld& overworld, int map_id);

// Find all warps matching query (entrances, exits, holes)
absl::StatusOr<std::vector<WarpEntry>> CollectWarpEntries(
    const zelda3::Overworld& overworld, const WarpQuery& query);

// Find all occurrences of a tile16 ID
absl::StatusOr<std::vector<TileMatch>> FindTileMatches(
    zelda3::Overworld& overworld, uint16_t tile_id, const TileSearchOptions& options);

// Get sprites on overworld maps
absl::StatusOr<std::vector<OverworldSprite>> CollectOverworldSprites(
    const zelda3::Overworld& overworld, const SpriteQuery& query);

// Get entrance details by ID
absl::StatusOr<EntranceDetails> GetEntranceDetails(
    const zelda3::Overworld& overworld, uint8_t entrance_id);

// Analyze how often a tile is used
absl::StatusOr<TileStatistics> AnalyzeTileUsage(
    zelda3::Overworld& overworld, uint16_t tile_id, const TileSearchOptions& options);

Example Fix Pattern

// BEFORE (broken):
absl::Status OverworldFindTileCommandHandler::Execute(
    CommandContext& context, std::ostream& output) {
  output << "Placeholder: would find tile...";  // STUB!
  return absl::OkStatus();
}

// AFTER (working):
absl::Status OverworldFindTileCommandHandler::Execute(
    CommandContext& context, std::ostream& output) {
  auto tile_id_str = context.GetArgument("tile_id");
  ASSIGN_OR_RETURN(auto tile_id, ParseHexOrDecimal(tile_id_str));

  TileSearchOptions options;
  if (auto world = context.GetOptionalArgument("world")) {
    ASSIGN_OR_RETURN(options.world, ParseWorldSpecifier(*world));
  }

  ASSIGN_OR_RETURN(auto matches,
      overworld::FindTileMatches(context.overworld(), tile_id, options));

  output << "Found " << matches.size() << " occurrences:\n";
  for (const auto& match : matches) {
    output << absl::StrFormat("  Map %d (%s): (%d, %d)\n",
        match.map_id, WorldName(match.world), match.local_x, match.local_y);
  }
  return absl::OkStatus();
}

Priority Order

1. OverworldDescribeMapCommandHandler - Most useful for agents
2. OverworldFindTileCommandHandler - Common query
3. OverworldListWarpsCommandHandler - Needed for navigation
4. Dungeon sprite/object listing - For dungeon editing support

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DO NOT TOUCH

• .github/workflows/ - CI/CD hotfix in progress
• build/, build_agent/, build_test/ - User's build directories
• src/util/crash_handler.cc - Being patched for Windows

---

Code Style

• Use absl::Status and absl::StatusOr<T> for error handling
• Macros: RETURN_IF_ERROR(), ASSIGN_OR_RETURN()
• Format: cmake --build build_gemini --target format
• Follow Google C++ Style Guide

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Reference Documentation

• CLAUDE.md - Project conventions and patterns
• Roadmap: docs/internal/roadmaps/2025-11-23-refined-roadmap.md
• Message Editor Plans: docs/internal/plans/message_editor_implementation_roadmap.md
• Test Guide: docs/public/build/quick-reference.md

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Recommended Approach

1. Pick ONE priority to focus on
2. Read the relevant files before making changes
3. Run tests frequently (ctest --test-dir build_gemini -L stable)
4. Commit with clear messages following conventional commits (fix:, feat:)
5. Don't touch CI/CD - that's being handled separately

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Current State of Uncommitted Work

The working tree has changes you should be aware of:

• tile16_editor.cc - Texture queueing improvements
• entity.cc/h - Sprite movement fixes
• overworld_editor.cc - Entity rendering
• overworld_map.cc - Map rendering
• object_drawer.cc/h - Dungeon objects

Review these before making overlapping changes.

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Success Criteria

When you're done, one of these should be true:

• Dungeon save actually persists changes to ROM COMPLETE ✅
• Message editor can export expanded BIN files COMPLETE ✅
• ZSCOW loads correctly for vanilla + v1/v2/v3 ROMs COMPLETE ✅
• Agent inspection returns real data

Good luck!