Codestin Search App

alexbevi · 2026-08-17T11:41:08Z

This PR adds an initial, Ghidra-backed implementation of the DOS game Ripper.

As with the previous re-implementation of Harvester, this PR uses Ghidra and Codex (notes available in this gist). AI-GUIDELINES.md was followed, and to make validation easier, commit messages include the binary disassembly notes and function addresses as references.

The original work was done against the v1.0 game, but I eventually introduced v1.05 functionality such as interaction subtitles. I documented the IAVF format in greater detail in this blog post, and will look to add more content over time.

Shared code changes

Only two shared runtime areas are changed, so I wanted to call them out directly.

Area	Reason
`IMAGE` IFF decoder (`8d706d7dd82`, `a42c63d6c5f`)	Ripper PBM rows use an even-byte stored stride when their logical width is odd. The shared decoder gains a protected override point, while an engine-local subclass skips the padding. Other engines retain the existing PBM behavior.
GUI list scrolling (`4a93237885f`)	`ListWidget::scrollTo()` clamps the logical row before calculating its fluid-scroll position. This prevents a remembered save-chooser position from clipping or moving the first entries when every slot fits onscreen.
Tests (`6d6f5d76fef`)	`test/module.mk` includes the Ripper test suites and static engine library when Ripper is configured as a static plugin.

No common media, audio, event, savefile or serializer code is modified.

Run with ./scummvm -d 3 --debugflags=general,resources,scripts,scene,input,audio,cursor,video,dialogue,wac,saveload,milestones,puzzles,cyber,combat ripper for full debug output.

Screenshots

References: - RIPPER.LE: RunTubeSwitchScene at 0x25e18 - RIPPER.LE: RunFrontEndActionMenu at 0x18b3a - RIPPER.LE: RunUnlockGatedSelectionMenu at 0x360ae - RIPPER.LE: ExecuteUnlockSelectionChoice at 0x364be Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunKaDialogueScene at 0x2aef5 Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunTubeSwitchScene at 0x25e18 - RIPPER.LE: RunKaDialogueScene at 0x2aef5 - RIPPER.LE: RunCainDialogueScene at 0x2c160 - RIPPER.LE: RunCrystalPiecePlacementPuzzleScene at 0x2710c - RIPPER.LE: RunRolodexSequencePuzzleScene at 0x280ae - RIPPER.LE: RunShockLeverPuzzleScene at 0x3affb Assisted-by: Codex:gpt-5

The powered switch loop must reuse one Smacker decoder because later frames depend on its delta-coded surface and palette. References: - RIPPER.LE: RunTubeSwitchScene at 0x25e18 - RIPPER.LE: retained-decoder seek path at 0x263ae Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunCombatEncounterScene at 0x31436 - RIPPER.LE: LoadCombatEncounterResourceSet at 0x34d6e - RIPPER.LE: LoadPresentationFrameRegionTable at 0x35615 - RIPPER.LE: LoadPresentationFrameAudioCueMap at 0x3574a Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunGcCshFourChoiceSequencePuzzleScene at 0x38871 - RIPPER.LE: DispatchSceneEntryAction at 0x36892 - RIPPER.LE: PreparePacketizedMediaPlaybackBranchSetup at 0x5b237 Assisted-by: Codex:gpt-5

Player depletion follows the Escape cleanup path and must not set the completion flag. References: - RIPPER.LE: RunCombatEncounterScene at 0x31436 Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunGcCshFourChoiceSequencePuzzleScene at 0x38871 Assisted-by: Codex:gpt-5

The cursor frame and palette must be reinstalled after puzzle media even when the requested cursor row is unchanged. References: - RIPPER.LE: RunGcCshFourChoiceSequencePuzzleScene at 0x3868b - RIPPER.LE: cursor reinstallation paths at 0x38986 through 0x389a2 and 0x38e98 through 0x38ea1 Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunGcCshFourChoiceSequencePuzzleScene at 0x38871 - RIPPER.LE: ServiceUiControlStateSelection at 0x4a912 Assisted-by: Codex:gpt-5

Save version 4 adds the toolbar mask. Older supported saves restore the original full mask. References: - RIPPER.LE: DispatchSceneEntryAction at 0x36892 - RIPPER.LE: PollInteractionAndResolveSelection at 0x13c8d Assisted-by: Codex:gpt-5

A scene action unlocks the new item and clears its consumed partner before opening the chooser. The toolbar opens the same chooser without mutating inventory. References: - RIPPER.LE: DispatchSceneEntryAction at 0x36892 - RIPPER.LE: RunUnlockGatedSelectionMenu at 0x360ae - RIPPER.LE: ExecuteUnlockSelectionChoice at 0x364be Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunUnlockGatedSelectionMenu at 0x360ae - RIPPER.LE: ExecuteUnlockSelectionChoice at 0x364be - RIPPER.LE: InitializeSharedPresentationTemplates at 0x1196f Assisted-by: Codex:gpt-5

References: - RIPPER.LE: DrawPromptChooserTemplateLabelCallback at 0x16d0f Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunTableGateLeverPuzzleScene at 0x3912a Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunClockPuzzleScene at 0x374c5 - RIPPER.LE: PlayClockSmackerOverlayAnimation at 0x38316 - RIPPER.LE: DispatchSceneEntryAction at 0x36892 Assisted-by: Codex:gpt-5

CLOCK_TMP.MCG is one custom bitmap, not a bitmap-set container. References: - RIPPER.LE: RunClockPuzzleScene at 0x374c5 - RIPPER.LE: DecodeCustomBitmapAsset at 0x53fdf Assisted-by: Codex:gpt-5

Assisted-by: Codex:gpt-5

References: - RIPPER.LE: DecodeCustomBitmapAsset at 0x53f60 Assisted-by: Codex:gpt-5

Assisted-by: Codex:gpt-5

The first registered overlapping control wins the hit test. References: - RIPPER.LE: FindUiControlStateAtPoint at 0x4aae8 Assisted-by: Codex:gpt-5

Save data retains the existing selected and first-visible fields. The model validates them before rebuilding layout. Assisted-by: Codex:gpt-5

The index accelerates exact lookup without changing directory order used by member sizing and prefix enumeration. References: - RIPPER.LE: OpenIndexedContainerEntryReadOnly at 0x55a4c - RIPPER.LE: LoadAssetLibraryDirectoryFromOpenHandle at 0x6ad80 Assisted-by: Codex:gpt-5

Assisted-by: Codex:gpt-5

References: - RIPPER.LE: CreateSceneRuntime at 0x12be7 Assisted-by: Codex:gpt-5

References: - RIPPER.LE: RunSceneCallbackCommandStream at 0x14080 - RIPPER.LE: DispatchSceneEntryAction at 0x36892 Assisted-by: Codex:gpt-5