feat(option): Add user option to enable or disable Right Mouse Scroll with Alternate Mouse

[xezon]

• Follow up for unify(translator): Merge message translators from Zero Hour #2794

This change adds a user option to enable or disable Right Mouse Scroll with Alternate Mouse. It can be toggled with UseRightMouseScrollWithAlternateMouse=yes/no in the Options.ini

The reason for this option is that before merge #2794 the RMB scroll was disabled in Generals, but enabled in Zero Hour. It is now default disabled in Generals and default enabled in Zero Hour, but both games can toggle it. This avoids potential irritations for legacy Generals players with Alternate Mouse setup.

TODO

• Replicate in Generals

[greptile-apps]

Greptile Summary

This PR adds a UseRightMouseScrollWithAlternateMouse user option (ini-only for now) that controls whether RMB scrolling is active when Alternate Mouse mode is enabled, defaulting to disabled in Generals and enabled in Zero Hour to preserve legacy behavior.

• Core/OptionPreferences: new getRightMouseScrollWithAlternateMouseEnabled() getter reads the preference and falls back to the GlobalData default, but the field it references (m_useRightMouseScrollWithAlternateMouse) is absent from Generals/Code/GameEngine/Include/Common/GlobalData.h, breaking the Generals build.
• GeneralsMD/GlobalData: field is declared and initialized correctly for Zero Hour; however the #if RTS_GENERALS block in the GeneralsMD constructor is dead code (that macro is never set in a ZH build), so the Generals-specific default path is unreachable here.
• LookAtXlat / OptionsMenu: logic and round-trip save are sound; the missing UI checkbox is acknowledged via @todo.

Confidence Score: 2/5

Not safe to merge as-is — the Generals build will not compile because the new GlobalData field is missing from the vanilla Generals header and the corresponding source file is also not updated.

The shared OptionPreferences.cpp getter directly accesses TheGlobalData->m_useRightMouseScrollWithAlternateMouse, but Generals/Code/GameEngine/Include/Common/GlobalData.h has no such member. Because the Generals g_gameengine target compiles Core sources against the Generals headers, this is a hard build error for the Generals executable. The Zero Hour side of the change is correct, but the missing Generals-side companion work (header field, constructor init, parseGameDataDefinition assignment) must be added before this can land.

Generals/Code/GameEngine/Include/Common/GlobalData.h and Generals/Code/GameEngine/Source/Common/GlobalData.cpp — both need the new field and its initialization/loading, which were applied to GeneralsMD but not to the Generals equivalents.

Important Files Changed

Filename	Overview
Core/GameEngine/Include/Common/OptionPreferences.h	Adds getRightMouseScrollWithAlternateMouseEnabled() const declaration, consistent with existing getter style.
Core/GameEngine/Source/Common/OptionPreferences.cpp	New getter accesses TheGlobalData->m_useRightMouseScrollWithAlternateMouse, but this field is missing from Generals/GlobalData.h, causing a build failure for the Generals target.
GeneralsMD/Code/GameEngine/Include/Common/GlobalData.h	Adds m_useRightMouseScrollWithAlternateMouse field to Zero Hour's GlobalData struct correctly.
GeneralsMD/Code/GameEngine/Source/Common/GlobalData.cpp	Initializes and loads the new preference; contains a dead #if RTS_GENERALS branch (never true in ZH builds) and a newly added comment referencing a 2003 date.
GeneralsMD/Code/GameEngine/Source/GameClient/GUI/GUICallbacks/Menus/OptionsMenu.cpp	Round-trips the preference value on save (no UI control yet, acknowledged via @todo). This is intentional but the setting is effectively read-only from the UI until a checkbox is added.
GeneralsMD/Code/GameEngine/Source/GameClient/MessageStream/LookAtXlat.cpp	Correctly gates RMB scroll on the new m_useRightMouseScrollWithAlternateMouse flag using clear boolean logic.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["MSG_RAW_MOUSE_RIGHT_BUTTON_DOWN"] --> B{"m_useAlternateMouse?"}
    B -- No --> C["userWantsRMBScroll = true"]
    B -- Yes --> D{"m_useRightMouseScrollWithAlternateMouse?"}
    D -- Yes --> C
    D -- No --> E["userWantsRMBScroll = false"]
    C --> F{"isSelecting or isScrolling?"}
    F -- No --> G["setScrolling(SCROLL_RMB)"]
    F -- Yes --> H["No action"]
    E --> H

    subgraph Init["Startup: parseGameDataDefinition"]
        I["OptionPreferences::getRightMouseScrollWithAlternateMouseEnabled()"]
        I --> J{"Key in Options.ini?"}
        J -- No --> K["Fall back to GlobalData default\n(Generals=false, ZH=true)"]
        J -- Yes --> L["Parse yes/no"]
        L --> M["Set TheWritableGlobalData->m_useRightMouseScrollWithAlternateMouse"]
        K --> M
    end

Loading

Prompt To Fix All With AI

Fix the following 3 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 3
Core/GameEngine/Source/Common/OptionPreferences.cpp:206-216
**Missing `m_useRightMouseScrollWithAlternateMouse` in Generals GlobalData.h**

`getRightMouseScrollWithAlternateMouseEnabled()` accesses `TheGlobalData->m_useRightMouseScrollWithAlternateMouse`, but the field was only added to `GeneralsMD/Code/GameEngine/Include/Common/GlobalData.h`. The Generals build compiles this `Core` file against `Generals/Code/GameEngine/Include/Common/GlobalData.h`, which does not declare this member — causing a hard compilation failure for the Generals target. `Generals/Code/GameEngine/Include/Common/GlobalData.h` needs the new field, and `Generals/Code/GameEngine/Source/Common/GlobalData.cpp` must both initialize it in the constructor and apply the user preference in `parseGameDataDefinition`.

### Issue 2 of 3
GeneralsMD/Code/GameEngine/Source/Common/GlobalData.cpp:1056-1062
The `#if RTS_GENERALS` branch is dead code in this file — `RTS_GENERALS` is defined only for the vanilla Generals build, never for the GeneralsMD (Zero Hour) build. Only the `#else` branch will ever execute here, so the conditional and its comment add noise without effect. The Generals-specific default belongs in `Generals/Code/GameEngine/Source/Common/GlobalData.cpp`.

```suggestion
	m_useAlternateMouse = FALSE;
	m_useRightMouseScrollWithAlternateMouse = TRUE;
```

### Issue 3 of 3
GeneralsMD/Code/GameEngine/Source/Common/GlobalData.cpp:1058-1059
**Newly added comment references a 2003 date**

The comment `// disable mouse scrolling in alternate mouse mode, per Harvard 7/15/03` is newly introduced in this PR and cites a date from 2003. Per the project's annotation convention, newly created comments should not reference years prior to the current year (2026).

_{Reviews (1): Last reviewed commit: "feat(option): Add user option to enable ..." | Re-trigger Greptile}

[Skyaero42]

return stricmp(it->second.str(), "yes") == 0;

if statement not needed.

[xezon]

I agree we should simplify the code here, but currently this is consistent with how the other functions in this class are written.

[Skyaero42]

Is this related to this PR?

[xezon]

No. I saw the nearby mouse input vars are uninitialized so I added init values for them.

Do you need me to remove that?