feature(headless): Add GhostObjectManagerDummy for headless mode

[bobtista]

Summary

• Adds GhostObjectManagerDummy class that provides no-op implementations for headless mode
• Factory in W3DGameLogic returns dummy when m_headless is true
• Intentionally does NOT override crc/xfer/loadPostProcess to maintain save compatibility

Related

Split from #2139 per @xezon's suggestion to review each dummy class separately.

[greptile-apps]

Greptile Overview

Greptile Summary

Adds GhostObjectManagerDummy class for headless mode, providing no-op implementations for ghost object management which handles fog-of-war memory for objects. When running in headless mode, the factory in W3DGameLogic::createGhostObjectManager() now returns the dummy instead of the full W3DGhostObjectManager. This prevents unnecessary rendering operations since ghost objects are purely visual features.

The PR also removes the W3DDisplay::m_3DScene != nullptr check in W3DRenderObjectSnapshot::addToScene() that was previously added in #2133. This check is now redundant because the dummy manager returns nullptr from addGhostObject(), preventing any W3DGhostObject instances from being created in headless mode, which means addToScene() will never be called.

Key design decisions:

• Intentionally does NOT override crc/xfer/loadPostProcess to maintain save game compatibility
• Mirrors the same pattern used for other dummy classes in the headless implementation
• Changes are replicated identically across both Generals/ and GeneralsMD/ directories

Confidence Score: 5/5

• Safe to merge with no issues found
• The implementation follows established patterns for headless dummy classes, correctly preserves save compatibility by not overriding serialization methods, and the removal of the null check is logically sound since the dummy prevents ghost object creation entirely
• No files require special attention

Important Files Changed

Filename	Overview
Generals/Code/GameEngine/Include/GameLogic/GhostObject.h	Added GhostObjectManagerDummy class with no-op implementations for headless mode
Generals/Code/GameEngineDevice/Include/W3DDevice/GameLogic/W3DGameLogic.h	Modified factory to return GhostObjectManagerDummy when m_headless is true
Generals/Code/GameEngineDevice/Source/W3DDevice/GameLogic/W3DGhostObject.cpp	Removed m_3DScene null check in addToScene(), now redundant with dummy implementation
GeneralsMD/Code/GameEngine/Include/GameLogic/GhostObject.h	Added GhostObjectManagerDummy class with no-op implementations for headless mode
GeneralsMD/Code/GameEngineDevice/Include/W3DDevice/GameLogic/W3DGameLogic.h	Modified factory to return GhostObjectManagerDummy when m_headless is true
GeneralsMD/Code/GameEngineDevice/Source/W3DDevice/GameLogic/W3DGhostObject.cpp	Removed m_3DScene null check in addToScene(), now redundant with dummy implementation

Sequence Diagram

sequenceDiagram
    participant W3DGameLogic
    participant GhostObjectManagerDummy
    participant PartitionManager
    participant W3DGhostObject

    Note over W3DGameLogic: createGhostObjectManager()
    alt headless mode
        W3DGameLogic->>GhostObjectManagerDummy: NEW GhostObjectManagerDummy
        GhostObjectManagerDummy-->>W3DGameLogic: return dummy instance
    else normal mode
        W3DGameLogic->>W3DGhostObject: NEW W3DGhostObjectManager
        W3DGhostObject-->>W3DGameLogic: return real instance
    end

    Note over PartitionManager: Object enters fog
    alt headless mode with dummy
        PartitionManager->>GhostObjectManagerDummy: addGhostObject(object, pd)
        GhostObjectManagerDummy-->>PartitionManager: return nullptr (no-op)
        Note over PartitionManager: No ghost object created<br/>No scene interaction needed
    else normal mode
        PartitionManager->>W3DGhostObject: addGhostObject(object, pd)
        W3DGhostObject->>W3DGhostObject: Create W3DGhostObject
        W3DGhostObject->>W3DGhostObject: addToScene() - adds to m_3DScene
        W3DGhostObject-->>PartitionManager: return ghost object
    end

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[greptile-apps]

_{2 files reviewed, 2 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

Unnecessary static_cast<GhostObjectManager*> since GhostObjectManagerDummy already inherits from GhostObjectManager

Suggested change

	virtual GhostObjectManager *createGhostObjectManager(void) { return TheGlobalData->m_headless ? static_cast<GhostObjectManager*>(NEW GhostObjectManagerDummy) : NEW W3DGhostObjectManager; }
	virtual GhostObjectManager *createGhostObjectManager(void) { return TheGlobalData->m_headless ? NEW GhostObjectManagerDummy : NEW W3DGhostObjectManager; }

Prompt To Fix With AI

This is a comment left during a code review.
Path: Generals/Code/GameEngineDevice/Include/W3DDevice/GameLogic/W3DGameLogic.h
Line: 64:64

Comment:
Unnecessary `static_cast<GhostObjectManager*>` since `GhostObjectManagerDummy` already inherits from `GhostObjectManager`

```suggestion
	virtual GhostObjectManager *createGhostObjectManager(void) { return TheGlobalData->m_headless ? NEW GhostObjectManagerDummy : NEW W3DGhostObjectManager; }
```

How can I resolve this? If you propose a fix, please make it concise.

[greptile-apps]

Unnecessary static_cast<GhostObjectManager*> since GhostObjectManagerDummy already inherits from GhostObjectManager

Suggested change

	virtual GhostObjectManager *createGhostObjectManager(void) { return TheGlobalData->m_headless ? static_cast<GhostObjectManager*>(NEW GhostObjectManagerDummy) : NEW W3DGhostObjectManager; }
	virtual GhostObjectManager *createGhostObjectManager(void) { return TheGlobalData->m_headless ? NEW GhostObjectManagerDummy : NEW W3DGhostObjectManager; }

Prompt To Fix With AI

This is a comment left during a code review.
Path: GeneralsMD/Code/GameEngineDevice/Include/W3DDevice/GameLogic/W3DGameLogic.h
Line: 64:64

Comment:
Unnecessary `static_cast<GhostObjectManager*>` since `GhostObjectManagerDummy` already inherits from `GhostObjectManager`

```suggestion
	virtual GhostObjectManager *createGhostObjectManager(void) { return TheGlobalData->m_headless ? NEW GhostObjectManagerDummy : NEW W3DGhostObjectManager; }
```

How can I resolve this? If you propose a fix, please make it concise.

[bobtista]

I think this is required for VC6, it failed to build without it