bugfix(supply): Implement proportional supply bonus scaling

[tintinhamans]

• Added a new getMaxBoxes() method to SupplyTruckAIInterface and implemented it in both SupplyTruckAIUpdate and WorkerAIUpdate to expose the configured maximum box capacity.

• Updated SupplyCenterDockUpdate::action to snapshot the box count before unloading and scale the upgrade bonus proportionally to the delivered cargo.

Closes #132

[greptile-apps]

Greptile Summary

This PR introduces proportional supply-upgrade bonus scaling: rather than always granting a flat UpgradedSupplyBoost when a truck docks, the bonus is now scaled by deliveredBoxes / maxBoxes so that a partially-loaded truck receives only a proportional reward. The change is gated behind #if !RETAIL_COMPATIBLE_CRC to preserve CRC parity for multiplayer/replay builds. The implementation is clean and well-scoped.

Key changes:

• getMaxBoxes() added as a pure virtual to SupplyTruckAIInterface and implemented inline in both SupplyTruckAIUpdate (from m_maxBoxesData) and WorkerAIUpdate (from its own module data). ChinookAIUpdate inherits the implementation correctly from SupplyTruckAIUpdate.
• A new getUpgradedSupplyBoostValue() static helper in SupplyCenterDockUpdate.cpp snapshots the box count before loseOneBox() is called, which correctly captures the delivered quantity and prevents empty trucks from receiving any bonus.
• The maxBoxes > 0 guard in the non-retail path prevents a division-by-zero crash for units whose MaxBoxes INI field is unset, returning 0 in that case. Note that this is a silent behaviour change for any hypothetical unit with UpgradedSupplyBoost > 0 but no MaxBoxes configured — the team has already accepted this trade-off in prior review discussion.

Confidence Score: 4/5

• Safe to merge; the fix is logically correct and all previously raised concerns have been addressed or accepted.
• All concrete implementors of SupplyTruckAIInterface (SupplyTruckAIUpdate, WorkerAIUpdate, ChinookAIUpdate) correctly satisfy the new getMaxBoxes() pure virtual. The proportional calculation is mathematically sound for normal in-game inputs, division-by-zero is guarded, and empty-truck zero-bonus is correctly handled by reading getNumberBoxes() before unloading. The one point held back is the silent drop-to-zero when MaxBoxes is unconfigured for an upgraded unit, which is an accepted limitation from prior review discussion.
• No files require special attention beyond the already-discussed maxBoxes == 0 fallback in SupplyCenterDockUpdate.cpp.

Important Files Changed

Filename	Overview
GeneralsMD/Code/GameEngine/Include/GameLogic/Module/SupplyTruckAIUpdate.h	Adds getMaxBoxes() as a pure virtual method to SupplyTruckAIInterface and provides an inline implementation in SupplyTruckAIUpdate returning m_maxBoxesData. ChinookAIUpdate, which extends SupplyTruckAIUpdate, inherits the implementation correctly via its SupplyTruckAIUpdateModuleData base. No issues.
GeneralsMD/Code/GameEngine/Include/GameLogic/Module/WorkerAIUpdate.h	Adds the getMaxBoxes() override to WorkerAIUpdate, delegating to m_maxBoxesData on its own module data. Consistent with the SupplyTruckAIUpdate implementation. No issues.
GeneralsMD/Code/GameEngine/Source/GameLogic/Object/Update/DockUpdate/SupplyCenterDockUpdate.cpp	Introduces getUpgradedSupplyBoostValue() helper that correctly snapshots box count before unloading and computes proportional bonus. The maxBoxes > 0 guard prevents division by zero. However, when maxBoxes == 0 and upgradedSupplyBoost > 0, the bonus is silently dropped to 0 (regression vs. unconfigured units), though this case was accepted by the team in prior review threads.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["SupplyCenterDockUpdate::action()"] --> B["getUpgradedSupplyBoostValue(supplyTruckAI)"]
    B --> C{RETAIL_COMPATIBLE_CRC?}
    C -- Yes --> D["return getUpgradedSupplyBoost()  (full flat bonus)"]
    C -- No --> E["maxBoxes = getMaxBoxes()"]
    E --> F{maxBoxes > 0?}
    F -- No --> G["return 0"]
    F -- Yes --> H["upgradedSupplyBoost = getUpgradedSupplyBoost()
deliveredBoxes = getNumberBoxes()"]
    H --> I["return (upgradedSupplyBoost × deliveredBoxes) / maxBoxes"]
    D --> J["value += boost"]
    G --> J
    I --> J
    J --> K["while loseOneBox(): value += getSupplyBoxValue()"]
    K --> L{value > 0?}
    L -- Yes --> M["deposit(value) + floating text"]
    L -- No --> N["return FALSE"]
    M --> N

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_{Last reviewed commit: 67212ba}

[Mauller]

Is the idea that the supply boost is only applied up to maxBoxes?

So if we have a limit of 5 boxes but we deliver 7? we should only be applying the boost to 5 boxes?

Since the above will be under valuing the bonus if so.

[Mauller]

Nvm i misunderstood what it was doing.

But if max boxes is zero then should we be giving any kind of bonus since shouldn't it technically not be able to carry anything?

[tintinhamans]

Good point - units with maxBoxes 0 have no business docking supplies anyways.

[xezon]

Is this Zero Hour only?

[tintinhamans]

Is this Zero Hour only?

No Supply Lines upgrade in Generals, only in ZH.

[xezon]

Code is looking good.