New Feature: Support Convert to another type.

[frg2089]

Summary

Refactored the underlying type conversion system (ConvertToType / ConvertToTypeEx) to support cross-type conversion between all TechnoType classes except AircraftType. Added UndeploysInto.ConvertTo as a new conversion trigger on BuildingType.

Changes

Core: rewritten conversion logic

• ConvertToType and new ConvertToTypeEx now handle cross-type conversion via creating a new object + destroying the old one, supporting InfantryType, UnitType, and BuildingType.
• AircraftType is only supported for same-type conversion (in-place type pointer update).
• Deferred conversion via PendingConvertTechnoType processed in OnEarlyUpdate — used when the source unit needs to finish its current animation frame before being destroyed.

This improvement applies to all existing conversion paths (Convert.Deploy, Convert.Undeploy, Convert.HumanToComputer, Convert.ComputerToHuman, etc.).

New feature: UndeploysInto.ConvertTo

• BuildingType tag UndeploysInto.ConvertTo specifies a target TechnoType.
• After UndeploysInto creates the vehicle, it is converted to the target type on the next frame.
• The resulting unit inherits the vehicle's move order, destination, and selection state.
• Mind control, shields, invulnerability, and attached effects are transferred.

Refactor

• Moved TransferMindControlOnDeploy from Hooks.DeploysInto.cpp into TechnoExt as a reusable static method.

Selection preservation

• Both deploy (infantry → building) and undeploy convert (vehicle → other) now preserve the original unit's selection state on the new unit.

Documentation

Updated New-or-Enhanced-Logics.md with documentation for UndeploysInto.ConvertTo, the expanded type support in Convert.Deploy / Convert.Undeploy, and a warning that cross-type conversion creates a new object and destroys the old one.

Files Changed

File	Change
src/Ext/Techno/Body.cpp	ConvertToTypeEx cross-type conversion, ConvertToType same-type fallback, property transfer
src/Ext/Techno/Body.h	PendingConvertTechnoType, static method declarations
src/Ext/Techno/Body.Update.cpp	Deferred conversion processing
src/Ext/Unit/Hooks.DeploysInto.cpp	Delegate to TechnoExt, add UndeploysInto.ConvertTo hook
src/Ext/BuildingType/Body.h/.cpp	UndeploysInto.ConvertTo tag
docs/New-or-Enhanced-Logics.md	Documentation

[github-actions]

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[TaranDahl]

Not quite sure about the inheritance status section. MissionStatus may also be considered. And whether buildings should skip the inheritance of some attributes.

[TaranDahl]

@NetsuNegi @Coronia @DeathFishAtEase

[DeathFishAtEase]

Huh,

• Q: Should a building that has UndeploysInto inherit the destination?

This kind of issue might need a toggle.

[TaranDahl]

Building has no destination.

[DeathFishAtEase]

no destination

That is an example of behavior such as a moving vehicle immediately undeploying after conversion and continuing to the target location.

Alternatively: if a unit becomes a building under unload mission, should the building inherit the unload mission to attack the ground directly below... and so on.