Units' bonus requirements and obsoletion

[migck]

I'm trying to create a little addon of resources used as requirements to build some modern units, but so that when the resource becomes obsolete with a certain tech it is no longer needed to build that unit.
Specifically, I'm trying to implement this for a Rubber resource, used to build some modern units like Tanks and Infantry, but being no longer needed once the player discovers Plastics.
I have identified the function controlling requirements to train units in:

CvPlot::canTrain(UnitTypes eUnit, bool bContinue, bool bTestVisible) const

I know the best thing would be to create new XML fields defining such behavior, but for such a focused feature, I prefer not to dabble into that yet.
The thing is, I don't know how to add the structure to evaluate the owner of the unit, and whether he has Plastics tech there.
Any help is appreciated.

 

[platyping]

use python canTrain callback then if you dont want to use SDK

 

[migck]

I do want to modify the SDK, specifically that function in CvPlot.cpp. I just meant I wouldn't want having to add a new XML field, which I don't even know how would it be implemented, to all units and/or bonuses.

 

[CyberChrist]

It might be easier to make a National Wonder that provides 1 Rubber and becomes available with Plastics representing synthetic rubber production (although synthetic rubber doesn't actually replace the need for natural rubber entirely in the real world).

 

[migck]

Interesting, I figured that industry and science would have already replaced natural rubber completely. But I guess the same happens with fur, whales and ivory, they eventually become obsolete in Civ yet nowadays they are still thriving businesses, which is a bit tragic IMO (and I have also made a Tobacco resource that goes obsolete with Medicine, go figure )
Anyways, I have managed to implement my idea not just for rubber, but for all obsolete resources required to train units:

Spoiler :

for AND bonuses:

/**	Tweaked - ignore obsolete bonuses	**/
/**	Original	**
if (GC.getUnitInfo(eUnit).getPrereqAndBonus() != NO_BONUS)
/**	Original END	**/
if (GC.getUnitInfo(eUnit).getPrereqAndBonus() != NO_BONUS && !GET_TEAM(getTeam()).isBonusObsolete((BonusTypes)GC.getUnitInfo(eUnit).getPrereqAndBonus()))
/**	Tweaked END	**/

and for OR resources

/**	Tweaked - ignore obsolete bonuses	**/
/**	Original	**
if (GC.getUnitInfo(eUnit).getPrereqOrBonuses(iI) != NO_BONUS)
/**	Original END	**/
if (GC.getUnitInfo(eUnit).getPrereqOrBonuses(iI) != NO_BONUS && !GET_TEAM(getTeam()).isBonusObsolete((BonusTypes)GC.getUnitInfo(eUnit).getPrereqOrBonuses(iI)))
/**	Tweaked END	**/

Though the obsolete bonus still appears as a requirement in red in case the unit needs two bonuses and the player is lacking the non-obsolete one.

 

[CyberChrist]

There is actually a rising shortage of natural rubber these days, mainly due to a constantly increasing demand for it for tyre production.