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AE Modding Wiki : Database : GovernmentsModified


This Database concept has been introduced by MrBaggins and described in this post. I am not quite sure if it has been (entirely) implemented and if it works (as advertised). Please update this page if you are MrBaggins or otherwise know what's going on ;-) -- BureauBert


Intro

The GovernmentsModified concept was an idea to allow for flexibility in the structure of the text file databases (for units, buildings, etc.) Specifically it was an idea that the syntax of these be extended to allow for modifications to the individual records, based on government... so for a particular City Improvement, say a Granary, you might have another modified record (of the same improvement) for the Tyranny government... maybe making it cheaper, perhaps. Using this system, you could make Factories more productive, but more polluting under Communism, or Tanks more powerful under Fascism, all without any SLIC, additional identifiers, or code. I altered the db creation code, lexer definitions, and the base template class to achieve this.

What is the syntax?

The following would be the standard defintion of the courthouse.

IMPROVE_COURTHOUSE {
   DefaultIcon ICON_IMPROVE_COURTHOUSE
   Description DESCRIPTION_IMPROVE_COURTHOUSE
   EnableAdvance ADVANCE_JURISPRUDENCE
   ProductionCost 330
   Upkeep 1
   LowerCrime -0.1
}

If you wished to have a courthouse that operated slightly differently under monarchy you'd do the following:

IMPROVE_COURTHOUSE {
   DefaultIcon ICON_IMPROVE_COURTHOUSE
   Description DESCRIPTION_IMPROVE_COURTHOUSE
   EnableAdvance ADVANCE_JURISPRUDENCE
   ProductionCost 330
   Upkeep 1
   LowerCrime -0.1
}

IMPROVE_COURTHOUSE > GOVERNMENT_MONARCHY {
   DefaultIcon ICON_IMPROVE_COURTHOUSE
   Description DESCRIPTION_IMPROVE_COURTHOUSE
   EnableAdvance ADVANCE_JURISPRUDENCE
   ProductionCost 330
   Upkeep 3
   LowerCrime -0.3
   HappyInc -1
}

You should note that this is a modification to an existing record. There must be an record with the same name to allow for a modified record. The syntax using the '>' character allows for multiple government types, separated by commas. It also allows for alpha-numeric (no space) descriptions, which are ignored for purposes of parsing... so

IMPROVE_COURTHOUSE > DecreasedCrime_and_Happy_HarshGovs , 
    GOVERNMENT_MONARCHY, GOVERNMENT_THEOCRACY {

is perfectly valid, and modifies the courthouse record, for the Monarchy and Theocracy govs. Invalid Governments are also ignored, at parsing. There is an additional syntax that can be used within the record structure, that can be used instead of, or as well as, the above syntax...

IMPROVE_COURTHOUSE {
   DefaultIcon ICON_IMPROVE_COURTHOUSE
   Description DESCRIPTION_IMPROVE_COURTHOUSE
   EnableAdvance ADVANCE_JURISPRUDENCE
   ProductionCost 330
   Upkeep 1
   LowerCrime -0.1
}

IMPROVE_COURTHOUSE > Monarchy {
   DefaultIcon ICON_IMPROVE_COURTHOUSE
   Description DESCRIPTION_IMPROVE_COURTHOUSE
   EnableAdvance ADVANCE_JURISPRUDENCE
   GovernmentsModified GOVERNMENT_MONARCHY
   ProductionCost 330
   Upkeep 3
   LowerCrime -0.3
   HappyInc -1
}

It has been mentioned that there are only 64 buildings and 64 wonders. This is actually unrelated to the parser, and has to do with their storage and use within the city data. The GovernmentsModified system ignores this limitation for the modified records. You can still only have 65 buildings, but each of those buildings can have as many modified governments as you need. Essentially the system increases the number of buildings available.

There was a suggestion for another syntax suggested a while back, but from my investigations, its impossible given the current lex definitions, would require a pretty thorough rewrite of the parser, plus would be much more costly in terms of access... something I wanted to avoid... however if a bison/flex pro would like to take a shot...

Code access

This whole system is only half the issue. The database records are accessed via 2 member functions... Get and Access. Get returns a const record, Access the record. While it would be nice to just rewrite the existing Get and Access functions to access the government subrecords, we don't have the context of what government is applicable to do that. I therefore made two overloaded functions...

template  const T *CTPDatabase::Get(sint32 index,sint32 govIndex)
    and
template  T *CTPDatabase::Access(sint32 index,sint32 govIndex)

which work alongside the existing

template  const T *CTPDatabase::Get(sint32 index)
    and
template  T *CTPDatabase::Access(sint32 index)

Notice the extra govIndex parameter. These are overloaded functions, so the existing functions can still be used.

Work we (or maybe just I ) need to do

None of the existing record access in the code (1700 hundred instances of ->Get( and ->Access(, not all of which are applicable,) use the new method... so they need to be changed... This, however, isn't complicated... just a lot of repetition. Here's an example of a couple of changes, that I used to test that the system was working fine...

Original (from CityData::CanBuildBuilding):

const BuildingRecord* irec = g_theBuildingDB->Get(type);

    New:

const BuildingRecord* irec = g_theBuildingDB->Get(type,g_player[m_owner]->GetGovernmentType());

    and, from CityData::CanBuildUnit

const UnitRecord *rec = g_theUnitDB->Get(type);

    becomes

const UnitRecord *rec = g_theUnitDB->Get(type,g_player[m_owner]->GetGovernmentType());
Page last modified on September 19, 2008, at 12:02 AM
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