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Getting a DataBlock from C

by Steve Bilton · in Torque Game Engine · 01/10/2008 (8:57 am) · 10 replies

Apologies in advance if this is a stupid question, but I've been trawling the forums and docs but can't seem to find the answer to what I assume is a fairly simple question.

I'm trying to grab hold of fields within a datablock defined in scripts while in C++.

So my scripts have:


datablock PlayerData(DemoPlayer : PlayerBody)
{
someField = 10;
};


Then in C++, I have the following:


// Get my current player that I'm dealing with - this could well be very ugly.
SimObject* object = 0;
Sim::findObject(dAtoi(Con::getVariable("$AIManager::currentPathPlayer")), object);

player = (AIPlayer*)object;

if ( player )
{
GameBaseData dataBlock = player->getDataBlock();
const char* myField = datablock->getDataField(someField, NULL);
}


I'm getting myField as NULL, but it gets dataBlock okay. The question, then, is how I get my field from the specified datablock?

Cheers
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Associate Orion Elenzil
Real Life Plus
#1
01/10/2008 (10:00 am)
Looking at the code, it looks like the input param there needs to be a StringTableEntry, so:
const char* myField = datablock->getDataField(StringTable->insert(someFieldName), NULL);

Associate Orion Elenzil
Real Life Plus
#2
01/10/2008 (10:00 am)
Also, and call me a terrible programmer if you want, you could consider making the field public, so:
const char* myField = datablock->someField;

Steve Bilton
#3
01/10/2008 (10:14 am)
Excellent, the string table grab worked, cheers. Out of interest, why was the string table necessary? Is there a link to some information at what is actually going on here?

As an aside on your second comment, I wasn't aware you could set a field to be public/private within the scripts ... as this is the only place myField was declared.

Associate Orion Elenzil
Real Life Plus
#4
01/10/2008 (10:32 am)
Oh, sorry - i take back my second comment; i didn't read your post closely enough.

the StringTable's reason for existence is that it always returns the same const char* for the same input string, so that later you can just compare the const char*s directly with "==" instead of using strcmp().
.. which is what's going on in SimFieldDictionary::getFieldValue():

const char *SimFieldDictionary::getFieldValue(StringTableEntry slotName)
{
   U32 bucket = HashPointer(slotName) % HashTableSize;

   for(Entry *walk = mHashTable[bucket];walk;walk = walk->next)
      [b]if(walk->slotName == slotName)[/b]
         return walk->value;
   return NULL;
}

Steve Bilton
#5
01/10/2008 (10:37 am)
Ah right, I get you. Ta. =)

Employee Michael Perry
ZombieShortbus
#6
01/10/2008 (10:47 am)
@Orion - I'd call you a terrible programmer, but the whole pot calling the kettle black thing would come into play =)

Torque 3D Owner Lukas Macura
CINEMAX GAMES
#7
08/03/2009 (8:05 am)
this work well

const char* myField = datablock->getDataField(StringTable->insert(someFieldName), NULL);

but what should be as parament array when i want access to array value
when i access to "test[1,1]"
i try those 2 variants and nothing work

const char* myField = datablock->getDataField(StringTable->insert("test"), "1,1");
const char* myField = datablock->getDataField(StringTable->insert("test"), "1_1");

Associate Orion Elenzil
Real Life Plus
#8
08/03/2009 (9:56 am)
i think there may be a special version of getDataField to deal w/ array'd fields.

Torque Owner Wes Macdonald
#9
08/03/2009 (11:05 am) 
const char* myField = datablock->getDataField(StringTable->insert("test"), "1_1");
That is exactly how to do it. It wont work for static fields but you cannot expose multidimensional arrays to script through static fields anyway.

Torque 3D Owner Lukas Macura
CINEMAX GAMES
#10
08/03/2009 (9:58 pm)
You are right, this code work, i had typo in it...

const char* myField = datablock->getDataField(StringTable->insert("test"), "1_1");