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Access prefab Sub Objects from torquescript

by Andrew Edmonds · 01/30/2010 (3:13 pm) · 4 comments

I use a prefab that I have created containing one object and 8 lights. I wanted a way to turn the lights on and off in-game and couldn't find a way to access the sub objects of a prefab through script (without exploding the prefab). These functions will allow you to access any object inside of a prefab.

Usage:
%prefab.getSubObjectCount() -- returns the number of objects inside the prefab
%prefab.getSubObject(%objectIndex) -- returns the id of the object at the specified index

The code:
In T3D\prefab.h at line 72 (in public declarations), add

// getSubObjectCount and getSubObject >>>
S32 getSubObjectCount();
S32 getSubObject(S32 subObjectIndex);
// getSubObjectCount and getSubObject <<<


Add to the end of T3D\prefab.cpp:

// getSubObjectCount and getSubObject >>>
S32 Prefab::getSubObjectCount()
{
   if (!mChildGroup) {
      Con::errorf("Not a prefab or no subObjects found.");
      return NULL;
   }

   SimGroup *group = mChildGroup;
   Vector<SceneObject*> foundObjects;

   group->findObjectByType(foundObjects);

   return foundObjects.size();
}

ConsoleMethod(Prefab, getSubObjectCount, S32, 2, 2, "prefab.getSubObjectCount() returns the number of subObjects inside the prefab.")

{
   TORQUE_UNUSED(argc); TORQUE_UNUSED(argv);

   return object->getSubObjectCount();

}

S32 Prefab::getSubObject(S32 subObjectIndex)
{
   if (!mChildGroup) {
      Con::errorf("Not a prefab or no subObjects found.");
      return NULL;
   }

   SimGroup *group = mChildGroup;
   Vector<SceneObject*> foundObjects;

   group->findObjectByType(foundObjects);

   S32 subObjectsCount = foundObjects.size();

   if (subObjectIndex >= subObjectsCount) {
      Con::errorf("%i out of bounds.", subObjectIndex);
      return NULL;
   }

   SceneObject *child = foundObjects[subObjectIndex];
   return child->getId();
}

ConsoleMethod(Prefab, getSubObject, S32, 3, 3, "prefab.getSubObject(index) returns an object within the prefab.")
{
   TORQUE_UNUSED(argc);
   S32 subObjectIndex = dAtoi(argv[2]);
   return object->getSubObject(subObjectIndex);
}
// getSubObjectCount and getSubObject <<<

Recompile and you're done!
Andrew Edmonds's profile picture
Torque Owner Andrew Edmonds
EiKON Games

About the author

Formed in 2005, EiKON Games is an indie games development project based in the UK working on the tactical first person shooter "Epoch: Incursion". See the Join Us or Contact Us pages at http://www.eikon-games.com/

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Associate Konrad Kiss
Bitgap Games
#1
01/30/2010 (3:22 pm)
Awesome, thanks! This should be stock!

Associate James Ford
Sickhead Games
#2
03/13/2010 (7:32 pm)
The next release will include a Prefab::onLoad( %this, %simgroup ) callback where %simgroup contains all child objects of the prefab. I'll also add %prefab.getChildGroup() or something similar.

Torque 3D Owner Ted Southard
#3
05/19/2010 (9:24 pm)
This is very useful! Something it led me to was the need to get the prefab by the sub object's ID. What I did to make that work were the following changes...

In prefab.h at the end of the prefab class make the last two members public, by changing:
/// Lookup from a child object's id to its transform in 
   /// this Prefab's object space.
   ChildToMatMap mChildMap;

   typedef Map<SimObjectId,SimObjectId> ChildToPrefabMap;

   /// Lookup from a SimObject to its parent Prefab if it has one.
   static ChildToPrefabMap smChildToPrefabMap;
};

To:
/// Lookup from a child object's id to its transform in 
   /// this Prefab's object space.
   ChildToMatMap mChildMap;

public:  //<<<--Insert this

   typedef Map<SimObjectId,SimObjectId> ChildToPrefabMap;

   /// Lookup from a SimObject to its parent Prefab if it has one.
   static ChildToPrefabMap smChildToPrefabMap;
};

And insert the following at the end of prefab.cpp:
ConsoleFunction(getPrefabByChildID, S32, 2, 2, "getPrefabByChildID(id) returns the object's owning prefab.")
{
   TORQUE_UNUSED(argc);
   S32 subObjectIndex = dAtoi(argv[1]);

	Prefab::ChildToPrefabMap::Iterator itr = Prefab::smChildToPrefabMap.find( subObjectIndex );
   if ( itr == Prefab::smChildToPrefabMap.end() )
      return NULL; 

   Prefab *prefab;
   if ( !Sim::findObject( itr->value, prefab ) )
   {
      Con::errorf( "Prefab::getPrefabByChildID - child object mapped to a prefab that no longer exists." );
      return NULL;
   }

	return prefab->getId();
}

I'm not sure if exposing those ChildToPrefabMap variables has any negative side-effects, though in using it I haven't noticed anything detrimental.

Torque Owner Vincent BILLET
Default Studio Name
#4
12/10/2012 (4:26 pm)
This can also be done only with torqueScript in T3D 1.2 (MIT) :
Create scripts/server/prefabsExt.cs
function Prefab::onLoad(%prefab,%sim)
{
   %prefab.TheSimGroup = %sim;
}

function Prefab::getSubObjectCount(%prefab)
{
   return %prefab.TheSimGroup.getObjectCount();
}

function Prefab::getSubObject(%prefab,%idx)
{
   return %prefab.TheSimGroup.getObject(%idx);
}
And in scripts/server/game.cs, after execs, add
exec("scripts/server/prefabsExt.cs");
That's done.