Hello friends,

I'm working on a game that requires intensive scripting (adventure game) and I experience some difficulties dealing with global properties.

It would be great if someone could help a fellow indie developer. Thanks.

Problem #1 (Solved - see below)

The problem is that in the example provided here: documentation link, we see that:

// Variables that should be accessible through the script.
CObject *g_object = 0;

// A function to register the global properties. 
void RegisterProperties(asIScriptEngine *engine)
{
 // Register variable where the script can store a handle to a CObject type. 
    // Assumes that the CObject type has been registered with the engine already as a reference type.
    r = engine->RegisterGlobalProperty("CObject @g_object", &g_object); assert( r >= 0 );
}

However it doesn't seem to work for me . I do it like this:

int r = 0;

GraphicsObject* go = ((GraphicsObject*)GetEntity("mooseCloth"));
r = engine->RegisterGlobalProperty("GraphicsObject @mooseCloth", &go); SE_ASSERT( r >= 0 );

go = ((GraphicsObject*)GetEntity("topCloth"));
r = engine->RegisterGlobalProperty("GraphicsObject @topCloth", &go); SE_ASSERT( r >= 0 );

go = ((GraphicsObject*)GetEntity("mooseHead"));
r = engine->RegisterGlobalProperty("GraphicsObject @mooseHead", &go); SE_ASSERT( r >= 0 );

Everything compiles without errors, but when I access this objects from script all of them point to the latest declaration "mooseHead". So for example if I go

topCloth.DoStuff();

instead of accessing topCloth it interferes with mooseHead.

What am I doing wrong here?

One thing though, getting rid of this "@" for script variable declaration and "&" for passing the pointer to the object seems to solve that problem. But I'm not sure if it is a good way to go and if there any pitfall involved?

Problem #2 (Solved, see Andreas answer)

I want to declare a variable in a scope of module, so that when the game scene gets destroyed all the global variables are destroyed with it. However I didn't find a way to do that. There is a thing CompileGlobalVar() but it doesn't allow me to pass the pointer to an object and there is no other function to do so (as far as I see), so I'm confused at that point.

There is no ability to destroy/unregister a global variable in the asIScriptEngine as well.

Thanks.

Yaroslav.

Oops, I'm sorry, it is in fact version 2.26.3 and I cant change the name of the topic.

Fixed, need to open full editor to change the name of the topic.

Problem #2 - continuation

Object declarations are now added to the script source code before the compilation. And to initialize a variable I found out that I can get a pointer to a variable and it seems to work, but hell, it looks like a hack that asks for trouble, is it intended use?

int index = mod->GetGlobalVarIndexByName("topCloth");
GraphicsObject** adr = ((GraphicsObject**)mod->GetAddressOfGlobalVar(index));
*adr = (GraphicsObject*)(topClothObject);

Problem #1 - Solution

I've got the answer on the first problem, thanks to Andreas, so I will post it here in case someone will face the same thing.

When you registered the properties with @ you were actually giving the address of the local pointer to the object. You then changed the object the pointer was referring to when registering the other properties, but you still registered the same address to the pointer with AngelScript. This caused all properties to refer to the same object.

Registering properties with @ should be used if the handle can be reassigned by the script to another object. Without the @ the property cannot be reassigned and will refer to the object you've registered throughout the execution.

Now it makes perfect sense.

Still not sure about problem #2 though. If I solved it right or is there another way which I didn't notice?

You can use the GetAddressOfGlobalVar() to inspect and modify the global variables like you found out. Just make sure you update the reference counters of the objects correctly.

int index = mod->GetGlobalVarIndexByName("topCloth");
GraphicsObject** adr = ((GraphicsObject**)mod->GetAddressOfGlobalVar(index));
if( *adr )
 (*adr)->Release();
*adr = (GraphicsObject*)(topClothObject);
if( *adr )
 (*adr)->AddRef();

Regards,

Andreas

You can use the GetAddressOfGlobalVar() to inspect and modify the global variables like you found out. Just make sure you update the reference counters of the objects correctly.

int index = mod->GetGlobalVarIndexByName("topCloth");
GraphicsObject** adr = ((GraphicsObject**)mod->GetAddressOfGlobalVar(index));
if( *adr )
 (*adr)->Release();
*adr = (GraphicsObject*)(topClothObject);
if( *adr )
 (*adr)->AddRef();

Regards,

Andreas

Thanks again, as a suggestion I would add set property methods, so it will be more clear and maybe a little less error prone?

But anyway great stuff. :)