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asIScriptGeneric with object method possible?

Started by ruphert Oct 20, 2012 at 9:18 PM 5 replies 2.3k views

Original Post

Oct 20, 2012 at 9:18 PM

I'm trying to register a variable parameter method like in this example: http://www.angelcode.com/angelscript/sdk/docs/manual/doc_adv_var_type.html
but in an object.

r = engine->RegisterObjectMethod("JGizmo", "void KeepInBounds( ?∈ )",
asMETHOD( JGizmo, call),
asCALL_GENERIC); assert( r >= 0 );

but it fails to register with code: asWRONG_CALLING_CONV

with asCALL_THISCALL it just crashes when accessing the asIScriptGeneric object.

Is this possible at all for object methods?

SiCrane

Oct 20, 2012 at 9:29 PM

Function pointers registered with asCALL_GENERIC must have the type void (*)(asIScriptGeneric *) this means that they cannot be member functions.

WitchLord

Oct 21, 2012 at 2:09 AM

You're confusing the concepts

The asIScriptGeneric is used for the generic calling convention, which is for when native calling conventions are not supported

The variable type, ?&, is used to pass any argument type to a function, and yes they can be used with object methods too.

In your case the object method should be implemented like this:


 void JGizmo::KeepInBounds( void *ptr. int typeId )
 {
 // Determine the type of the argument with the typeId, and then cast the ptr accordingly with reinterpret_cast.
 }
 
 // Register it as
 engine->RegisterObjectMethod("JGizmo", "void KeepInBounds(?∈)", asMETHOD(JGizmo, KeepInBounds), asCALL_THISCALL);

Regards,
Andreas

ruphert

Oct 22, 2012 at 8:55 AM

Thanks Andreas I suspected that worked. But I want to specifically use asIScriptGeneric* because this function will have variable number of parameters:
void KeepInBounds(?∈)
void KeepInBounds(?∈, ?∈)
void KeepInBounds(?∈, ?∈, ?∈)
etc.

WitchLord

Oct 22, 2012 at 1:20 PM

Then the function must be implemented like this:


 // Global function, or static class method
 void MyGenericFunction(asIScriptGeneric *gen)
 {
 for( asUINT n = 0; n < gen->getArgCount(); n++ )
 {
 int type = gen->GetArgTypeId(n);
 void *ptr = gen->GetAddressOfArg(n);
 
 ... reinterpret_cast the pointer according to its type
 }
 }

Regards,
Andreas

ruphert

Nov 2, 2012 at 1:13 PM

Thanks this helped.
Still I would find it super useful to have generic parameters in objects like:

void CObject::MyGenericFunction(asIScriptGeneric *gen)

why can't that work? Any chance of it happening?

SiCrane

Nov 2, 2012 at 1:29 PM

You can just register a proxy function if you want that behavior. Something like:


 void generic_proxy(asIScriptGeneric * gen) {
 CObject * self = static_cast<CObject *>(gen->GetObject());
 self->MyGenericFunction(gen);
 }

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