Calling LUA Script function from C++ with arguments?

[Roland]

Calling a Lua Script function from C++ without arguments works just fine. No problem. But when it comes to bringing along an argument I need some hint. Here is an example.

 

LUA:

Script.myval = 10

function Script::increment()
self.myval = self.myval + 1
end

function Script::add( val )
self.myval = self.myval + val
end

 

C++: (assuming we have the entity to which the script attached)

 

entity->CallFunction( "increment" ); // works fine. no problem

 

Any idea how to add argument for the call of "add" ? I understand that this has to be done using the Interpreter class. But how ?

[Josh]

Here's an example:

	bool Entity::CallFunction(const std::string& name, Entity* entity, const Vec3& position, const Vec3& normal, const float speed)
{
	if (component==NULL) return false;
	bool success = false;

	//Get the component table
	int stacksize = Interpreter::GetStackSize();

	//Get the global error handler function
	int errorfunctionindex = 0;
#ifdef DEBUG
	Interpreter::GetGlobal("LuaErrorHandler");
	errorfunctionindex = Interpreter::GetStackSize();
#endif
	Push();
	Interpreter::GetField("script");
	if (Interpreter::IsTable())
	{
		Interpreter::GetField(name);
		if (Interpreter::IsFunction())
		{
			Interpreter::PushValue(-2);//Push script table onto stack
			Interpreter::PushObject(entity);
			Interpreter::PushVec3(position);
			Interpreter::PushVec3(normal);
			Interpreter::PushFloat(speed);
#ifdef DEBUG
			errorfunctionindex = -(Interpreter::GetStackSize()-errorfunctionindex+1);
#endif
			success = Interpreter::Invoke(5,0,errorfunctionindex);
		}
	}
	Interpreter::SetStackSize(stacksize);
	return success;
}

[Roland]

Thank's a lot Josh. Works like a charm

[beo6]

So what is the extra Object pointer good for in this method?

bool CallFunction(const std::string& name, Object* extra=NULL);

[Josh]

It's an argument that will be passed to the Lua function, if present.