GameCodingCompleteLinux/Assets/Scripts/PreInit.lua

--========================================================================
-- PreInit.lua : Script that's run when the scripting system is initialized
--
-- Part of the GameCode4 Application
--
-- GameCode4 is the sample application that encapsulates much of the source code
-- discussed in "Game Coding Complete - 4th Edition" by Mike McShaffry and David
-- "Rez" Graham, published by Charles River Media. 
-- ISBN-10: 1133776574 | ISBN-13: 978-1133776574
--
-- If this source code has found it's way to you, and you think it has helped you
-- in any way, do the authors a favor and buy a new copy of the book - there are 
-- detailed explanations in it that compliment this code well. Buy a copy at Amazon.com
-- by clicking here: 
--    http://www.amazon.com/gp/product/1133776574/ref=olp_product_details?ie=UTF8&me=&seller=
--
-- There's a companion web site at http://www.mcshaffry.com/GameCode/
-- 
-- The source code is managed and maintained through Google Code: 
--    http://code.google.com/p/gamecode4/
--
-- (c) Copyright 2012 Michael L. McShaffry and David Graham
--
-- This program is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser GPL v3
-- as published by the Free Software Foundation.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See 
-- http://www.gnu.org/licenses/lgpl-3.0.txt for more details.
--
-- You should have received a copy of the GNU Lesser GPL v3
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
--
--========================================================================

-- This file is run immediately after Lua is created but before the rest of the game initializes.  This is the place
-- to put any language extentions or pure utility functions/classes you write.

-----------------------------------------------------------------------------------------------------------------------
-- Redifinition of require() and dofile().  This is needed to allow scripts to go through the resource system.
-----------------------------------------------------------------------------------------------------------------------
do
	local OldRequire = require;  -- save the old require() function
	local resourceIdMap = {};  -- map of resource id's we've already loaded

	require = function(script)
		-- If we haven't already loaded this file, try to load it now
		if (not resourceIdMap[script]) then
			if (LoadAndExecuteScriptResource(script)) then
				resourceIdMap[script] = true;
			else
				-- failed to load file through the resource system so fall back to the old method
				OldRequire(script)
			end
		end
	end
end

do
	local OldPrint = print;

	print = function(text)
		if (text ~= nil) then
			Log(text);
		else
			Log("<nil>");
		end
	end
end


-----------------------------------------------------------------------------------------------------------------------
-- Utility functions
-----------------------------------------------------------------------------------------------------------------------
Utils = {};

function Utils.DumpTable(table)
	for key, val in pairs(table) do
		print(key, val);
	end
end

-- private function used by Utils.DumpObject()
function Utils._BuildMemberSet(obj, memberSet)
	if (obj.__index ~= nil and obj ~= obj.__index) then
		Utils._BuildMemberSet(obj.__index, memberSet);
	end

	for key, val in pairs(obj) do
		if (key ~= "_index" and memberSet[key] == nil) then
			memberSet[key] = true;
		end
	end
end

function Utils.DumpObject(obj)
	-- There might be copies of the same variable at various levels in the hierarchy so we need to build an
	-- exclusive set of names.
	local memberSet = {};
	Utils._BuildMemberSet(obj, memberSet);

	-- Loop through the set of member names and print them out, along with the value from the original object's
	-- perspective.
	for key,val in pairs(memberSet) do
		print(key, obj[key]);
	end
end

-----------------------------------------------------------------------------------------------------------------------
-- Classes & Inheritance								- Chapter 12, page 349
-----------------------------------------------------------------------------------------------------------------------
function class(baseClass, body)
	local ret = body or {};

	-- if there's a base class, attach our new class to it
	if (baseClass ~= nil) then
		setmetatable(ret, ret);
		ret.__index = baseClass;
		ret.base = baseClass;
	end

	-- Add the Create() function.  This will end up being added to each subclass which isn't ideal.  This 
	-- function should probably be stored in a single place so we only have to create it once.
	-- 		-self: The self pointer that's calling this function.
	--		-constructionData: The table sent in as construction data.  Think of it like a constructor.
	--		-originalSubClass: Used for recursion.  Don't pass anything into this parameter, it's filled 
	--						   automatically.  It's used in case the C++ side needs access to the leaf 
	--						   subclass that is being instantiated.  For an example, see ScriptProcess 
	--						   in C++.
	ret.Create = function(self, constructionData, originalSubClass)
		local obj;
		if (self.__index ~= nil) then
			if (originalSubClass ~= nil) then
				obj = self.__index:Create(constructionData, originalSubClass);
			else
				obj = self.__index:Create(constructionData, self);
			end
		else
			obj = constructionData or {};
		end

		setmetatable(obj, obj);
		obj.__index = self;

		-- copy any operators over
		if (self.__operators ~= nil) then
			for key, val in pairs(self.__operators) do
				obj[key] = val;
			end
		end

		return obj;
	end

	-- Returns true if otherClass appears in this objects class hierarchy anywhere.
	ret.IsInstance = function(self, otherClass)
		local cls = self.__index;
		while cls do
			if cls == otherClass then
				return true
			end
			cls = cls.base
		end
		return false
	end

	return ret;
end