----------------------------------------------------------------------------------------
-- ------------------------------ SOME USEFUL FUNCTIONS ----------------------------- --
----------------------------------------------------------------------------------------

-- global variables
global g_MAX = false;
global g_MAX_use_listener = false;

-- global structures
struct exportOptions (sampleRate, ikSampleRate, scale, flipyz, flipNormal, exportColours, exportUV, UVchannels, exportHelpers);
struct exportAnims (names, startframes, endframes, lengths) ;

global Anims;
global Options;

global OgreExportFloater;
global OgreExportOptions, OgreExportObject, OgreExportMesh, OgreExportAnimation, OgreExportMaterial, OgreExportAbout;

--------------------------------------------------------------------
-- compute the transform, if you want to flip Y and Z axis,
-- because the axis which 'defines height' in OGRE is the Y axis,
-- whereas 3dsmax uses the Z one.
--------------------------------------------------------------------
function flipYZTransform Tform = (
	local axis1,axis2,axis3,t,m
	
	-- computes the matrix
	axis1 = point3 1 0 0 ;
	axis2 = point3 0 0 1 ;
	axis3 = point3 0 -1 0 ;
	t = point3 0 0 0 ;
	m=matrix3 axis1 axis2 axis3 t ;
	
	-- multiplies by the inverse
	Tform = Tform*inverse(m) ;

	return Tform ;
)

-----------------------------------------------------------------------------
-- check if the bone is the root object of the biped
-----------------------------------------------------------------------------
function isPelvis bipObj =
(
	if (bipObj == undefined) then return false ;
	if (classof bipObj != Biped_Object) then return false;
	return ((biped.getNode bipObj 13) == bipObj) ;
)


-----------------------------------------------------------------------------
-- check if the bone is the footstep object of the biped
-----------------------------------------------------------------------------
function isFootStep bipObj =
(
	if (bipObj == undefined) then return false ;
	if (classof bipObj != Biped_Object) then return false;
	return ((biped.getNode bipObj 16) == bipObj) ;
)


--------------------------------------------------------------------
-- returns if the bone is the root or not,
-- ia if its parent is undefined or is not a bone.
--------------------------------------------------------------------
function isRoot b = (
	if (b.parent==undefined or not (iskindof b.parent BoneGeometry or iskindOf b.parent Biped_Object) ) then
		return true ;
	else
		return false ;
	
)

--------------------------------------------------------------------
-- returns if the bone is the root or not,
-- handles standard bones as well as biped
--------------------------------------------------------------------
function isRootUniversal b = (
	if (isRoot b) then
		return true; 
	else if (isPelvis b) then
		return true;
	else
		return false;
)

--------------------------------------------------------------------
-- returns if the object is a root or not,
-- handles any kind oj object
--------------------------------------------------------------------
function isRootUniversal2 b = (
	bname = replaceSpaces b.name;
	ind = (findItem RootsList bname);
	if (ind == 0) then
		return false;
	else
		return true;
)

--------------------------------------------------------------------
-- returns if the object is part of the skin (or physique modifier)
--------------------------------------------------------------------
function isPartOfModifier b sk phy = (
	name = replaceSpaces b.name ;
	if (sk!=undefined) then
	(
		for i=1 to (skinOps.GetNumberBones sk) do
		(
			bname = skinOps.GetBoneName sk i 1 ;
			replaceSpaces bname ;
			if (name == bname) then
				return true;
		)
	)
	else if (phy!=undefined) then
	(
		for i=1 to (physiqueOps.GetBoneCount $) do
		(
			bname = (physiqueOps.GetBones $)[i].name;
			replaceSpaces bname ;
			if (name == bname) then
				return true;
		)
	)
	return false;
)

--------------------------------------------------------------------
-- creates a new array (which must be set up as an array before
-- calling this function) in which there isn't the same element.
-- Moreover, the array is sorted.
--------------------------------------------------------------------

function keepLoneValues a b= (
	local e, last_e ;
	sort a ;
	last_e = undefined ;
	for e in a do (
		if (e!=last_e) then 
			append b e ;
		last_e = e ;
	)
)

---------------------------------------------------------------------
-- replaces " " by "_" in a string.
-- when a name is for example Left Biceps max knows it at Left_Biceps
-- and execute function will not work if you don't use this function
---------------------------------------------------------------------
function replaceSpaces s =
(
	for i=1 to s.count do
	(
		if (s[i] == " ") then
			s[i] = "_" ;
	)
	s ;
)

--------------------------------
-- return the length of an array
--------------------------------
function arrayLength a = 
(
	local i ;
	i = 1 ;
	while (a[i] != undefined) do
		i = i + 1 ;	
	i-1 ;
)

-----------------------------------------------------------------------------
-- return the skin modifier or undefined if object don't have a skin modifier
-----------------------------------------------------------------------------
function getSkin obj =
(
	local s,i ;
	s = undefined ;
	if obj != undefined then
		for i in obj.modifiers do
		(
			if iskindof i Skin do
				s = i ;
		)
	s ;
)


-----------------------------------------------------------------------------
-- return the physique modifier or undefined if object don't have it
-----------------------------------------------------------------------------
function getPhysique obj =
(
	local s,i ;
	s = undefined ;
	if obj != undefined then
		for i in obj.modifiers do
		(
			if iskindof i Physique do
				s = i ;
		)
	s ;
)

-----------------------------------------------------------------------------
-- return the OctopusExport modifier or undefined if object don't have it
-----------------------------------------------------------------------------
function getOctopusExport obj =
(
	local s,i ;
	s = undefined ;
	if obj != undefined then
		for i in obj.modifiers do
		(
			if iskindof i OctopusMeshModifier do
				s = i ;
		)
	s ;
)

--------------------------------------------------
-- return an Array with the root bones of the skin
--------------------------------------------------

function getRoots skin =
(
	local rootstab,n,i,c,d ;
	rootstab = #() ;
	n = skinOps.GetNumberBones skin ;
	for i = 1 to n do
	(
		c= skinOps.GetBoneName skin i 1 ;
		replaceSpaces c ;
		d = getNodeByName c ;
		if (isRoot d) then
			append rootstab d ;
	)
	rootstab ;
)

--------------------------------------------------------
-- return an Array with the ID of root bones of the skin
--------------------------------------------------------

function getRootsId skin =
(
	local rootstab,n,i,c,d ;
	rootstab = #() ;
	n = skinOps.GetNumberBones skin ;
	for i = 1 to n do
	(
		c= skinOps.GetBoneName skin i 1 ;
		replaceSpaces c ;
		d = getNodeByName c ;
		if (isRoot d) then
			append rootstab i ;
	)
	rootstab ;
)

-------------------------------------------------------
-- return a angleAxis given a Quaternion
-------------------------------------------------------

function toAngleAxis q =
(
	local angle, axis;
	local result;
	
	fSqrLength = q.x*q.x+q.y*q.y+q.z*q.z ;
	if (fSqrLength > 0.0) then
	(
		angle = ((acos q.w) * pi / 90);
		fInvLength = 1.0 / (sqrt fSqrLength);
		axis = [q.x*fInvLength, q.y*fInvLength, q.z*fInvLength];
		result = angleAxis angle axis;
	)
	else
	(
		angle = 0;
		axis = [1,0,0];
		result = angleAxis angle axis;
	)
	
	return result;
)