source: downloads/Tools/3dsmaxExport/MaxscriptExport/scripts/ogre/lib/OgreSkeletonLib_usefulfns.ms @ 6

----------------------------------------------------------------------------------------
-- ------------------------------ 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;
)