// ===========================================================================
// Copyright 2018 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
// ===========================================================================
//
//  Creation Date: November 26, 2016
//
//  Procedure Name:
//      texIsCounterClockwise
//
//  Description:
//      UV workflow function used for calculating the 2D cross product of the
//      vectors between three points in 2D space (UV coordinates). The
//      calculation is on the the points making up the vectors OA and OB
//      (ie. the Z-component of 2D coordinates 3D cross product).
//
//  Input Arguments
//      O                    - Float[] - U and V coordinate of UV point O
//      A                    - Float[] - U and V coordinate of UV point A
//      B                    - Float[] - U and V coordinate of UV point B
//
//  Return Value:
//      Float                - Either zero, a positive or negative value.
//                             Positive: OAB makes a counter-clockwise turn.
//                             Negative: OAB makes a clockwise turn.
//                             Zero: All three points are collinear.
//
//  Notes:
//  This script is part of the implementation of Nightshade UV Editor into
//  Autodesk Maya. This script is sourced by other scripts. Do not run it 
//  directly.
//
// ===========================================================================

global proc float texIsCounterClockwise(float $O[], float $A[], float $B[]){
    float $value = ($A[0] - $O[0]) * ($B[1] - $O[1]) - ($A[1] - $O[1]) * ($B[0] - $O[0]);

    return $value;
}