// ===========================================================================
// 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: October 27, 2016
//
//  Procedure Name:
//      texCalculateTexelDensity
//
//  Description:
//      UV workflow function used for calculating the texel density value of
//      input faces
//
//  Input Arguments
//      faces                - String[] - Names of face components.
//      mapSize              - Int      - The texture size to scale against.
//      progressBar          - Int      - Update the progressBar
//
//  Return Values:
//      Float                - The calculated texel density value.
//
//  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 texCalculateTexelDensity(string $faces[], int $mapSize, int $progressBar)
{
	float $area3DSum = 0.0;
	float $area2DSum = 0.0;
	$faces = `filterExpand -ex false -sm 34 $faces`;

	// Begin progressBar
	global string $gMainProgressBar;
	if ($progressBar)
		progressBar -e -bp -max (size($faces)) $gMainProgressBar; 

	float $area3D[] = `polyEvaluate -worldFaceArea $faces`;
	float $area2D[] = `polyEvaluate -uvFaceArea $faces`;
	for ($i = 0; $i < size($area3D); $i++){
		// Break if cancelled by user 
		if ($progressBar && `progressBar -q -isCancelled $gMainProgressBar`) 
		{ 
			warning((uiRes("m_texCalculateTexelDensity.kUvEditorGetTexelDensityInteruptMsg"))); 
			break; 
		}

		$area3DSum += $area3D[$i];
		$area2DSum += $area2D[$i];
		
		// Update the progress window
		if ($progressBar)
			progressBar -e -s 1 $gMainProgressBar; 
	}

	// End progressBar
	if ($progressBar)
		progressBar -e -endProgress $gMainProgressBar;

	return (`sqrt $area2DSum` / `sqrt $area3DSum`) * $mapSize;
}