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/****************************************************************************
**
** Copyright (C) 2014 NVIDIA Corporation.
** Copyright (C) 2017 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt 3D Studio.
**
** $QT_BEGIN_LICENSE:GPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) any later version
** approved by the KDE Free Qt Foundation. The licenses are as published by
** the Free Software Foundation and appearing in the file LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef LUMINANCE_GLSLLIB
#define LUMINANCE_GLSLLIB
// Luma coefficients according to ITU-R Recommendation BT.709 (http://en.wikipedia.org/wiki/Rec._709)
const vec3 yCoeff_709 = vec3( 0.2126, 0.7152, 0.0722 );
float luminance( in vec3 v )
{
return dot( v, yCoeff_709 );
}
vec3 RGBToYPbPr( in vec3 v )
{
vec3 ypp;
ypp.x = luminance( v );
ypp.y = 0.5 * (v.b - ypp.x) / (1.0 - yCoeff_709.b);
ypp.z = 0.5 * (v.r - ypp.x) / (1.0 - yCoeff_709.r);
return ypp;
}
vec3 YPbPrToRGB( in vec3 v )
{
vec3 outRGB;
outRGB.x = dot(vec3(1.0, 0.0, 1.575), v);
outRGB.y = dot(vec3(1.0, -0.187, -0.468), v);
outRGB.z = dot(vec3(1.0, 1.856, 0.0), v);
return outRGB;
}
#endif
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