| /**************************************************************************** |
| ** |
| ** Copyright (C) 2014 NVIDIA Corporation. |
| ** Copyright (C) 2019 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 |
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| ** |
| ** 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 |
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| ****************************************************************************/ |
| |
| |
| // calculate the length of the hypotenuse of a right-angle triangle |
| float hypot( in float x, in float y ) |
| { |
| // (sqrt( x * x + y * y )) might over- or underflow |
| // see http://en.wikipedia.org/wiki/Hypot for details |
| x = abs( x ); |
| y = abs( y ); |
| float t = min( x, y ); |
| x = max( x, y ); |
| t = t/x; |
| return( x * sqrt( 1.0 + ( t * t ) ) ); |
| } |
| |
| float gradientGetPosition( in int gradientMode, in vec2 xy ) |
| { |
| // clamp to [0,1] |
| vec2 tex = xy - floor( xy ); |
| |
| switch( gradientMode ) |
| { |
| case gradient_linear : |
| return( tex.x ); |
| case gradient_squared : |
| return( tex.x * tex.x ); |
| case gradient_box : |
| // gradient is based on the distance from the center |
| return( max( abs( tex.x - 0.5 ), abs( tex.y - 0.5 ) ) ); |
| case gradient_diagonal : |
| // gradient is based on the distance from the diagonal |
| return( sqrt(2.0) * abs( tex.x - tex.y ) ); |
| case gradient_90_degree : |
| // Need to check |
| return( 0.0 ); |
| case gradient_symmetric_90_degree : |
| // Need to check |
| return( 0.0 ); |
| case gradient_radial : |
| // Distance from center |
| return( 2.0 * hypot( tex.x - 0.5, tex.y - 0.5 ) ); |
| case gradient_360_degree : |
| // fall through need to check |
| default : |
| return( 0.0 ); |
| } |
| } |