61 lines
2.0 KiB
GLSL
61 lines
2.0 KiB
GLSL
/*
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* This program source code file is part of KICAD, a free EDA CAD application.
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*
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* Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
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* Copyright (C) 2012 Kicad Developers, see change_log.txt for contributors.
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*
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* Fragment shader
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you may find one here:
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* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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* or you may search the http://www.gnu.org website for the version 2 license,
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* or you may write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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// This shader requires GLSL 1.2
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#version 120
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// Input variables
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flat varying vec4 center_;
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flat varying vec2 radius_;
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flat varying vec4 colorA_;
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flat varying vec4 colorB_;
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void main( void )
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{
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// Compute the distance from the circle edge
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float distA = distance( center_, gl_FragCoord ) - radius_.y;
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float distB = radius_.x - distance( center_, gl_FragCoord );
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// Limit the range to [ 0 .. 1 ]
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if( distA < 0 ) distA = 0;
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if( distA > 1 ) distA = 1;
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if( distB < 0 ) distB = 0;
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if( distB > 1 ) distB = 1;
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// Points with a larger distance from the edge are set deeper
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gl_FragDepth = gl_FragCoord.z + distA * 0.001 + distB * 0.001;
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// Compute the color
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vec4 color;
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color.r = colorA_.r;
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color.g = colorA_.g;
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color.b = colorA_.b;
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color.a = colorA_.a * ( 1 - distA ) * ( 1 - distB );
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// Now output the edge fragment color
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gl_FragColor = color;
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}
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