151 lines
4.0 KiB
GLSL
151 lines
4.0 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) 2013-2016 CERN
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* Copyright (C) 2016 Kicad Developers, see authors.txt for contributors.
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* @author Maciej Suminski <maciej.suminski@cern.ch>
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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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#version 120
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// Multi-channel signed distance field
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#define USE_MSDF
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// Shader types
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const float SHADER_FILLED_CIRCLE = 2.0;
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const float SHADER_STROKED_CIRCLE = 3.0;
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const float SHADER_FONT = 4.0;
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const float SHADER_LINE_A = 5.0;
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varying vec4 v_shaderParams;
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varying vec2 v_circleCoords;
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uniform sampler2D u_fontTexture;
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uniform float u_worldPixelSize;
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// Needed to reconstruct the mipmap level / texel derivative
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uniform int u_fontTextureWidth;
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void filledCircle( vec2 aCoord )
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{
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if( dot( aCoord, aCoord ) < 1.0 )
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gl_FragColor = gl_Color;
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else
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discard;
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}
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float pixelSegDistance( vec2 aCoord )
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{
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float aspect = v_shaderParams[1];
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float dist;
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vec2 v = vec2( 1.0 - ( aspect - abs( aCoord.s ) ), aCoord.t );
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if( v.x <= 0.0 )
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{
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dist = abs( aCoord.t );
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}
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else
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{
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dist = length( v );
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}
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return dist;
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}
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int isPixelInSegment( vec2 aCoord )
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{
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return pixelSegDistance( aCoord ) <= 1.0 ? 1 : 0;
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}
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void strokedCircle( vec2 aCoord, float aRadius, float aWidth )
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{
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float outerRadius = max( aRadius, 0.0 );
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float innerRadius = max( aRadius - aWidth, 0.0 );
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if( ( dot( aCoord, aCoord ) < 1.0 ) &&
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( dot( aCoord, aCoord ) * ( outerRadius * outerRadius ) > innerRadius * innerRadius ) )
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gl_FragColor = gl_Color;
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else
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discard;
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}
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void drawLine( vec2 aCoord )
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{
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if( isPixelInSegment( aCoord ) != 0)
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gl_FragColor = gl_Color;
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else
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discard;
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}
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#ifdef USE_MSDF
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float median( vec3 v )
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{
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return max( min( v.r, v.g ), min( max( v.r, v.g ), v.b ) );
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}
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#endif
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void main()
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{
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// VS to FS pipeline does math that means we can't rely on the mode
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// parameter being bit-exact without rounding it first.
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float mode = floor( v_shaderParams[0] + 0.5 );
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if( mode == SHADER_LINE_A )
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{
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drawLine( gl_TexCoord[0].st );
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}
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else if( mode == SHADER_FILLED_CIRCLE )
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{
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filledCircle( v_circleCoords );
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}
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else if( mode == SHADER_STROKED_CIRCLE )
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{
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strokedCircle( v_circleCoords, v_shaderParams[2], v_shaderParams[3] );
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}
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else if( mode == SHADER_FONT )
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{
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vec2 tex = v_shaderParams.yz;
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// Unless we're stretching chars it is okay to consider
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// one derivative for filtering
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float derivative = length( dFdx( tex ) ) * u_fontTextureWidth / 4;
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#ifdef USE_MSDF
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float dist = median( texture2D( u_fontTexture, tex ).rgb );
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#else
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float dist = texture2D( u_fontTexture, tex ).r;
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#endif
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// use the derivative for zoom-adaptive filtering
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float alpha = smoothstep( 0.5 - derivative, 0.5 + derivative, dist ) * gl_Color.a;
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gl_FragColor = vec4( gl_Color.rgb, alpha );
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}
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else
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{
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// Simple pass-through
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gl_FragColor = gl_Color;
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}
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} |