kicad/common/gal/opengl/shader.vert

100 lines
3.3 KiB
GLSL

/*
* This program source code file is part of KICAD, a free EDA CAD application.
*
* Copyright (C) 2013 CERN
* @author Maciej Suminski <maciej.suminski@cern.ch>
*
* Vertex shader
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
#version 120
// Shader types
const float SHADER_LINE = 1.0f;
const float SHADER_FILLED_CIRCLE = 2.0f;
const float SHADER_STROKED_CIRCLE = 3.0f;
// Minimum line width
const float MIN_WIDTH = 1.0f;
attribute vec4 attrShaderParams;
varying vec4 shaderParams;
varying vec2 circleCoords;
void main()
{
// Pass attributes to the fragment shader
shaderParams = attrShaderParams;
if( shaderParams[0] == SHADER_LINE )
{
float lineWidth = shaderParams[3];
float worldScale = gl_ModelViewMatrix[0][0];
float scale;
// Make lines appear to be at least 1 pixel wide
if( worldScale * lineWidth < MIN_WIDTH )
scale = MIN_WIDTH / ( worldScale * lineWidth );
else
scale = 1.0f;
gl_Position = gl_ModelViewProjectionMatrix *
( gl_Vertex + vec4( shaderParams.yz * scale, 0.0, 0.0 ) );
}
else if( ( shaderParams[0] == SHADER_STROKED_CIRCLE ) ||
( shaderParams[0] == SHADER_FILLED_CIRCLE ) )
{
// Compute relative circle coordinates basing on indices
// Circle
if( shaderParams[1] == 1.0f )
circleCoords = vec2( -sqrt( 3.0f ), -1.0f );
else if( shaderParams[1] == 2.0f )
circleCoords = vec2( sqrt( 3.0f ), -1.0f );
else if( shaderParams[1] == 3.0f )
circleCoords = vec2( 0.0f, 2.0f );
// Semicircle
else if( shaderParams[1] == 4.0f )
circleCoords = vec2( -3.0f / sqrt( 3.0f ), 0.0f );
else if( shaderParams[1] == 5.0f )
circleCoords = vec2( 3.0f / sqrt( 3.0f ), 0.0f );
else if( shaderParams[1] == 6.0f )
circleCoords = vec2( 0.0f, 2.0f );
// Make the line appear to be at least 1 pixel wide
float lineWidth = shaderParams[3];
float worldScale = gl_ModelViewMatrix[0][0];
// Make lines appear to be at least 1 pixel width
if( worldScale * lineWidth < MIN_WIDTH )
shaderParams[3] = shaderParams[3] / ( worldScale * lineWidth );
gl_Position = ftransform();
}
else
{
// Pass through the coordinates like in the fixed pipeline
gl_Position = ftransform();
}
gl_FrontColor = gl_Color;
}