FreeTypeGL-0.0.1: shaders/agg.frag
/* =========================================================================
* Freetype GL - A C OpenGL Freetype engine
* Platform: Any
* WWW: http://code.google.com/p/freetype-gl/
* -------------------------------------------------------------------------
* Copyright 2011 Nicolas P. Rougier. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY NICOLAS P. ROUGIER ''AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL NICOLAS P. ROUGIER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are
* those of the authors and should not be interpreted as representing official
* policies, either expressed or implied, of Nicolas P. Rougier.
* ========================================================================= */
/* =========================================================================
* Freetype GL - A C OpenGL Freetype engine
* Platform: Any
* WWW: http://code.google.com/p/freetype-gl/
* -------------------------------------------------------------------------
* Copyright 2011 Nicolas P. Rougier. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY NICOLAS P. ROUGIER ''AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL NICOLAS P. ROUGIER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are
* those of the authors and should not be interpreted as representing official
* policies, either expressed or implied, of Nicolas P. Rougier.
* ========================================================================= */
uniform sampler2D texture;
uniform vec2 pixel;
uniform float gamma;
varying float m;
uniform float primary, secondary, tertiary;
vec3
energy_distribution( vec4 previous, vec4 current, vec4 next )
{
// Energy distribution as explained on:
// http://www.grc.com/freeandclear.htm
//
// .. v..
// RGB RGB RGB
// previous.g + previous.b + current.r + current.g + current.b
//
// . .v. .
// RGB RGB RGB
// previous.b + current.r + current.g + current.b + next.r
//
// ..v ..
// RGB RGB RGB
// current.r + current.g + current.b + next.r + next.g
float r =
tertiary * previous.g +
secondary * previous.b +
primary * current.r +
secondary * current.g +
tertiary * current.b;
float g =
tertiary * previous.b +
secondary * current.r +
primary * current.g +
secondary * current.b +
tertiary * next.r;
float b =
tertiary * current.r +
secondary * current.g +
primary * current.b +
secondary * next.r +
tertiary * next.g;
return vec3(r,g,b);
}
void main() {
vec2 uv = gl_TexCoord[0].xy;
vec4 current = texture2D(texture, uv);
vec4 previous= texture2D(texture, uv+vec2(-1,0)*pixel);
vec4 next = texture2D(texture, uv+vec2(+1,0)*pixel);
float r = current.r;
float g = current.g;
float b = current.b;
float a = current.a;
if( m <= 0.333 )
{
float z = m/0.333;
r = mix(current.r, previous.b, z);
g = mix(current.g, current.r, z);
b = mix(current.b, current.g, z);
}
else if( m <= 0.666 )
{
float z = (m-0.33)/0.333;
r = mix(previous.b, previous.g, z);
g = mix(current.r, previous.b, z);
b = mix(current.g, current.r, z);
}
else if( m < 1.0 )
{
float z = (m-0.66)/0.334;
r = mix(previous.g, previous.r, z);
g = mix(previous.b, previous.g, z);
b = mix(current.r, previous.b, z);
}
// This would be probably wrong because we do not take into account the
// shifting above.
// vec3 color = energy_distribution(previous, vec4(r,g,b,1), next);
// r = color.r;
// g = color.g;
// b = color.b;
gl_FragColor.rgb = pow( vec3(r,g,b), vec3(1.0/gamma));
}