megazeux/assets/glsl/scalers/emboss.frag

/* MegaZeux
 *
 * Copyright (C) 2008 Joel Bouchard Lamontagne <logicow@gmail.com>
 * Copyright (C) 2009 Alistair John Strachan <alistair@devzero.co.uk>
 * Copyright (C) 2017 Dr Lancer-X <drlancer@megazeux.org>
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#version 110

uniform sampler2D baseMap;

varying vec2 vTexcoord;

void main( void )
{
  vec2 pos = vec2(vTexcoord.x, vTexcoord.y);
  vec2 posA = vec2(vTexcoord.x - 0.0005, vTexcoord.y + 0.0007);
  vec2 posB = vec2(vTexcoord.x + 0.0006, vTexcoord.y - 0.001);

  gl_FragColor =
   texture2D(baseMap, pos) * 2.0 -
   texture2D(baseMap, posA) * 2.0 +
   texture2D(baseMap, posB);
}