/*
   The 4xGLSoft shader
   
   Copyright (C) 2005 guest(r) - guest.r@gmail.com

   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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/


uniform sampler2D OGL2Texture;


const mat3 RGBtoYIQ = mat3(0.299, 0.596, 0.212, 
                           0.587,-0.275,-0.523, 
                           0.114,-0.321, 0.311);

const mat3 YIQtoRGB = mat3(1.0, 1.0, 1.0,
                           0.95568806036115671171,-0.27158179694405859326,-1.1081773266826619523,
                           0.61985809445637075388,-0.64687381613840131330, 1.7050645599191817149);

// intensity (1.2 = more deep)
const vec3 val00 = vec3( 1.15, 1.15, 1.15);
//const vec3 val00 = vec3( 1.2, 1.2, 1.2);

void main()
{
	vec3 c11 = texture2D(OGL2Texture, gl_TexCoord[0].xy).xyz;
	vec3 s00 = texture2D(OGL2Texture, gl_TexCoord[1].xy).xyz; 
	vec3 s20 = texture2D(OGL2Texture, gl_TexCoord[2].xy).xyz; 
	vec3 s22 = texture2D(OGL2Texture, gl_TexCoord[3].xy).xyz; 
	vec3 s02 = texture2D(OGL2Texture, gl_TexCoord[4].xy).xyz; 
	vec3 c00 = texture2D(OGL2Texture, gl_TexCoord[5].xy).xyz; 
	vec3 c22 = texture2D(OGL2Texture, gl_TexCoord[6].xy).xyz; 
	vec3 c20 = texture2D(OGL2Texture, gl_TexCoord[5].zw).xyz;
	vec3 c02 = texture2D(OGL2Texture, gl_TexCoord[6].zw).xyz;
	vec3 c01 = texture2D(OGL2Texture, gl_TexCoord[1].zw).xyz; 
	vec3 c21 = texture2D(OGL2Texture, gl_TexCoord[2].zw).xyz; 
	vec3 c10 = texture2D(OGL2Texture, gl_TexCoord[3].zw).xyz; 
	vec3 c12 = texture2D(OGL2Texture, gl_TexCoord[4].zw).xyz;  
	vec3 dt = vec3(1.0,1.0,1.0);

	float d1=dot(abs(c00-c22),dt)+0.001;
	float d2=dot(abs(c20-c02),dt)+0.001;
	float hl=dot(abs(c01-c21),dt)+0.001;
	float vl=dot(abs(c10-c12),dt)+0.001;
	float m1=dot(abs(s00-s22),dt)+0.001;
	float m2=dot(abs(s02-s20),dt)+0.001;

	vec3 t1=(hl*(c10+c12)+vl*(c01+c21)+(hl+vl)*c11)/(3.0*(hl+vl));
	vec3 t2=(d1*(c20+c02)+d2*(c00+c22)+(d1+d2)*c11)/(3.0*(d1+d2));

	vec3 c0 =.255*(t1+t2+(m2*(s00+s22)+m1*(s02+s20))/(m1+m2));
	vec3 c1=RGBtoYIQ*c0;
	c1=vec3(pow(c1.x,val00.x),c1.yz*val00.yz);
	gl_FragColor.xyz=YIQtoRGB*c1;

// original algorithm
//	gl_FragColor.xyz=.25*(t1+t2+(m2*(s00+s22)+m1*(s02+s20))/(m1+m2));
}