#version 450

/*
    Copyright (C) 2016 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.
*/

layout(push_constant) uniform Push
{
    vec4 OutputSize;
    vec4 OriginalSize;
    vec4 SourceSize;
    float AAOFFSET;
} params;

layout(std140, set = 0, binding = 0) uniform UBO
{
    mat4 MVP;
} global;

#pragma parameter AAOFFSET "Filter width" 1.0 0.25 2.0 0.125

#define AAOFFSET  params.AAOFFSET

#pragma stage vertex
layout(location = 0) in  vec4 Position;
layout(location = 1) in  vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;

/*    VERTEX_SHADER    */
void main()
{
    gl_Position = global.MVP * Position;
    vTexCoord   = TexCoord;
}

#pragma stage fragment
layout(location = 0) in  vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;

void main()
{
   vec2 texsize = params.SourceSize.xy;
   float dx = AAOFFSET/texsize.x;
   float dy = AAOFFSET/texsize.y;
   vec3 dt = vec3(1.0, 1.0, 1.0);
 
   vec4 yx = vec4( dx, dy, -dx, -dy);
   vec4 xh = yx*vec4(3.0,1.0,3.0,1.0);
   vec4 yv = yx*vec4(1.0,3.0,1.0,3.0);

   vec3 c11 = texture(Source, vTexCoord        ).xyz; 	
   vec3 s00 = texture(Source, vTexCoord + yx.zw).xyz; 
   vec3 s20 = texture(Source, vTexCoord + yx.xw).xyz; 
   vec3 s22 = texture(Source, vTexCoord + yx.xy).xyz; 
   vec3 s02 = texture(Source, vTexCoord + yx.zy).xyz;
   vec3 h00 = texture(Source, vTexCoord + xh.zw).xyz; 
   vec3 h20 = texture(Source, vTexCoord + xh.xw).xyz; 
   vec3 h22 = texture(Source, vTexCoord + xh.xy).xyz; 
   vec3 h02 = texture(Source, vTexCoord + xh.zy).xyz;
   vec3 v00 = texture(Source, vTexCoord + yv.zw).xyz; 
   vec3 v20 = texture(Source, vTexCoord + yv.xw).xyz; 
   vec3 v22 = texture(Source, vTexCoord + yv.xy).xyz; 
   vec3 v02 = texture(Source, vTexCoord + yv.zy).xyz;	 
   
   float m1=1.0/(dot(abs(s00-s22),dt)+0.00001);
   float m2=1.0/(dot(abs(s02-s20),dt)+0.00001);
   float h1=1.0/(dot(abs(s00-h22),dt)+0.00001);
   float h2=1.0/(dot(abs(s02-h20),dt)+0.00001);
   float h3=1.0/(dot(abs(h00-s22),dt)+0.00001);
   float h4=1.0/(dot(abs(h02-s20),dt)+0.00001);
   float v1=1.0/(dot(abs(s00-v22),dt)+0.00001);
   float v2=1.0/(dot(abs(s02-v20),dt)+0.00001);
   float v3=1.0/(dot(abs(v00-s22),dt)+0.00001);
   float v4=1.0/(dot(abs(v02-s20),dt)+0.00001);

   vec3 t1 = 0.5*(m1*(s00+s22)+m2*(s02+s20))/(m1+m2);
   vec3 t2 = 0.5*(h1*(s00+h22)+h2*(s02+h20)+h3*(h00+s22)+h4*(h02+s20))/(h1+h2+h3+h4);
   vec3 t3 = 0.5*(v1*(s00+v22)+v2*(s02+v20)+v3*(v00+s22)+v4*(v02+s20))/(v1+v2+v3+v4);

   float k1 = 1.0/(dot(abs(t1-c11),dt)+0.00001);
   float k2 = 1.0/(dot(abs(t2-c11),dt)+0.00001);
   float k3 = 1.0/(dot(abs(t3-c11),dt)+0.00001);

   FragColor = vec4((k1*t1 + k2*t2 + k3*t3)/(k1+k2+k3),1.0);
}
