/*
    Phosphor shader - Copyright (C) 2011 caligari.

    Ported by Hyllian.

   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.

*/

// Parameter lines go here:
// 0.5 = the spot stays inside the original pixel
// 1.0 = the spot bleeds up to the center of next pixel
// #pragma parameter SPOT_WIDTH "CRTCaligari Spot Width" 0.9 0.1 1.5 0.05
// #pragma parameter SPOT_HEIGHT "CRTCaligari Spot Height" 0.75 0.1 1.5 0.05
// Used to counteract the desaturation effect of weighting.
// #pragma parameter COLOR_BOOST "CRTCaligari Color Boost" 1.45 1.0 2.0 0.05
// Constants used with gamma correction.
// #pragma parameter InputGamma "CRTCaligari Input Gamma" 2.4 0.0 5.0 0.1
// #pragma parameter OutputGamma "CRTCaligari Output Gamma" 2.2 0.0 5.0 0.1

#if defined(VERTEX)

#if __VERSION__ >= 130
#define COMPAT_VARYING out
#define COMPAT_ATTRIBUTE in
#define COMPAT_TEXTURE texture
#else
#define COMPAT_VARYING varying
#define COMPAT_ATTRIBUTE attribute
#define COMPAT_TEXTURE texture2D
#endif

#ifdef GL_ES
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

COMPAT_ATTRIBUTE vec4 VertexCoord;
COMPAT_ATTRIBUTE vec4 COLOR;
COMPAT_ATTRIBUTE vec4 TexCoord;
COMPAT_VARYING vec4 COL0;
COMPAT_VARYING vec4 TEX0;
COMPAT_VARYING vec2 onex;
COMPAT_VARYING vec2 oney;

vec4 _oPosition1;
uniform mat4 MVPMatrix;
uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;

#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize

void main()
{
   gl_Position = MVPMatrix * gl_Vertex;
//   gl_Position = MVPMatrix * VertexCoord;
   COL0 = COLOR;
   TEX0.xy = gl_MultiTexCoord0.xy;
//   TEX0.xy = TexCoord.xy;
   onex = vec2(SourceSize.z, 0.0);
   oney = vec2(0.0, SourceSize.w);
}

#elif defined(FRAGMENT)

#if __VERSION__ >= 130
#define COMPAT_VARYING in
#define COMPAT_TEXTURE texture
out vec4 FragColor;
#else
#define COMPAT_VARYING varying
#define FragColor gl_FragColor
#define COMPAT_TEXTURE texture2D
#endif

#ifdef GL_ES
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;
uniform sampler2D Texture;
COMPAT_VARYING vec4 TEX0;
COMPAT_VARYING vec2 onex;
COMPAT_VARYING vec2 oney;

// compatibility #defines
#define Source Texture
#define vTexCoord TEX0.xy

#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
#define OutputSize vec4(OutputSize, 1.0 / OutputSize)

#ifdef PARAMETER_UNIFORM
// All parameter floats need to have COMPAT_PRECISION in front of them
uniform COMPAT_PRECISION float SPOT_WIDTH;
uniform COMPAT_PRECISION float SPOT_HEIGHT;
uniform COMPAT_PRECISION float COLOR_BOOST;
uniform COMPAT_PRECISION float InputGamma;
uniform COMPAT_PRECISION float OutputGamma;
#else
#define SPOT_WIDTH 0.9
#define SPOT_HEIGHT 0.75
#define COLOR_BOOST 1.45
#define InputGamma 2.4
#define OutputGamma 2.2
#endif

#define GAMMA_IN(color)     pow(color,vec4(InputGamma))
#define GAMMA_OUT(color)    pow(color, vec4(1.0 / OutputGamma))

#define TEX2D(coords)	GAMMA_IN( COMPAT_TEXTURE(Source, coords) )

// Macro for weights computing
#define WEIGHT(w) \
   if(w>1.0) w=1.0; \
w = 1.0 - w * w; \
w = w * w;

void main()
{
   vec2 coords = ( vTexCoord * SourceSize.xy );
   vec2 pixel_center = floor( coords ) + vec2(0.5, 0.5);
   vec2 texture_coords = pixel_center * SourceSize.zw;

   vec4 color = TEX2D( texture_coords );

   float dx = coords.x - pixel_center.x;

   float h_weight_00 = dx / SPOT_WIDTH;
   WEIGHT( h_weight_00 );

   color *= vec4( h_weight_00, h_weight_00, h_weight_00, h_weight_00  );

   // get closest horizontal neighbour to blend
   vec2 coords01;
   if (dx>0.0) {
      coords01 = onex;
      dx = 1.0 - dx;
   } else {
      coords01 = -onex;
      dx = 1.0 + dx;
   }
   vec4 colorNB = TEX2D( texture_coords + coords01 );

   float h_weight_01 = dx / SPOT_WIDTH;
   WEIGHT( h_weight_01 );

   color = color + colorNB * vec4( h_weight_01 );

   //////////////////////////////////////////////////////
   // Vertical Blending
   float dy = coords.y - pixel_center.y;
   float v_weight_00 = dy / SPOT_HEIGHT;
   WEIGHT( v_weight_00 );
   color *= vec4( v_weight_00 );

   // get closest vertical neighbour to blend
   vec2 coords10;
   if (dy>0.0) {
      coords10 = oney;
      dy = 1.0 - dy;
   } else {
      coords10 = -oney;
      dy = 1.0 + dy;
   }
   colorNB = TEX2D( texture_coords + coords10 );

   float v_weight_10 = dy / SPOT_HEIGHT;
   WEIGHT( v_weight_10 );

   color = color + colorNB * vec4( v_weight_10 * h_weight_00, v_weight_10 * h_weight_00, v_weight_10 * h_weight_00, v_weight_10 * h_weight_00 );

   colorNB = TEX2D(  texture_coords + coords01 + coords10 );

   color = color + colorNB * vec4( v_weight_10 * h_weight_01, v_weight_10 * h_weight_01, v_weight_10 * h_weight_01, v_weight_10 * h_weight_01 );

   color *= vec4( COLOR_BOOST );

   FragColor = clamp( GAMMA_OUT(color), 0.0, 1.0 );
}
#endif