/*
   Hyllian's CRT Shader
  
   Copyright (C) 2011-2020 Hyllian - sergiogdb@gmail.com

   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to deal
   in the Software without restriction, including without limitation the rights
   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:

   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   THE SOFTWARE.

*/

#version 120

#pragma parameter BEAM_PROFILE "BEAM PROFILE (BP)" 0.0 0.0 6.0 1.0
#pragma parameter BEAM_MIN_WIDTH "  Custom [If   BP=0.00] MIN BEAM WIDTH" 0.86 0.0 1.0 0.02
#pragma parameter BEAM_MAX_WIDTH "  Custom [If   BP=0.00] MAX BEAM WIDTH" 1.0 0.0 1.0 0.02
#pragma parameter SCANLINES_STRENGTH "  Custom [If   BP=0.00] SCANLINES STRENGTH" 0.58 0.0 1.0 0.02
#pragma parameter COLOR_BOOST "  Custom [If   BP=0.00] COLOR BOOST" 1.25 1.0 2.0 0.05
#pragma parameter HFILTER_SHARPNESS "HORIZONTAL FILTER SHARPNESS" 1.0 0.0 1.0 0.02
#pragma parameter CRT_ANTI_RINGING "ANTI RINGING" 1.0 0.0 1.0 0.1
#pragma parameter InputGamma "INPUT GAMMA" 2.4 0.0 5.0 0.1
#pragma parameter OutputGamma "OUTPUT GAMMA" 2.2 0.0 5.0 0.1
#pragma parameter VSCANLINES "SCANLINES DIRECTION" 0.0 0.0 1.0 1.0

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


#define texCoord TEX0

#if defined(VERTEX)

#if __VERSION__ >= 130
#define OUT out
#define IN  in
#define tex2D texture
#else
#define OUT varying 
#define IN attribute 
#define tex2D texture2D
#endif

#ifdef GL_ES
#define PRECISION mediump
#else
#define PRECISION
#endif


IN  vec4 VertexCoord;
IN  vec4 Color;
IN  vec2 TexCoord;
OUT vec4 color;
OUT vec2 texCoord;

uniform mat4 MVPMatrix;
uniform PRECISION int FrameDirection;
uniform PRECISION int FrameCount;
uniform PRECISION vec2 OutputSize;
uniform PRECISION vec2 TextureSize;
uniform PRECISION vec2 InputSize;

void main()
{
    gl_Position = MVPMatrix * VertexCoord;
    color = Color;
    texCoord = TexCoord;
}


#elif defined(FRAGMENT)

#if __VERSION__ >= 130
#define IN in
#define tex2D texture
out vec4 FragColor;
#else
#define IN varying
#define FragColor gl_FragColor
#define tex2D texture2D
#endif

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

uniform PRECISION int FrameDirection;
uniform PRECISION int FrameCount;
uniform PRECISION vec2 OutputSize;
uniform PRECISION vec2 TextureSize;
uniform PRECISION vec2 InputSize;
uniform sampler2D s_p;
IN vec2 texCoord;

#ifdef PARAMETER_UNIFORM
uniform PRECISION float BEAM_PROFILE;
uniform PRECISION float BEAM_MIN_WIDTH;
uniform PRECISION float BEAM_MAX_WIDTH;
uniform PRECISION float SCANLINES_STRENGTH;
uniform PRECISION float COLOR_BOOST;
uniform PRECISION float HFILTER_SHARPNESS;
uniform PRECISION float CRT_ANTI_RINGING;
uniform PRECISION float InputGamma;
uniform PRECISION float OutputGamma;
uniform PRECISION float VSCANLINES;
#else
#define BEAM_PROFILE 0.0
#define BEAM_MIN_WIDTH 0.86
#define BEAM_MAX_WIDTH 1.0
#define SCANLINES_STRENGTH 0.58
#define COLOR_BOOST 1.25
#define HFILTER_SHARPNESS 1.0
#define CRT_ANTI_RINGING 1.0
#define InputGamma 2.4
#define OutputGamma 2.2
#define VSCANLINES 0.0 
#endif
// END PARAMETERS //


// Horizontal cubic filter.

// Some known filters use these values:

//    B = 0.0, C = 0.0  =>  Hermite cubic filter.
//    B = 1.0, C = 0.0  =>  Cubic B-Spline filter.
//    B = 0.0, C = 0.5  =>  Catmull-Rom Spline filter. This is the default used in this shader.
//    B = C = 1.0/3.0   =>  Mitchell-Netravali cubic filter.
//    B = 0.3782, C = 0.3109  =>  Robidoux filter.
//    B = 0.2620, C = 0.3690  =>  Robidoux Sharp filter.

float B = 1.0 - HFILTER_SHARPNESS;
float C = HFILTER_SHARPNESS*0.5; // B+2C=1  Mitchel-Netravali recommendation line.  

mat4 invX = mat4(                          (-B - 6.0*C)/6.0,   (12.0 - 9.0*B - 6.0*C)/6.0,  -(12.0 - 9.0*B - 6.0*C)/6.0,   (B + 6.0*C)/6.0,
                                              (3.0*B + 12.0*C)/6.0, (-18.0 + 12.0*B + 6.0*C)/6.0, (18.0 - 15.0*B - 12.0*C)/6.0,                -C,
                                              (-3.0*B - 6.0*C)/6.0,                          0.0,          (3.0*B + 6.0*C)/6.0,               0.0,
                                                             B/6.0,            (6.0 - 2.0*B)/6.0,                        B/6.0,               0.0);



#define scanlines_strength (4.0*profile.x)
#define beam_min_width     profile.y
#define beam_max_width     profile.z
#define color_boost        profile.w

vec4 get_beam_profile()
{
	vec4 bp = vec4(SCANLINES_STRENGTH, BEAM_MIN_WIDTH, BEAM_MAX_WIDTH, COLOR_BOOST);

if (BEAM_PROFILE == 1.0)  bp = vec4(0.40, 1.00, 1.00, 1.00); // Catmull-rom
if (BEAM_PROFILE == 2.0)  bp = vec4(0.72, 1.00, 1.00, 1.25); // Catmull-rom
if (BEAM_PROFILE == 3.0)  bp = vec4(0.60, 0.50, 1.00, 1.25); // Hermite
if (BEAM_PROFILE == 4.0)  bp = vec4(0.60, 0.72, 1.00, 1.25); // Hermite
if (BEAM_PROFILE == 5.0)  bp = vec4(0.68, 0.68, 1.00, 1.25); // Hermite
if (BEAM_PROFILE == 6.0)  bp = vec4(0.70, 0.50, 1.00, 1.80); // Catmull-rom

	return bp;
}




void main()
{
    vec4 profile = get_beam_profile();

    vec2 dx = mix(vec2(1.0/TextureSize.x, 0.0), vec2(0.0, 1.0/TextureSize.y), VSCANLINES);
    vec2 dy = mix(vec2(0.0, 1.0/TextureSize.y), vec2(1.0/TextureSize.x, 0.0), VSCANLINES);

    vec2 pix_coord = texCoord.xy*TextureSize + vec2(-0.5, 0.5);

    vec2 tc = mix((floor(pix_coord) + vec2(0.5, 0.5))/TextureSize, (floor(pix_coord) + vec2(1.0, -0.5))/TextureSize, VSCANLINES);

    vec2 fp = mix(fract(pix_coord), fract(pix_coord.yx), VSCANLINES);

    vec4 c00 = GAMMA_IN(tex2D(s_p, tc     - dx - dy).xyzw);
    vec4 c01 = GAMMA_IN(tex2D(s_p, tc          - dy).xyzw);
    vec4 c02 = GAMMA_IN(tex2D(s_p, tc     + dx - dy).xyzw);
    vec4 c03 = GAMMA_IN(tex2D(s_p, tc + 2.0*dx - dy).xyzw);
    vec4 c10 = GAMMA_IN(tex2D(s_p, tc     - dx).xyzw);
    vec4 c11 = GAMMA_IN(tex2D(s_p, tc         ).xyzw);
    vec4 c12 = GAMMA_IN(tex2D(s_p, tc     + dx).xyzw);
    vec4 c13 = GAMMA_IN(tex2D(s_p, tc + 2.0*dx).xyzw);

    mat4 color_matrix0 = mat4(c00, c01, c02, c03);
    mat4 color_matrix1 = mat4(c10, c11, c12, c13);

    vec4 lobes = vec4(fp.x*fp.x*fp.x, fp.x*fp.x, fp.x, 1.0);

    vec4 invX_Px  = invX * lobes;
    vec4 color0   = color_matrix0 * invX_Px;
    vec4 color1   = color_matrix1 * invX_Px;

    //  Get min/max samples
    vec4 min_sample0 = min(c01,c02);
    vec4 max_sample0 = max(c01,c02);
    vec4 min_sample1 = min(c11,c12);
    vec4 max_sample1 = max(c11,c12);

    // Anti-ringing
    vec4 aux = color0;
    color0 = clamp(color0, min_sample0, max_sample0);
    color0 = mix(aux, color0, CRT_ANTI_RINGING);
    aux = color1;
    color1 = clamp(color1, min_sample1, max_sample1);
    color1 = mix(aux, color1, CRT_ANTI_RINGING);

    float pos0 = fp.y;
    float pos1 = 1.0 - fp.y;

    vec4 lum0 = mix(vec4(beam_min_width), vec4(beam_max_width), color0);
    vec4 lum1 = mix(vec4(beam_min_width), vec4(beam_max_width), color1);

    vec4 d0 = scanlines_strength*pos0/(lum0+0.0000001);
    vec4 d1 = scanlines_strength*pos1/(lum1+0.0000001);

    d0 = exp(-d0*d0);
    d1 = exp(-d1*d1);

    vec4 color = color_boost*(color0*d0+color1*d1);           

    color  = GAMMA_OUT(color);

    FragColor =  vec4(color);
}
#endif
