// SPDX-FileCopyrightText: 2002-2026 PCSX2 Dev Team
// SPDX-License-Identifier: GPL-3.0+

//#version 420 // Keep it for editor detection

#ifdef VERTEX_SHADER

layout(location = 0) in vec4 a_pos;
layout(location = 1) in vec2 a_tex;

layout(location = 0) out vec2 v_tex;

void main()
{
	gl_Position = vec4(a_pos.x, -a_pos.y, a_pos.z, a_pos.w);
	v_tex = a_tex;
}

#endif

/*
** Contrast, saturation, brightness
** Code of this function is from TGM's shader pack
** http://irrlicht.sourceforge.net/phpBB2/viewtopic.php?t=21057
** TGM's author comment about the license (included in the previous link)
** "do with it, what you want! its total free!
** (but would be nice, if you say that you used my shaders  :wink: ) but not necessary"
*/

#ifdef FRAGMENT_SHADER

layout(push_constant) uniform cb0
{
	vec4 params;
};

layout(set = 0, binding = 0) uniform sampler2D samp0;
layout(location = 0) in vec2 v_tex;
layout(location = 0) out vec4 o_col0;

// For all settings: 1.0 = 100% 0.5=50% 1.5 = 150%
vec4 ContrastSaturationBrightness(vec4 color)
{
    float brt = params.x;
    float con = params.y;
    float sat = params.z;
    float gam = params.w;

    // Increase or decrease these values to adjust r, g and b color channels separately
    const float AvgLumR = 0.5;
    const float AvgLumG = 0.5;
    const float AvgLumB = 0.5;

    const vec3 LumCoeff = vec3(0.2125, 0.7154, 0.0721);

    vec3 AvgLumin = vec3(AvgLumR, AvgLumG, AvgLumB);
    vec3 brtColor = color.rgb * brt;
    float dot_intensity = dot(brtColor, LumCoeff);
    vec3 intensity = vec3(dot_intensity, dot_intensity, dot_intensity);
    vec3 satColor = mix(intensity, brtColor, sat);
    vec3 conColor = mix(AvgLumin, satColor, con);

    vec3 csb = conColor;
    csb = pow(csb, vec3(1.0 / gam));
    color.rgb = csb;
    return color;
}


void main()
{
    vec4 c = texture(samp0, v_tex);
    o_col0 = ContrastSaturationBrightness(c);
}


#endif
