// MinecraftPT — Final_FS
// HDR tonemapping, color grading, dithering, and output to screen.

#include "/Lib/Settings.glsl"
#include "/Lib/Utilities.glsl"
#include "/Lib/BasicFunctions/TemporalNoise.glsl"

uniform sampler2D exposureTex;

#if defined PROGRAM_FINAL_0
layout(location = 0) out vec4 colorOut;
#elif defined PROGRAM_FINAL_1
layout(location = 0) out vec4 colorOut;
#endif

// Tonemapping operators
vec3 TonemapACES(vec3 color){
	// ACES filmic
	float a = 2.51;
	float b = 0.03;
	float c = 2.43;
	float d = 0.59;
	float e = 0.14;
	return saturate((color * (a * color + b)) / (color * (c * color + d) + e));
}

vec3 TonemapAGX(vec3 color){
	// AGX-inspired: log-shaping curve
	vec3 logColor = log2(max(color, 1e-6));
	vec3 mid = vec3(AGX_HDR_MIDGREY);
	vec3 shaped = logColor - mid;
	shaped = tanh(shaped * 0.5) * 0.5 + 0.5;
	vec3 result = exp2(shaped + mid);
	return result;
}

vec3 TonemapFilmic(vec3 color){
	// Uncharted 2 filmic
	vec3 x = max(color, 0.0);
	return (x * (6.2 * x + 0.5)) / (x * (6.2 * x + 1.7) + 0.06);
}

// Color grading
vec3 ApplyColorGrading(vec3 color){
	// White/black point
	color = (color - BLACK_POINT) / (WHITE_POINT - BLACK_POINT + 1e-6);

	// Saturation
	float lum = luminance(color);
	color = mix(vec3(lum), color, SATURATION);

	// Gamma
	color = pow(color, vec3(GAMMA));

	// Hue shifts (simplified)
	#ifdef ADVANCED_COLOR
		vec3 midtone = color * MIDTONE_HUE * MIDTONE_STRENGTH;
		vec3 highlight = color * HIGHLIGHT_HUE * HIGHLIGHT_STRENGTH;
		vec3 shadow = color * SHADOW_HUE * SHADOW_STRENGTH;
		color += midtone + highlight + shadow;
	#endif

	return color;
}

void main(){
	vec3 color = texelFetch(colortex12, ivec2(gl_FragCoord.xy), 0).rgb;

	// Exposure
	#ifdef MANUAL_EXPOSURE
		float exposure = MANUAL_EXPOSURE * pow(2.0, EV_VALUE);
	#else
		float exposure = textureLod(exposureTex, vec2(0.5), 0.0).r;
	#endif
	color *= exposure;

	// Bloom composite
	#ifdef BLOOM
		vec3 bloom = vec3(0.0);
		// Simple bloom: sample from bloom buffer
		bloom = textureLod(colortex15, gl_FragCoord.xy / screenSize, 0.0).rgb;
		color += bloom * BLOOM_AMOUNT;
	#endif

	// Tonemapping
	#if TONEMAP_OPERATOR == 0
		color = TonemapACES(color);
	#elif TONEMAP_OPERATOR == 1
		color = TonemapAGX(color);
	#elif TONEMAP_OPERATOR == 2
		color = TonemapFilmic(color);
	#else
		// Vanilla-like: Reinhard
		color = color / (color + 1.0);
	#endif

	// Color grading
	color = ApplyColorGrading(color);

	// Dithering
	vec2 noise = BlueNoiseTemporal2();
	color += (noise - 0.5) / 255.0;

	// Gamma correction
	color = LinearToGamma(color);

	colorOut = vec4(color, 1.0);
}