#version 120
#extension GL_EXT_gpu_shader4 : enable

#include "lib/settings.glsl"

#include "lib/res_params.glsl"
flat varying vec3 ambientUp;
flat varying vec3 ambientLeft;
flat varying vec3 ambientRight;
flat varying vec3 ambientB;
flat varying vec3 ambientF;
flat varying vec3 ambientDown;
flat varying vec3 zenithColor;
flat varying vec3 sunColor;
flat varying vec3 sunColorCloud;
flat varying vec3 moonColor;
flat varying vec3 moonColorCloud;
flat varying vec3 lightSourceColor;
flat varying vec3 avgSky;
flat varying vec2 tempOffsets;
flat varying float exposure;
flat varying float avgBrightness;
flat varying float exposureF;
flat varying float rodExposure;
flat varying float fogAmount;
flat varying float VFAmount;
flat varying float avgL2;
flat varying float centerDepth;

uniform sampler2D colortex4;
uniform sampler2D colortex6;
uniform sampler2D depthtex0;


flat varying vec3 WsunVec;
uniform mat4 gbufferModelViewInverse;
uniform vec3 sunPosition;
uniform vec2 texelSize;
uniform float rainStrength;
uniform float sunElevation;
uniform float nightVision;
uniform float near;
uniform float far;
uniform float frameTime;
uniform float eyeAltitude;
uniform int frameCounter;
uniform int worldTime;
vec3 sunVec = normalize(mat3(gbufferModelViewInverse) *sunPosition);



#include "lib/sky_gradient.glsl"
#include "/lib/util.glsl"
#include "/lib/ROBOBO_sky.glsl"


vec3 rodSample(vec2 Xi)
{
	float r = sqrt(1.0f - Xi.x*Xi.y);
    float phi = 2 * 3.14159265359 * Xi.y;

    return normalize(vec3(cos(phi) * r, sin(phi) * r, Xi.x)).xzy;
}
vec3 cosineHemisphereSample(vec2 Xi)
{
    float r = sqrt(Xi.x);
    float theta = 2.0 * 3.14159265359 * Xi.y;

    float x = r * cos(theta);
    float y = r * sin(theta);

    return vec3(x, y, sqrt(clamp(1.0 - Xi.x,0.,1.)));
}

float luma(vec3 color) {
	return dot(color,vec3(0.21, 0.72, 0.07));
}

vec2 tapLocation(int sampleNumber,int nb, float nbRot,float jitter)
{
    float alpha = float(sampleNumber+jitter)/nb;
    float angle = (jitter+alpha) * (nbRot * 6.28);

    float ssR = alpha;
    float sin_v, cos_v;

	sin_v = sin(angle);
	cos_v = cos(angle);

    return vec2(cos_v, sin_v)*ssR;
}
//Low discrepancy 2D sequence, integration error is as low as sobol but easier to compute : http://extremelearning.com.au/unreasonable-effectiveness-of-quasirandom-sequences/
vec2 R2_samples(int n){
	vec2 alpha = vec2(0.75487765, 0.56984026);
	return fract(alpha * n);
}
float tanh(float x){
	return (exp(x) - exp(-x))/(exp(x) + exp(-x));
}
float ld(float depth) {
    return (2.0 * near) / (far + near - depth * (far - near));		// (-depth * (far - near)) = (2.0 * near)/ld - far - near
}
void main() {

	gl_Position = ftransform()*0.5+0.5;
	gl_Position.xy = gl_Position.xy*vec2(18.+258*2,258.)*texelSize;
	gl_Position.xy = gl_Position.xy*2.-1.0;

	tempOffsets = R2_samples(frameCounter%10000);

	ambientUp = vec3(0.0);
	ambientDown = vec3(0.0);
	ambientLeft = vec3(0.0);
	ambientRight = vec3(0.0);
	ambientB = vec3(0.0);
	ambientF = vec3(0.0);
	avgSky = vec3(0.0);
	//Integrate sky light for each block side
	int maxIT = 20;
	for (int i = 0; i < maxIT; i++) {
			vec2 ij = R2_samples((frameCounter%1000)*maxIT+i);
			vec3 pos = normalize(rodSample(ij));


			vec3 samplee = 1.72*skyFromTex(pos,colortex4).rgb/maxIT/150.;
			avgSky += samplee/1.72;
			ambientUp += samplee*(pos.y+abs(pos.x)/7.+abs(pos.z)/7.);
			ambientLeft += samplee*(clamp(-pos.x,0.0,1.0)+clamp(pos.y/7.,0.0,1.0)+abs(pos.z)/7.);
			ambientRight += samplee*(clamp(pos.x,0.0,1.0)+clamp(pos.y/7.,0.0,1.0)+abs(pos.z)/7.);
			ambientB += samplee*(clamp(pos.z,0.0,1.0)+abs(pos.x)/7.+clamp(pos.y/7.,0.0,1.0));
			ambientF += samplee*(clamp(-pos.z,0.0,1.0)+abs(pos.x)/7.+clamp(pos.y/7.,0.0,1.0));
			ambientDown += samplee*(clamp(pos.y/6.,0.0,1.0)+abs(pos.x)/7.+abs(pos.z)/7.);

			/*
			ambientUp += samplee*(pos.y);
			ambientLeft += samplee*(clamp(-pos.x,0.0,1.0));
			ambientRight += samplee*(clamp(pos.x,0.0,1.0));
			ambientB += samplee*(clamp(pos.z,0.0,1.0));
			ambientF += samplee*(clamp(-pos.z,0.0,1.0));
			ambientDown += samplee*(clamp(pos.y/6.,0.0,1.0))*0;
			*/

	}


	vec2 planetSphere = vec2(0.0);
	vec3 sky = vec3(0.0);
	vec3 skyAbsorb = vec3(0.0);

	float sunVis = clamp(sunElevation,0.0,0.05)/0.05*clamp(sunElevation,0.0,0.05)/0.05;
	float moonVis = clamp(-sunElevation,0.0,0.05)/0.05*clamp(-sunElevation,0.0,0.05)/0.05;

	zenithColor = calculateAtmosphere(vec3(0.0), vec3(0.0,1.0,0.0), vec3(0.0,1.0,0.0), sunVec, -sunVec, planetSphere, skyAbsorb, 25,tempOffsets.x);
	skyAbsorb = vec3(0.0);
	vec3 absorb = vec3(0.0);
	sunColor = calculateAtmosphere(vec3(0.0), sunVec, vec3(0.0,1.0,0.0), sunVec, -sunVec, planetSphere, skyAbsorb, 25,0.0);
	sunColor = sunColorBase/4000. * skyAbsorb;

	skyAbsorb = vec3(1.0);
	float dSun = 0.03;
	vec3 modSunVec = sunVec*(1.0-dSun)+vec3(0.0,dSun,0.0);
	vec3 modSunVec2 = sunVec*(1.0-dSun)+vec3(0.0,dSun,0.0);
	if (modSunVec2.y > modSunVec.y) modSunVec = modSunVec2;
	sunColorCloud = calculateAtmosphere(vec3(0.0), modSunVec, vec3(0.0,1.0,0.0), sunVec, -sunVec, planetSphere, skyAbsorb, 25,0.);
	sunColorCloud = sunColorBase/4000. * skyAbsorb ;

	skyAbsorb = vec3(1.0);
	moonColor = calculateAtmosphere(vec3(0.0), -sunVec, vec3(0.0,1.0,0.0), sunVec, -sunVec, planetSphere, skyAbsorb, 25,0.5);
	moonColor = moonColorBase/4000.0*skyAbsorb;

	skyAbsorb = vec3(1.0);
	modSunVec = -sunVec*(1.0-dSun)+vec3(0.0,dSun,0.0);
	modSunVec2 = -sunVec*(1.0-dSun)+vec3(0.0,dSun,0.0);
	if (modSunVec2.y > modSunVec.y) modSunVec = modSunVec2;
	moonColorCloud = calculateAtmosphere(vec3(0.0), modSunVec, vec3(0.0,1.0,0.0), sunVec, -sunVec, planetSphere, skyAbsorb, 25,0.5);

	moonColorCloud = moonColorBase/4000.0*0.55;
	// #ifndef CLOUDS_SHADOWS
	// 	sunColor *= (1.0-rainStrength*vec3(0.96,0.95,0.94));
	// 	moonColor *= (1.0-rainStrength*vec3(0.96,0.95,0.94));
	// #endif
	lightSourceColor = sunVis >= 1e-5 ? sunColor * sunVis : moonColor * moonVis;

	float lightDir = float( sunVis >= 1e-5)*2.0-1.0;


	//Fake bounced sunlight
	vec3 bouncedSun = lightSourceColor*0.1/5.0*0.5*clamp(lightDir*sunVec.y,0.0,1.0)*clamp(lightDir*sunVec.y,0.0,1.0);
	vec3 cloudAmbientSun = (sunColorCloud)*0.007;
	vec3 cloudAmbientMoon = (moonColorCloud)*0.007;
	ambientUp += bouncedSun*clamp(-lightDir*sunVec.y+4.,0.,4.0) + cloudAmbientSun*clamp(sunVec.y+2.,0.,4.0) + cloudAmbientMoon*clamp(-sunVec.y+2.,0.,4.0);
	ambientLeft += bouncedSun*clamp(lightDir*sunVec.x+4.,0.0,4.) + cloudAmbientSun*clamp(-sunVec.x+2.,0.0,4.)*0.7 + cloudAmbientMoon*clamp(sunVec.x+2.,0.0,4.)*0.7;
	ambientRight += bouncedSun*clamp(-lightDir*sunVec.x+4.,0.0,4.) + cloudAmbientSun*clamp(sunVec.x+2.,0.0,4.)*0.7 + cloudAmbientMoon*clamp(-sunVec.x+2.,0.0,4.)*0.7;
	ambientB += bouncedSun*clamp(-lightDir*sunVec.z+4.,0.0,4.) + cloudAmbientSun*clamp(sunVec.z+2.,0.0,4.)*0.7 + cloudAmbientMoon*clamp(-sunVec.z+2.,0.0,4.)*0.7;
	ambientF += bouncedSun*clamp(lightDir*sunVec.z+4.,0.0,4.) + cloudAmbientSun*clamp(-sunVec.z+2.,0.0,4.)*0.7 + cloudAmbientMoon*clamp(sunVec.z+2.,0.0,4.)*0.7;
	ambientDown += bouncedSun*clamp(lightDir*sunVec.y+4.,0.0,4.)*0.7 + cloudAmbientSun*clamp(-sunVec.y+2.,0.0,4.)*0.5 + cloudAmbientMoon*clamp(sunVec.y+2.,0.0,4.)*0.5;
	avgSky += bouncedSun*5.;

	vec3 rainNightBoost = moonColorCloud*rainStrength*0.005;
	ambientUp += rainNightBoost;
	ambientLeft += rainNightBoost;
	ambientRight += rainNightBoost;
	ambientB += rainNightBoost;
	ambientF += rainNightBoost;
	ambientDown += rainNightBoost;
	avgSky += rainNightBoost;

	float avgLuma = 0.0;
	float m2 = 0.0;
	int n=100;
	vec2 clampedRes = max(1.0/texelSize,vec2(1920.0,1080.));
	float avgExp = 0.0;
	float avgB = 0.0;
	vec2 resScale = vec2(1920.,1080.)/clampedRes*BLOOM_QUALITY;
	const int maxITexp = 50;
	float w = 0.0;
	for (int i = 0; i < maxITexp; i++){
			vec2 ij = R2_samples((frameCounter%2000)*maxITexp+i);
			vec2 tc = 0.5 + (ij-0.5) * 0.7;
			vec3 sp = texture2D(colortex6,tc/16. * resScale+vec2(0.375*resScale.x+4.5*texelSize.x,.0)).rgb;
			avgExp += log(luma(sp));
			avgB += log(min(dot(sp,vec3(0.07,0.22,0.71)),8e-2));
	}

	avgExp = exp(avgExp/maxITexp);
	avgB = exp(avgB/maxITexp);

	avgBrightness = clamp(mix(avgExp,texelFetch2D(colortex4,ivec2(10,37),0).g,0.95),0.00003051757,65000.0);

	float L = max(avgBrightness,1e-8);
	float keyVal = 1.03-2.0/(log(L*4000/150.*8./3.0+1.0)/log(10.0)+2.0);
	float expFunc = 0.5+0.5*tanh(log(L));
	float targetExposure = 0.18/log2(L*2.5+1.045)*0.62;

	avgL2 = clamp(mix(avgB,texelFetch2D(colortex4,ivec2(10,37),0).b,0.985),0.00003051757,65000.0);
	float targetrodExposure = max(0.012/log2(avgL2+1.002)-0.1,0.0)*1.2;


	exposure=max(targetExposure*EXPOSURE_MULTIPLIER, 0);
	float currCenterDepth = ld(texture2D(depthtex0, vec2(0.5)*RENDER_SCALE).r);
	centerDepth = mix(sqrt(texelFetch2D(colortex4,ivec2(14,37),0).g/65000.0), currCenterDepth, clamp(DoF_Adaptation_Speed*exp(-0.016/frameTime+1.0)/(6.0+currCenterDepth*far),0.0,1.0));
	centerDepth = centerDepth * centerDepth * 65000.0;

	rodExposure = targetrodExposure;

	#ifndef AUTO_EXPOSURE
	 exposure = Manual_exposure_value;
	 rodExposure = clamp(log(Manual_exposure_value*2.0+1.0)-0.1,0.0,2.0);
	#endif
}