// MinecraftPT — Sky_Overworld_FS
// Renders the sky into the background (colortex12) where no geometry was drawn.

#include "/Lib/Settings.glsl"
#include "/Lib/Utilities.glsl"
#include "/Lib/BasicFunctions/LightingConstants.glsl"
#include "/Lib/BasicFunctions/PrecomputedAtmosphere.glsl"
#include "/Lib/IndividualFunctions/EndSky.glsl"
#include "/Lib/IndividualFunctions/PlanarClouds.glsl"
#include "/Lib/IndividualFunctions/CloudShadow.glsl"

uniform sampler2D depthtex0;

layout(location = 0) out vec4 colorOut;

void main(){
	ivec2 texelCoord = ivec2(gl_FragCoord.xy);

	float depth = texelFetch(depthtex0, texelCoord, 0).r;
	if (depth < 1.0){
		// Not sky — preserve scene
		discard;
	}

	// Reconstruct view ray
	vec4 viewPos = gbufferProjectionInverse * vec4(vec2(texelCoord) / screenSize * 2.0 - 1.0, 1.0, 1.0);
	vec3 viewDir = normalize(viewPos.xyz / viewPos.w);
	vec3 worldDir = normalize(mat3(gbufferModelViewInverse) * viewDir);

	vec3 sunDir = GetSunDirWorld();

	// Sky radiance
	vec3 color = GetSkyRadiance(worldDir, sunDir);

	#ifdef DIMENSION_END
		color = GetEndSky(worldDir, sunDir);
	#elif defined DIMENSION_NETHER
		// Nether: dark smoky red-brown atmosphere
		color = vec3(0.18, 0.06, 0.03) * 1.2;
		color += vec3(0.5, 0.2, 0.1) * 0.3 * (1.0 - abs(worldDir.y) * 0.5);
	#endif

	// Planar clouds
	#ifdef PLANAR_CLOUDS
		if (PLANAR_CLOUDS > 0){
			// Ray-plane intersection with cloud layer
			float cloudAlt = mix(PC_ALTITUDE, CLOUD_CLEAR_ALTITUDE, wetness * 0.5);
			if (worldDir.y > 0.001){
				float t = (cloudAlt - cameraPosition.y) / worldDir.y;
				if (t > 0.0){
					vec3 cloudPos = cameraPosition + worldDir * t;
					vec3 cloudColor;
					float cloudDensity = GetPlanarCloudDensity(cloudPos.xz, frameTimeCounter * CLOUD_SPEED, cloudColor);

					if (cloudDensity > 0.01){
						// Soft cloud edge
						vec3 cloudLight = mix(GetCloudAtmoIrradiance(), GetCloudSunIrradiance(), 0.8);
						color = mix(color, cloudLight, cloudDensity * 0.8);
					}
				}
			}
		}
	#endif

	colorOut = vec4(color, 1.0);
}