#pragma once

#include "CoreMinimal.h"

/** Constants of the look (Render/*; DESIGN_UE.md section 7, requirements V1, U6, U12). Lengths in metres unless the name says uu. */
namespace Descent::Tune::Look
{
	// ---- surface light and fog density (sections 2.7, 7.1) ----
	/** L(Z) = clamp(exp(-(SurfaceZ - Z) / SurfaceScaleM), 0, 1). */
	constexpr double SurfaceZ = 40.0;
	constexpr double SurfaceScaleM = 68.0;
	/** rho = FogBase + FogLightGain * (1 - L). */
	constexpr double FogBase = 0.015;
	constexpr double FogLightGain = 0.006;
	constexpr double FogHelmFactor = 0.3;       // helm camera views 1-4 (v2)
	/** Absorption per colour channel: red dies first (section 7.2). */
	constexpr double AbsorbR = 3.2, AbsorbG = 1.05, AbsorbB = 0.8;
	constexpr double FogPower = 1.35;
	constexpr double FarMetres = 1500.0;        // sky pixels count as this far
	constexpr double WaterColorMinLight = 0.03; // water colour * (0.03 + 0.97 L)
	constexpr double SunGlowGain = 0.35;
	constexpr double SunGlowPower = 6.0;

	// Linear water colours (sRGB #2f8f9a, #06222a).
	constexpr float WaterTopR = 0.028f, WaterTopG = 0.275f, WaterTopB = 0.323f;
	constexpr float WaterDeepR = 0.0018f, WaterDeepG = 0.0159f, WaterDeepB = 0.0232f;
	constexpr float SunDirX = -0.12f, SunDirY = 0.20f, SunDirZ = 1.0f;

	// ---- ambient (section 7.3) ----
	constexpr float AmbientSkyR = 0.35f, AmbientSkyG = 0.62f, AmbientSkyB = 0.66f;
	constexpr float AmbientGroundR = 0.03f, AmbientGroundG = 0.05f, AmbientGroundB = 0.06f;
	constexpr double AmbientBase = 0.015, AmbientLightGain = 1.25;
	constexpr float AmbientDryR = 0.95f, AmbientDryG = 0.90f, AmbientDryB = 0.82f;
	constexpr double AmbientDryLevel = 0.06;

	// ---- exponential height fog, volumetric only (section 7.2) ----
	constexpr float VolFogDensity = 0.02f;
	constexpr float VolFogHeightFalloff = 0.001f;
	constexpr float VolFogExtinctionScale = 4.0f;
	constexpr float VolFogScatteringDistribution = 0.2f;
	constexpr float VolFogDistanceUU = 12000.f;
	constexpr float VolFogStartSwimUU = 50.f;
	constexpr float VolFogStartCockpitUU = 200.f;
	constexpr double VolFogBlendSec = 0.3;      // switching it off in the dry (section 7.4)

	// ---- lights (section 7.5): bUseInverseSquaredFalloff = false, LightFalloffExponent 3 ----
	constexpr float LightFalloffExponent = 3.f;
	constexpr double TenderLampRadiusM = 90.0, TenderLampInnerDeg = 14.5, TenderLampOuterDeg = 26.4, TenderLampIntensity = 3.2, TenderLampScatter = 1.0;
	constexpr double FlashlightRadiusM = 55.0, FlashlightInnerDeg = 12.0, FlashlightOuterDeg = 20.6, FlashlightIntensity = 2.0, FlashlightScatter = 0.8;
	constexpr double SunIntensityPerLight = 1.6;   // surface sun = this * L
	constexpr double SunHiddenBelowL = 0.02;
	constexpr double SunVolScatter = 1.0;
	constexpr int32 LightPoolSize = 24;
	constexpr double LightPoolMaxScore = 9.0;      // keep a request only if distance^2 / radius^2 - priority < this
	constexpr double LightPoolScatter = 0.3;

	// ---- post process (section 7.6) ----
	constexpr float ExposureEvDefault = 0.3f;     // cvar descent.Look.ExposureEV; chosen from look_sweep so the three wall bands are all mid-band
	constexpr float BloomIntensity = 0.15f;        // x cvar descent.Look.Bloom (U12)
	constexpr float BloomThreshold = 1.2f;
	constexpr float BloomSizeScale = 2.0f;
	constexpr float VignetteIntensity = 0.45f;
	constexpr float FilmGrainIntensity = 0.15f;
	constexpr float SceneFringeIntensity = 0.2f;
	constexpr float AoIntensity = 0.5f;
	constexpr float AoRadiusUU = 60.f;

	// ---- marine snow (section 7.7) ----
	constexpr int32 SnowInstances = 3200;
	constexpr int32 SnowInstancesLow = 1500;
	constexpr double SnowCubeM = 40.0;

	// ---- stencil value of the dry interior (sections 3.2, 7.4) ----
	constexpr int32 DryStencilValue = 1;

	// ---- luminance bands the look scenarios check (section 7.10), sRGB-encoded luma 0..1 ----
	constexpr double CalibWall10Lo = 0.38, CalibWall10Hi = 0.50;
	constexpr double CalibWall20Lo = 0.25, CalibWall20Hi = 0.40;
	constexpr double CalibWall40Lo = 0.06, CalibWall40Hi = 0.18;
	constexpr double DeepLampLo = 0.06, DeepLampHi = 0.35;
	constexpr double DeepDarkMax = 0.03;
	constexpr double NearWallMax = 0.55;
	constexpr double ThroatLo = 0.05, ThroatHi = 0.25;
	constexpr double BloomRingMaxFraction = 0.04, BloomOffRingMaxFraction = 0.01;
}