/**
* @file llsettingssky.cpp
* @author optional
* @brief A base class for asset based settings groups.
*
* $LicenseInfo:2011&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2017, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
* $/LicenseInfo$
*/

#include "llsettingssky.h"
#include "indra_constants.h"
#include <algorithm>
#include "lltrace.h"
#include "llfasttimer.h"
#include "v3colorutil.h"

#pragma optimize("", off)

static const F32 NIGHTTIME_ELEVATION     = -8.0f; // degrees
static const F32 NIGHTTIME_ELEVATION_SIN = (F32)sinf(NIGHTTIME_ELEVATION * DEG_TO_RAD);
static const LLVector3 DUE_EAST = LLVector3::x_axis;
//=========================================================================
namespace
{
    LLTrace::BlockTimerStatHandle FTM_BLEND_SKYVALUES("Blending Sky Environment");
    LLTrace::BlockTimerStatHandle FTM_UPDATE_SKYVALUES("Update Sky Environment");    
}

static LLQuaternion convert_azimuth_and_altitude_to_quat(F32 azimuth, F32 altitude)
{
    LLQuaternion quat;
    quat.setEulerAngles(0.0f, -altitude, azimuth);
    return quat;
}

const F32 LLSettingsSky::DOME_OFFSET(0.96f);
const F32 LLSettingsSky::DOME_RADIUS(15000.f);

//=========================================================================
const std::string LLSettingsSky::SETTING_AMBIENT("ambient");
const std::string LLSettingsSky::SETTING_BLUE_DENSITY("blue_density");
const std::string LLSettingsSky::SETTING_BLUE_HORIZON("blue_horizon");
const std::string LLSettingsSky::SETTING_DENSITY_MULTIPLIER("density_multiplier");
const std::string LLSettingsSky::SETTING_DISTANCE_MULTIPLIER("distance_multiplier");
const std::string LLSettingsSky::SETTING_HAZE_DENSITY("haze_density");
const std::string LLSettingsSky::SETTING_HAZE_HORIZON("haze_horizon");

const std::string LLSettingsSky::SETTING_BLOOM_TEXTUREID("bloom_id");
const std::string LLSettingsSky::SETTING_CLOUD_COLOR("cloud_color");
const std::string LLSettingsSky::SETTING_CLOUD_POS_DENSITY1("cloud_pos_density1");
const std::string LLSettingsSky::SETTING_CLOUD_POS_DENSITY2("cloud_pos_density2");
const std::string LLSettingsSky::SETTING_CLOUD_SCALE("cloud_scale");
const std::string LLSettingsSky::SETTING_CLOUD_SCROLL_RATE("cloud_scroll_rate");
const std::string LLSettingsSky::SETTING_CLOUD_SHADOW("cloud_shadow");
const std::string LLSettingsSky::SETTING_CLOUD_TEXTUREID("cloud_id");

const std::string LLSettingsSky::SETTING_DOME_OFFSET("dome_offset");
const std::string LLSettingsSky::SETTING_DOME_RADIUS("dome_radius");
const std::string LLSettingsSky::SETTING_GAMMA("gamma");
const std::string LLSettingsSky::SETTING_GLOW("glow");

const std::string LLSettingsSky::SETTING_LIGHT_NORMAL("lightnorm");
const std::string LLSettingsSky::SETTING_MAX_Y("max_y");
const std::string LLSettingsSky::SETTING_MOON_ROTATION("moon_rotation");
const std::string LLSettingsSky::SETTING_MOON_TEXTUREID("moon_id");
const std::string LLSettingsSky::SETTING_STAR_BRIGHTNESS("star_brightness");
const std::string LLSettingsSky::SETTING_SUNLIGHT_COLOR("sunlight_color");
const std::string LLSettingsSky::SETTING_SUN_ROTATION("sun_rotation");
const std::string LLSettingsSky::SETTING_SUN_TEXTUREID("sun_id");

const std::string LLSettingsSky::SETTING_LEGACY_EAST_ANGLE("east_angle");
const std::string LLSettingsSky::SETTING_LEGACY_ENABLE_CLOUD_SCROLL("enable_cloud_scroll");
const std::string LLSettingsSky::SETTING_LEGACY_SUN_ANGLE("sun_angle");

// these are new settings for the advanced atmospherics model
const std::string LLSettingsSky::SETTING_PLANET_RADIUS("planet_radius");
const std::string LLSettingsSky::SETTING_SKY_BOTTOM_RADIUS("sky_bottom_radius");
const std::string LLSettingsSky::SETTING_SKY_TOP_RADIUS("sky_top_radius");
const std::string LLSettingsSky::SETTING_SUN_ARC_RADIANS("sun_arc_radians");

const std::string LLSettingsSky::SETTING_RAYLEIGH_CONFIG("rayleigh_config");
const std::string LLSettingsSky::SETTING_MIE_CONFIG("mie_config");
const std::string LLSettingsSky::SETTING_MIE_ANISOTROPY_FACTOR("anisotropy");
const std::string LLSettingsSky::SETTING_ABSORPTION_CONFIG("absorption_config");

const std::string LLSettingsSky::KEY_DENSITY_PROFILE("density");
const std::string LLSettingsSky::SETTING_DENSITY_PROFILE_WIDTH("width");
const std::string LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_TERM("exp_term");
const std::string LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR("exp_scale");
const std::string LLSettingsSky::SETTING_DENSITY_PROFILE_LINEAR_TERM("linear_term");
const std::string LLSettingsSky::SETTING_DENSITY_PROFILE_CONSTANT_TERM("constant_term");

// *LAPRAS* Change when Agni!
static const LLUUID DEFAULT_SUN_ID("cce0f112-878f-4586-a2e2-a8f104bba271"); // dataserver
static const LLUUID DEFAULT_MOON_ID("d07f6eed-b96a-47cd-b51d-400ad4a1c428"); // dataserver
static const LLUUID DEFAULT_CLOUD_ID("1dc1368f-e8fe-f02d-a08d-9d9f11c1af6b");
static const LLUUID DEFAULT_ASSET_ID("cec9af47-90d4-9093-5245-397e5c9e7749");

const std::string LLSettingsSky::SETTING_LEGACY_HAZE("legacy_haze");

namespace
{

LLSettingsSky::validation_list_t legacyHazeValidationList()
{
    static LLSettingsBase::validation_list_t legacyHazeValidation;
    if (legacyHazeValidation.empty())
    {
        legacyHazeValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_BLUE_DENSITY,        true,  LLSD::TypeArray, 
            boost::bind(&LLSettingsBase::Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(2.0f)(2.0f)(2.0f)("*")))));
        legacyHazeValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_BLUE_HORIZON,        true,  LLSD::TypeArray, 
            boost::bind(&LLSettingsBase::Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(2.0f)(2.0f)(2.0f)("*")))));
        legacyHazeValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_HAZE_DENSITY,        true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(4.0f)))));
        legacyHazeValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_HAZE_HORIZON,        true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
        legacyHazeValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_MULTIPLIER,  true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(0.0009f)))));
        legacyHazeValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DISTANCE_MULTIPLIER, true,  LLSD::TypeReal,
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(100.0f)))));
    }
    return legacyHazeValidation;
}

LLSettingsSky::validation_list_t rayleighValidationList()
{
    static LLSettingsBase::validation_list_t rayleighValidation;
    if (rayleighValidation.empty())
    {
        rayleighValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_WIDTH,      true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(32768.0f)))));

        rayleighValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_TERM,   true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));
        
        rayleighValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(-1.0f)(1.0f)))));

        rayleighValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_LINEAR_TERM, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));

        rayleighValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_CONSTANT_TERM, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
    }
    return rayleighValidation;
}

LLSettingsSky::validation_list_t absorptionValidationList()
{
    static LLSettingsBase::validation_list_t absorptionValidation;
    if (absorptionValidation.empty())
    {
        absorptionValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_WIDTH,      true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(32768.0f)))));

        absorptionValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_TERM,   true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));
        
        absorptionValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(-1.0f)(1.0f)))));

        absorptionValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_LINEAR_TERM, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));

        absorptionValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_CONSTANT_TERM, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
    }
    return absorptionValidation;
}

LLSettingsSky::validation_list_t mieValidationList()
{
    static LLSettingsBase::validation_list_t mieValidation;
    if (mieValidation.empty())
    {
        mieValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_WIDTH,      true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(32768.0f)))));

        mieValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_TERM,   true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));
        
        mieValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(-1.0f)(1.0f)))));

        mieValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_LINEAR_TERM, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));

        mieValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_DENSITY_PROFILE_CONSTANT_TERM, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));

        mieValidation.push_back(LLSettingsBase::Validator(LLSettingsSky::SETTING_MIE_ANISOTROPY_FACTOR, true,  LLSD::TypeReal,  
            boost::bind(&LLSettingsBase::Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
    }
    return mieValidation;
}

bool validateLegacyHaze(LLSD &value)
{
    LLSettingsSky::validation_list_t legacyHazeValidations = legacyHazeValidationList();
    llassert(value.type() == LLSD::TypeMap);
    LLSD result = LLSettingsBase::settingValidation(value, legacyHazeValidations);
    if (result["errors"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Legacy Haze Config Validation errors: " << result["errors"] << LL_ENDL;
        return false;
    }
    if (result["warnings"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Legacy Haze Config Validation warnings: " << result["warnings"] << LL_ENDL;
        return false;
    }
    return true;
}

bool validateRayleighLayers(LLSD &value)
{
    LLSettingsSky::validation_list_t rayleighValidations = rayleighValidationList();
    if (value.isArray())
    {
        bool allGood = true;
        for (LLSD::array_iterator itf = value.beginArray(); itf != value.endArray(); ++itf)
        {
            LLSD& layerConfig = (*itf);
            if (layerConfig.type() == LLSD::TypeMap)
            {
                if (!validateRayleighLayers(layerConfig))
                {
                    allGood = false;
                }
            }
            else if (layerConfig.type() == LLSD::TypeArray)
            {
                return validateRayleighLayers(layerConfig);
            }
            else
            {
                return LLSettingsBase::settingValidation(value, rayleighValidations);
            }
        }
        return allGood;
    }    
    llassert(value.type() == LLSD::TypeMap);
    LLSD result = LLSettingsBase::settingValidation(value, rayleighValidations);
    if (result["errors"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Rayleigh Config Validation errors: " << result["errors"] << LL_ENDL;
        return false;
    }
    if (result["warnings"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Rayleigh Config Validation warnings: " << result["errors"] << LL_ENDL;
        return false;
    }
    return true;
}

bool validateAbsorptionLayers(LLSD &value)
{
    LLSettingsBase::validation_list_t absorptionValidations = absorptionValidationList();
    if (value.isArray())
    {
        bool allGood = true;   
        for (LLSD::array_iterator itf = value.beginArray(); itf != value.endArray(); ++itf)
        {
            LLSD& layerConfig = (*itf);
            if (layerConfig.type() == LLSD::TypeMap)
            {
                if (!validateAbsorptionLayers(layerConfig))
                {
                    allGood = false;
                }
            }
            else if (layerConfig.type() == LLSD::TypeArray)
            {
                return validateAbsorptionLayers(layerConfig);
            }
            else
            {
                return LLSettingsBase::settingValidation(value, absorptionValidations);
            }
        }
        return allGood;
    }
    llassert(value.type() == LLSD::TypeMap);
    LLSD result = LLSettingsBase::settingValidation(value, absorptionValidations);
    if (result["errors"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Absorption Config Validation errors: " << result["errors"] << LL_ENDL;
        return false;
    }
    if (result["warnings"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Absorption Config Validation warnings: " << result["errors"] << LL_ENDL;
        return false;
    }
    return true;
}

bool validateMieLayers(LLSD &value)
{
    LLSettingsBase::validation_list_t mieValidations = mieValidationList();
    if (value.isArray())
    {
        bool allGood = true;
        for (LLSD::array_iterator itf = value.beginArray(); itf != value.endArray(); ++itf)
        {
            LLSD& layerConfig = (*itf);
            if (layerConfig.type() == LLSD::TypeMap)
            {
                if (!validateMieLayers(layerConfig))
                {
                    allGood = false;
                }
            }
            else if (layerConfig.type() == LLSD::TypeArray)
            {
                return validateMieLayers(layerConfig);
            }
            else
            {
                return LLSettingsBase::settingValidation(value, mieValidations);
            }
        }
        return allGood;
    }
    LLSD result = LLSettingsBase::settingValidation(value, mieValidations);
    if (result["errors"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Mie Config Validation errors: " << result["errors"] << LL_ENDL;
        return false;
    }
    if (result["warnings"].size() > 0)
    {
        LL_WARNS("SETTINGS") << "Mie Config Validation warnings: " << result["warnings"] << LL_ENDL;
        return false;
    }
    return true;
}

}

//=========================================================================
LLSettingsSky::LLSettingsSky(const LLSD &data) :
    LLSettingsBase(data),
    mNextSunTextureId(),
    mNextMoonTextureId(),
    mNextCloudTextureId(),
    mPositionsDirty(true),
    mLightingDirty(true)
{
}

LLSettingsSky::LLSettingsSky():
    LLSettingsBase(),
    mNextSunTextureId(),
    mNextMoonTextureId(),
    mNextCloudTextureId(),
    mPositionsDirty(true),
    mLightingDirty(true)
{
}

void LLSettingsSky::blend(const LLSettingsBase::ptr_t &end, F64 blendf) 
{
    LLSettingsSky::ptr_t other = PTR_NAMESPACE::dynamic_pointer_cast<LLSettingsSky>(end);
    LLSD blenddata = interpolateSDMap(mSettings, other->mSettings, blendf);

    replaceSettings(blenddata);
    setBlendFactor(blendf);
    mNextSunTextureId = other->getSunTextureId();
    mNextMoonTextureId = other->getMoonTextureId();
    mNextCloudTextureId = other->getCloudNoiseTextureId();
}

LLSettingsSky::stringset_t LLSettingsSky::getSkipInterpolateKeys() const
{
    static stringset_t skipSet;

    if (skipSet.empty())
    {
        skipSet.insert(SETTING_RAYLEIGH_CONFIG);
        skipSet.insert(SETTING_MIE_CONFIG);
        skipSet.insert(SETTING_ABSORPTION_CONFIG);
    }

    return skipSet;
}

LLSettingsSky::stringset_t LLSettingsSky::getSlerpKeys() const 
{ 
    static stringset_t slepSet;

    if (slepSet.empty())
    {
        slepSet.insert(SETTING_SUN_ROTATION);
        slepSet.insert(SETTING_MOON_ROTATION);
    }

    return slepSet;
}

LLSettingsSky::validation_list_t LLSettingsSky::getValidationList() const
{
    return LLSettingsSky::validationList();
}

LLSettingsSky::validation_list_t LLSettingsSky::validationList()
{
    static validation_list_t validation;

    if (validation.empty())
    {   // Note the use of LLSD(LLSDArray()()()...) This is due to an issue with the 
        // copy constructor for LLSDArray.  Directly binding the LLSDArray as 
        // a parameter without first wrapping it in a pure LLSD object will result 
        // in deeply nested arrays like this [[[[[[[[[[v1,v2,v3]]]]]]]]]]
        validation.push_back(Validator(SETTING_BLUE_DENSITY,        false,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(2.0f)(2.0f)(2.0f)("*")))));
        validation.push_back(Validator(SETTING_BLUE_HORIZON,        false,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(2.0f)(2.0f)(2.0f)("*")))));
        validation.push_back(Validator(SETTING_HAZE_DENSITY,        false,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(4.0f)))));
        validation.push_back(Validator(SETTING_HAZE_HORIZON,        false,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
        validation.push_back(Validator(SETTING_AMBIENT, false, LLSD::TypeArray,
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(3.0f)(3.0f)(3.0f)("*")))));
        validation.push_back(Validator(SETTING_DENSITY_MULTIPLIER,  false,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(0.0009f)))));
        validation.push_back(Validator(SETTING_DISTANCE_MULTIPLIER, false,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(100.0f)))));


        validation.push_back(Validator(SETTING_BLOOM_TEXTUREID,     true,  LLSD::TypeUUID));
        validation.push_back(Validator(SETTING_CLOUD_COLOR,         true,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(1.0f)(1.0f)(1.0f)("*")))));
        validation.push_back(Validator(SETTING_CLOUD_POS_DENSITY1,  true,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(1.68841f)(1.0f)(1.0f)("*")))));
        validation.push_back(Validator(SETTING_CLOUD_POS_DENSITY2,  true,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(1.68841f)(1.0f)(1.0f)("*")))));
        validation.push_back(Validator(SETTING_CLOUD_SCALE,         true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.001f)(0.999f)))));
        validation.push_back(Validator(SETTING_CLOUD_SCROLL_RATE,   true,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)),
                LLSD(LLSDArray(20.0f)(20.0f)))));
        validation.push_back(Validator(SETTING_CLOUD_SHADOW,        true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
        validation.push_back(Validator(SETTING_CLOUD_TEXTUREID,     false, LLSD::TypeUUID));

        validation.push_back(Validator(SETTING_DOME_OFFSET,         false, LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(1.0f)))));
        validation.push_back(Validator(SETTING_DOME_RADIUS,         false, LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(1000.0f)(2000.0f)))));
        validation.push_back(Validator(SETTING_GAMMA,               true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(10.0f)))));
        validation.push_back(Validator(SETTING_GLOW,                true,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.2f)("*")(-2.5f)("*")),
                LLSD(LLSDArray(20.0f)("*")(0.0f)("*")))));
        
        validation.push_back(Validator(SETTING_MAX_Y,               true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(4000.0f)))));
        validation.push_back(Validator(SETTING_MOON_ROTATION,       true,  LLSD::TypeArray, &Validator::verifyQuaternionNormal));
        validation.push_back(Validator(SETTING_MOON_TEXTUREID,      false, LLSD::TypeUUID));
        validation.push_back(Validator(SETTING_STAR_BRIGHTNESS,     true,  LLSD::TypeReal, 
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(2.0f)))));
        validation.push_back(Validator(SETTING_SUNLIGHT_COLOR,      true,  LLSD::TypeArray, 
            boost::bind(&Validator::verifyVectorMinMax, _1,
                LLSD(LLSDArray(0.0f)(0.0f)(0.0f)("*")),
                LLSD(LLSDArray(3.0f)(3.0f)(3.0f)("*")))));
        validation.push_back(Validator(SETTING_SUN_ROTATION,        true,  LLSD::TypeArray, &Validator::verifyQuaternionNormal));
        validation.push_back(Validator(SETTING_SUN_TEXTUREID,      false, LLSD::TypeUUID));

        validation.push_back(Validator(SETTING_PLANET_RADIUS,       true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(1000.0f)(32768.0f)))));

        validation.push_back(Validator(SETTING_SKY_BOTTOM_RADIUS,   true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(1000.0f)(32768.0f)))));

        validation.push_back(Validator(SETTING_SKY_TOP_RADIUS,       true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(1000.0f)(32768.0f)))));

        validation.push_back(Validator(SETTING_SUN_ARC_RADIANS,      true,  LLSD::TypeReal,  
            boost::bind(&Validator::verifyFloatRange, _1, LLSD(LLSDArray(0.0f)(0.1f)))));

        validation.push_back(Validator(SETTING_RAYLEIGH_CONFIG, true, LLSD::TypeArray, &validateRayleighLayers));
        validation.push_back(Validator(SETTING_ABSORPTION_CONFIG, true, LLSD::TypeArray, &validateAbsorptionLayers));
        validation.push_back(Validator(SETTING_MIE_CONFIG, true, LLSD::TypeArray, &validateMieLayers));
        validation.push_back(Validator(SETTING_LEGACY_HAZE, false, LLSD::TypeMap, &validateLegacyHaze));
    }
    return validation;
}

LLSD LLSettingsSky::rayleighConfigDefault()
{
    LLSD dflt_rayleigh;
    LLSD dflt_rayleigh_layer;
    dflt_rayleigh_layer[SETTING_DENSITY_PROFILE_WIDTH]            = 0.0f; // 0 -> the entire atmosphere
    dflt_rayleigh_layer[SETTING_DENSITY_PROFILE_EXP_TERM]         = 1.0f;
    dflt_rayleigh_layer[SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR] = -1.0f / 8000.0f;
    dflt_rayleigh_layer[SETTING_DENSITY_PROFILE_LINEAR_TERM]      = 0.0f;
    dflt_rayleigh_layer[SETTING_DENSITY_PROFILE_CONSTANT_TERM]    = 0.0f;
    dflt_rayleigh.append(dflt_rayleigh_layer);
    return dflt_rayleigh;
}

LLSD LLSettingsSky::absorptionConfigDefault()
{
// absorption (ozone) has two linear ramping zones
    LLSD dflt_absorption_layer_a;
    dflt_absorption_layer_a[SETTING_DENSITY_PROFILE_WIDTH]            = 25000.0f; // 0 -> the entire atmosphere
    dflt_absorption_layer_a[SETTING_DENSITY_PROFILE_EXP_TERM]         = 0.0f;
    dflt_absorption_layer_a[SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR] = 0.0f;
    dflt_absorption_layer_a[SETTING_DENSITY_PROFILE_LINEAR_TERM]      = -1.0f / 25000.0f;
    dflt_absorption_layer_a[SETTING_DENSITY_PROFILE_CONSTANT_TERM]    = -2.0f / 3.0f;

    LLSD dflt_absorption_layer_b;
    dflt_absorption_layer_b[SETTING_DENSITY_PROFILE_WIDTH]            = 0.0f; // 0 -> remainder of the atmosphere
    dflt_absorption_layer_b[SETTING_DENSITY_PROFILE_EXP_TERM]         = 0.0f;
    dflt_absorption_layer_b[SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR] = 0.0f;
    dflt_absorption_layer_b[SETTING_DENSITY_PROFILE_LINEAR_TERM]      = -1.0f / 15000.0f;
    dflt_absorption_layer_b[SETTING_DENSITY_PROFILE_CONSTANT_TERM]    = 8.0f  / 3.0f;

    LLSD dflt_absorption;
    dflt_absorption.append(dflt_absorption_layer_a);
    dflt_absorption.append(dflt_absorption_layer_b);
    return dflt_absorption;
}

LLSD LLSettingsSky::mieConfigDefault()
{
    LLSD dflt_mie;
    LLSD dflt_mie_layer;
    dflt_mie_layer[SETTING_DENSITY_PROFILE_WIDTH]            = 0.0f; // 0 -> the entire atmosphere
    dflt_mie_layer[SETTING_DENSITY_PROFILE_EXP_TERM]         = 1.0f;
    dflt_mie_layer[SETTING_DENSITY_PROFILE_EXP_SCALE_FACTOR] = -1.0f / 1200.0f;
    dflt_mie_layer[SETTING_DENSITY_PROFILE_LINEAR_TERM]      = 0.0f;
    dflt_mie_layer[SETTING_DENSITY_PROFILE_CONSTANT_TERM]    = 0.0f;
    dflt_mie_layer[SETTING_MIE_ANISOTROPY_FACTOR]            = 0.8f;
    dflt_mie.append(dflt_mie_layer);
    return dflt_mie;
}

LLSD LLSettingsSky::defaults()
{
    LLSD dfltsetting;
    LLQuaternion sunquat;
    LLQuaternion moonquat;

    sunquat  = convert_azimuth_and_altitude_to_quat(0.0f, 80.0f * DEG_TO_RAD);
    moonquat = convert_azimuth_and_altitude_to_quat(F_PI, 80.0f * DEG_TO_RAD);

    // Magic constants copied form dfltsetting.xml 
    dfltsetting[SETTING_CLOUD_COLOR]        = LLColor4(0.4099, 0.4099, 0.4099, 0.0).getValue();
    dfltsetting[SETTING_CLOUD_POS_DENSITY1] = LLColor4(1.0000, 0.5260, 1.0000, 0.0).getValue();
    dfltsetting[SETTING_CLOUD_POS_DENSITY2] = LLColor4(1.0000, 0.5260, 1.0000, 0.0).getValue();
    dfltsetting[SETTING_CLOUD_SCALE]        = LLSD::Real(0.4199);
    dfltsetting[SETTING_CLOUD_SCROLL_RATE]  = LLSDArray(10.1999)(10.0109);
    dfltsetting[SETTING_CLOUD_SHADOW]       = LLSD::Real(0.2699);
    
    dfltsetting[SETTING_DOME_OFFSET]        = LLSD::Real(0.96f);
    dfltsetting[SETTING_DOME_RADIUS]        = LLSD::Real(15000.f);
    dfltsetting[SETTING_GAMMA]              = LLSD::Real(1.0);
    dfltsetting[SETTING_GLOW]               = LLColor4(5.000, 0.0010, -0.4799, 1.0).getValue();
    
    dfltsetting[SETTING_MAX_Y]              = LLSD::Real(1605);
    dfltsetting[SETTING_MOON_ROTATION]      = moonquat.getValue();
    dfltsetting[SETTING_STAR_BRIGHTNESS]    = LLSD::Real(0.0000);
    dfltsetting[SETTING_SUNLIGHT_COLOR]     = LLColor4(0.7342, 0.7815, 0.8999, 0.0).getValue();
    dfltsetting[SETTING_SUN_ROTATION]       = sunquat.getValue();

    dfltsetting[SETTING_BLOOM_TEXTUREID]    = IMG_BLOOM1;
    dfltsetting[SETTING_CLOUD_TEXTUREID]    = GetDefaultCloudNoiseTextureId();
    dfltsetting[SETTING_MOON_TEXTUREID]     = GetDefaultMoonTextureId();
    dfltsetting[SETTING_SUN_TEXTUREID]      = GetDefaultSunTextureId();

    dfltsetting[SETTING_TYPE] = "sky";

    // defaults are for earth...
    dfltsetting[SETTING_PLANET_RADIUS]      = 6360.0f;
    dfltsetting[SETTING_SKY_BOTTOM_RADIUS]  = 6360.0f;
    dfltsetting[SETTING_SKY_TOP_RADIUS]     = 6420.0f;
    dfltsetting[SETTING_SUN_ARC_RADIANS]    = 0.00935f / 2.0f;    

    dfltsetting[SETTING_RAYLEIGH_CONFIG]    = rayleighConfigDefault();
    dfltsetting[SETTING_MIE_CONFIG]         = mieConfigDefault();
    dfltsetting[SETTING_ABSORPTION_CONFIG]  = absorptionConfigDefault();

    return dfltsetting;
}

LLSD LLSettingsSky::translateLegacyHazeSettings(const LLSD& legacy)
{
    LLSD legacyhazesettings;

// AdvancedAtmospherics TODO
// These need to be translated into density profile info in the new settings format...
// LEGACY_ATMOSPHERICS    
    if (legacy.has(SETTING_BLUE_DENSITY))
    {
        legacyhazesettings[SETTING_BLUE_DENSITY] = LLColor3(legacy[SETTING_BLUE_DENSITY]).getValue();
    }
    if (legacy.has(SETTING_BLUE_HORIZON))
    {
        legacyhazesettings[SETTING_BLUE_HORIZON] = LLColor3(legacy[SETTING_BLUE_HORIZON]).getValue();
    }
    if (legacy.has(SETTING_DENSITY_MULTIPLIER))
    {
        legacyhazesettings[SETTING_DENSITY_MULTIPLIER] = LLSD::Real(legacy[SETTING_DENSITY_MULTIPLIER][0].asReal());
    }
    if (legacy.has(SETTING_DISTANCE_MULTIPLIER))
    {
        legacyhazesettings[SETTING_DISTANCE_MULTIPLIER] = LLSD::Real(legacy[SETTING_DISTANCE_MULTIPLIER][0].asReal());
    }
    if (legacy.has(SETTING_HAZE_DENSITY))
    {
        legacyhazesettings[SETTING_HAZE_DENSITY] = LLSD::Real(legacy[SETTING_HAZE_DENSITY][0].asReal());
    }
    if (legacy.has(SETTING_HAZE_HORIZON))
    {
        legacyhazesettings[SETTING_HAZE_HORIZON] = LLSD::Real(legacy[SETTING_HAZE_HORIZON][0].asReal());
    }

    return legacyhazesettings;
}

LLSD LLSettingsSky::translateLegacySettings(const LLSD& legacy)
{
    LLSD newsettings(defaults());

    // Move legacy haze parameters to an inner map
    // allowing backward compat and simple conversion to legacy format
    LLSD legacyhazesettings;
    legacyhazesettings = translateLegacyHazeSettings(legacy);
    if (legacyhazesettings.size() > 0)
    {
        newsettings[SETTING_LEGACY_HAZE] = legacyhazesettings;
    }

    if (legacy.has(SETTING_AMBIENT))
    {
        newsettings[SETTING_AMBIENT] = LLColor3(legacy[SETTING_AMBIENT]).getValue();
    }
    if (legacy.has(SETTING_CLOUD_COLOR))
    {
        newsettings[SETTING_CLOUD_COLOR] = LLColor3(legacy[SETTING_CLOUD_COLOR]).getValue();
    }
    if (legacy.has(SETTING_CLOUD_POS_DENSITY1))
    {
        newsettings[SETTING_CLOUD_POS_DENSITY1] = LLColor3(legacy[SETTING_CLOUD_POS_DENSITY1]).getValue();
    }
    if (legacy.has(SETTING_CLOUD_POS_DENSITY2))
    {
        newsettings[SETTING_CLOUD_POS_DENSITY2] = LLColor3(legacy[SETTING_CLOUD_POS_DENSITY2]).getValue();
    }
    if (legacy.has(SETTING_CLOUD_SCALE))
    {
        newsettings[SETTING_CLOUD_SCALE] = LLSD::Real(legacy[SETTING_CLOUD_SCALE][0].asReal());
    }
    if (legacy.has(SETTING_CLOUD_SCROLL_RATE))
    {
        LLVector2 cloud_scroll(legacy[SETTING_CLOUD_SCROLL_RATE]);

        if (legacy.has(SETTING_LEGACY_ENABLE_CLOUD_SCROLL))
        {
            LLSD enabled = legacy[SETTING_LEGACY_ENABLE_CLOUD_SCROLL];
            if (!enabled[0].asBoolean())
                cloud_scroll.mV[0] = 0.0f;
            if (!enabled[1].asBoolean())
                cloud_scroll.mV[1] = 0.0f;
        }

        newsettings[SETTING_CLOUD_SCROLL_RATE] = cloud_scroll.getValue();
    }
    if (legacy.has(SETTING_CLOUD_SHADOW))
    {
        newsettings[SETTING_CLOUD_SHADOW] = LLSD::Real(legacy[SETTING_CLOUD_SHADOW][0].asReal());
    }
    

    if (legacy.has(SETTING_GAMMA))
    {
        newsettings[SETTING_GAMMA] = legacy[SETTING_GAMMA][0].asReal();
    }
    if (legacy.has(SETTING_GLOW))
    {
        newsettings[SETTING_GLOW] = LLColor3(legacy[SETTING_GLOW]).getValue();
    }

    if (legacy.has(SETTING_MAX_Y))
    {
        newsettings[SETTING_MAX_Y] = LLSD::Real(legacy[SETTING_MAX_Y][0].asReal());
    }
    if (legacy.has(SETTING_STAR_BRIGHTNESS))
    {
        newsettings[SETTING_STAR_BRIGHTNESS] = LLSD::Real(legacy[SETTING_STAR_BRIGHTNESS].asReal());
    }
    if (legacy.has(SETTING_SUNLIGHT_COLOR))
    {
        newsettings[SETTING_SUNLIGHT_COLOR] = LLColor4(legacy[SETTING_SUNLIGHT_COLOR]).getValue();
    }

    if (legacy.has(SETTING_PLANET_RADIUS))
    {
        newsettings[SETTING_PLANET_RADIUS] = LLSD::Real(legacy[SETTING_PLANET_RADIUS].asReal());
    }

    if (legacy.has(SETTING_SKY_BOTTOM_RADIUS))
    {
        newsettings[SETTING_SKY_BOTTOM_RADIUS] = LLSD::Real(legacy[SETTING_SKY_BOTTOM_RADIUS].asReal());
    }

    if (legacy.has(SETTING_SKY_TOP_RADIUS))
    {
        newsettings[SETTING_SKY_TOP_RADIUS] = LLSD::Real(legacy[SETTING_SKY_TOP_RADIUS].asReal());
    }

    if (legacy.has(SETTING_SUN_ARC_RADIANS))
    {
        newsettings[SETTING_SUN_ARC_RADIANS] = LLSD::Real(legacy[SETTING_SUN_ARC_RADIANS].asReal());
    }

    if (legacy.has(SETTING_LEGACY_EAST_ANGLE) && legacy.has(SETTING_LEGACY_SUN_ANGLE))
    {   // convert the east and sun angles into a quaternion.
        F32 azimuth  = legacy[SETTING_LEGACY_EAST_ANGLE].asReal();
        F32 altitude = legacy[SETTING_LEGACY_SUN_ANGLE].asReal();

        LLQuaternion sunquat  = convert_azimuth_and_altitude_to_quat(azimuth, altitude);
        LLQuaternion moonquat = convert_azimuth_and_altitude_to_quat(azimuth + F_PI, altitude);

        //LLVector3 sundir  = DUE_EAST * sunquat;
        //LLVector3 moondir = DUE_EAST * moonquat;

        newsettings[SETTING_SUN_ROTATION]  = sunquat.getValue();
        newsettings[SETTING_MOON_ROTATION] = moonquat.getValue();
    }

    return newsettings;
}

void LLSettingsSky::updateSettings()
{
    mPositionsDirty = isDirty();
    mLightingDirty  = isDirty();

    // base class clears dirty flag so as to not trigger recursive update
    LLSettingsBase::updateSettings();
}

bool LLSettingsSky::getIsSunUp() const
{
    LLVector3 sunDir = getSunDirection();
    return sunDir.mV[2] > NIGHTTIME_ELEVATION_SIN;
}

bool LLSettingsSky::getIsMoonUp() const
{
    LLVector3 moonDir = getMoonDirection();
    return moonDir.mV[2] > NIGHTTIME_ELEVATION_SIN;
}

void LLSettingsSky::calculateHeavenlyBodyPositions()  const
{
    if (!mPositionsDirty)
    {
        return;
    }

    mPositionsDirty = false;

    LLQuaternion sunq  = getSunRotation();
    LLQuaternion moonq = getMoonRotation();

    mSunDirection  = DUE_EAST * sunq;
    mMoonDirection = DUE_EAST * moonq;

    mSunDirection.normalize();
    mMoonDirection.normalize();
}

LLVector3 LLSettingsSky::getLightDirection() const
{
    calculateHeavenlyBodyPositions();

    // is the normal from the sun or the moon
    if (getIsSunUp())
    {
        llassert(mSunDirection.length() > 0.01f);
        return mSunDirection;
    }
    else if (getIsMoonUp())
    {
        llassert(mMoonDirection.length() > 0.01f);
        return mMoonDirection;
    }

    return LLVector3::z_axis;
}

LLColor3 LLSettingsSky::getBlueDensity() const
{
    if (mSettings.has(SETTING_LEGACY_HAZE) && mSettings[SETTING_LEGACY_HAZE].has(SETTING_BLUE_DENSITY))
    {
        return LLColor3(mSettings[SETTING_LEGACY_HAZE][SETTING_BLUE_DENSITY]);
    }
    return LLColor3(0.2447f, 0.4487f, 0.7599f);
}

LLColor3 LLSettingsSky::getBlueHorizon() const
{
    if (mSettings.has(SETTING_LEGACY_HAZE) && mSettings[SETTING_LEGACY_HAZE].has(SETTING_BLUE_DENSITY))
    {
        return LLColor3(mSettings[SETTING_LEGACY_HAZE][SETTING_BLUE_HORIZON]);
    }
    return LLColor3(0.4954f, 0.4954f, 0.6399f);
}

F32 LLSettingsSky::getHazeDensity() const
{
    if (mSettings.has(SETTING_LEGACY_HAZE) && mSettings[SETTING_LEGACY_HAZE].has(SETTING_HAZE_DENSITY))
    {
        return mSettings[SETTING_LEGACY_HAZE][SETTING_HAZE_DENSITY].asReal();
    }
    return 0.7f;
}

F32 LLSettingsSky::getHazeHorizon() const
{
    if (mSettings.has(SETTING_LEGACY_HAZE) && mSettings[SETTING_LEGACY_HAZE].has(SETTING_HAZE_HORIZON))
    {
        return mSettings[SETTING_LEGACY_HAZE][SETTING_HAZE_HORIZON].asReal();
    }
    return 0.19f;
}

F32 LLSettingsSky::getDensityMultiplier() const
{
    if (mSettings.has(SETTING_LEGACY_HAZE) && mSettings[SETTING_LEGACY_HAZE].has(SETTING_DENSITY_MULTIPLIER))
    {
        return mSettings[SETTING_LEGACY_HAZE][SETTING_DENSITY_MULTIPLIER].asReal();
    }
    return 0.0001f;
}

F32 LLSettingsSky::getDistanceMultiplier() const
{
    if (mSettings.has(SETTING_LEGACY_HAZE) && mSettings[SETTING_LEGACY_HAZE].has(SETTING_DISTANCE_MULTIPLIER))
    {
        return mSettings[SETTING_LEGACY_HAZE][SETTING_DISTANCE_MULTIPLIER].asReal();
    }
    return 0.8f;
}

void LLSettingsSky::setBlueDensity(const LLColor3 &val)
{
    mSettings[SETTING_LEGACY_HAZE][SETTING_BLUE_DENSITY] = val.getValue();
    markDirty();
}

void LLSettingsSky::setBlueHorizon(const LLColor3 &val)
{
    mSettings[SETTING_LEGACY_HAZE][SETTING_BLUE_HORIZON] = val.getValue();
    markDirty();
}

void LLSettingsSky::setDensityMultiplier(F32 val)
{
    mSettings[SETTING_LEGACY_HAZE][SETTING_DENSITY_MULTIPLIER] = val;
    markDirty();
}

void LLSettingsSky::setDistanceMultiplier(F32 val)
{
    mSettings[SETTING_LEGACY_HAZE][SETTING_DISTANCE_MULTIPLIER] = val;
    markDirty();
}

void LLSettingsSky::setHazeDensity(F32 val)
{
    mSettings[SETTING_LEGACY_HAZE][SETTING_HAZE_DENSITY] = val;
    markDirty();
}
void LLSettingsSky::setHazeHorizon(F32 val)
{
    mSettings[SETTING_LEGACY_HAZE][SETTING_HAZE_HORIZON] = val;
    markDirty();
}

// Sunlight attenuation effect (hue and brightness) due to atmosphere
// this is used later for sunlight modulation at various altitudes
LLColor3 LLSettingsSky::getLightAttenuation(F32 distance) const
{
// LEGACY_ATMOSPHERICS
    LLColor3    blue_density = getBlueDensity();
    F32         haze_density = getHazeDensity();
    F32         density_multiplier = getDensityMultiplier();
    LLColor3    density = (blue_density * 1.0 + smear(haze_density * 0.25f));
    LLColor3    light_atten = density * density_multiplier * distance;
    return light_atten;
}

LLColor3 LLSettingsSky::getLightTransmittance() const
{
// LEGACY_ATMOSPHERICS
    LLColor3    blue_density = getBlueDensity();
    F32         haze_density = getHazeDensity();
    F32         density_multiplier = getDensityMultiplier();
    LLColor3 temp1 = blue_density + smear(haze_density);
    // Transparency (-> temp1)
    temp1 = componentExp((temp1 * -1.f) * density_multiplier);
    return temp1;
}

LLColor3 LLSettingsSky::gammaCorrect(const LLColor3& in) const
{
    F32 gamma = getGamma();
    LLColor3 v(in);
    v.clamp();
    v= smear(1.0f) - v;
    v = componentPow(v, gamma);
    v = smear(1.0f) - v;
    return v;
}

LLVector3 LLSettingsSky::getSunDirection() const
{
    calculateHeavenlyBodyPositions();
    return mSunDirection;
}

LLVector3 LLSettingsSky::getMoonDirection() const
{
    calculateHeavenlyBodyPositions();
    return mMoonDirection;
}

LLColor4U LLSettingsSky::getFadeColor() const
{
    calculateLightSettings();
    return mFadeColor;
}

LLColor4 LLSettingsSky::getMoonAmbient() const
{
    calculateLightSettings();
    return mMoonAmbient;
}

LLColor3 LLSettingsSky::getMoonDiffuse() const
{
    calculateLightSettings();
    return mMoonDiffuse;
}

LLColor4 LLSettingsSky::getSunAmbient() const
{
    calculateLightSettings();
    return mSunAmbient;
}

LLColor3 LLSettingsSky::getSunDiffuse() const
{
    calculateLightSettings();
    return mSunDiffuse;
}

LLColor4 LLSettingsSky::getTotalAmbient() const
{
    calculateLightSettings();
    return mTotalAmbient;
}

void LLSettingsSky::calculateLightSettings() const
{
    if (!mLightingDirty)
    {
        return;
    }

    calculateHeavenlyBodyPositions();

    mLightingDirty = false;

    // Initialize temp variables
    LLColor3    sunlight = getSunlightColor();
    LLColor3    ambient = getAmbientColor();
    F32         cloud_shadow = getCloudShadow();
    LLVector3   lightnorm = getLightDirection();

    // Sunlight attenuation effect (hue and brightness) due to atmosphere
    // this is used later for sunlight modulation at various altitudes
    F32      max_y = getMaxY();
    LLColor3 light_atten = getLightAttenuation(max_y);
    LLColor3 light_transmittance = getLightTransmittance();

    // and vary_sunlight will work properly with moon light
    F32 lighty = lightnorm[1];

    lighty = llmax(0.f, lighty);
    if(lighty > 0.f)
    {
        lighty = 1.f / lighty;
    }
    componentMultBy(sunlight, componentExp((light_atten * -1.f) * lighty));

    //increase ambient when there are more clouds
    LLColor3 tmpAmbient = ambient + (smear(1.f) - ambient) * cloud_shadow * 0.5f;

    //brightness of surface both sunlight and ambient
    mSunDiffuse = gammaCorrect(componentMult(sunlight, light_transmittance));       
    mSunAmbient = gammaCorrect(componentMult(tmpAmbient, light_transmittance) * 0.5);

    mMoonDiffuse  = gammaCorrect(componentMult(LLColor3::white, light_transmittance));
    mMoonAmbient  = gammaCorrect(componentMult(LLColor3::white, light_transmittance) * 0.5f);
    mTotalAmbient = mSunAmbient;

    mFadeColor = mTotalAmbient + (mSunDiffuse + mMoonDiffuse) * 0.5f;
    mFadeColor.setAlpha(0);
}

LLUUID LLSettingsSky::GetDefaultAssetId()
{
    return DEFAULT_ASSET_ID;
}

LLUUID LLSettingsSky::GetDefaultSunTextureId()
{
    return DEFAULT_SUN_ID;
}

LLUUID LLSettingsSky::GetDefaultMoonTextureId()
{
    return DEFAULT_MOON_ID;
}

LLUUID LLSettingsSky::GetDefaultCloudNoiseTextureId()
{
    return DEFAULT_CLOUD_ID;
}

void LLSettingsSky::setMoonRotation(const LLQuaternion &val)
{
    setValue(SETTING_MOON_ROTATION, val);
}