/** * @file llatmosphere.cpp * @brief LLAtmosphere integration impl * * $LicenseInfo:firstyear=2018&license=viewerlgpl$ * Second Life Viewer Source Code * Copyright (C) 2018, 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 "linden_common.h" #include "llatmosphere.h" #include "llfasttimer.h" #include "llsys.h" #include "llglheaders.h" #include "llrender.h" #include "llshadermgr.h" #include "llglslshader.h" LLAtmosphere* gAtmosphere = nullptr; void LLAtmosphere::initClass() { if (!gAtmosphere) { gAtmosphere = new LLAtmosphere; } } void LLAtmosphere::cleanupClass() { if(gAtmosphere) { delete gAtmosphere; } gAtmosphere = NULL; } LLAtmosphere::LLAtmosphere() { // Init libatmosphere model m_config.num_scattering_orders = 4; // Values from "Reference Solar Spectral Irradiance: ASTM G-173", ETR column // (see http://rredc.nrel.gov/solar/spectra/am1.5/ASTMG173/ASTMG173.html), // summed and averaged in each bin (e.g. the value for 360nm is the average // of the ASTM G-173 values for all wavelengths between 360 and 370nm). // Values in W.m^-2. const int kLambdaMin = 360; const int kLambdaMax = 830; const double kSolarIrradiance[48] = { 1.11776, 1.14259, 1.01249, 1.14716, 1.72765, 1.73054, 1.6887, 1.61253, 1.91198, 2.03474, 2.02042, 2.02212, 1.93377, 1.95809, 1.91686, 1.8298, 1.8685, 1.8931, 1.85149, 1.8504, 1.8341, 1.8345, 1.8147, 1.78158, 1.7533, 1.6965, 1.68194, 1.64654, 1.6048, 1.52143, 1.55622, 1.5113, 1.474, 1.4482, 1.41018, 1.36775, 1.34188, 1.31429, 1.28303, 1.26758, 1.2367, 1.2082, 1.18737, 1.14683, 1.12362, 1.1058, 1.07124, 1.04992 }; // Values from http://www.iup.uni-bremen.de/gruppen/molspec/databases/ // referencespectra/o3spectra2011/index.html for 233K, summed and averaged in // each bin (e.g. the value for 360nm is the average of the original values // for all wavelengths between 360 and 370nm). Values in m^2. const double kOzoneCrossSection[48] = { 1.18e-27, 2.182e-28, 2.818e-28, 6.636e-28, 1.527e-27, 2.763e-27, 5.52e-27, 8.451e-27, 1.582e-26, 2.316e-26, 3.669e-26, 4.924e-26, 7.752e-26, 9.016e-26, 1.48e-25, 1.602e-25, 2.139e-25, 2.755e-25, 3.091e-25, 3.5e-25, 4.266e-25, 4.672e-25, 4.398e-25, 4.701e-25, 5.019e-25, 4.305e-25, 3.74e-25, 3.215e-25, 2.662e-25, 2.238e-25, 1.852e-25, 1.473e-25, 1.209e-25, 9.423e-26, 7.455e-26, 6.566e-26, 5.105e-26, 4.15e-26, 4.228e-26, 3.237e-26, 2.451e-26, 2.801e-26, 2.534e-26, 1.624e-26, 1.465e-26, 2.078e-26, 1.383e-26, 7.105e-27 }; // From https://en.wikipedia.org/wiki/Dobson_unit, in molecules.m^-2. const double kDobsonUnit = 2.687e20; // Maximum number density of ozone molecules, in m^-3 (computed so at to get // 300 Dobson units of ozone - for this we divide 300 DU by the integral of // the ozone density profile defined below, which is equal to 15km). const double kMaxOzoneNumberDensity = 300.0 * kDobsonUnit / 15000.0; const double kSunAngularRadius = 0.00935 / 2.0; const double kBottomRadius = 6360000.0; const double kTopRadius = 6420000.0; const double kRayleigh = 1.24062e-6; const double kRayleighScaleHeight = 8000.0; const double kMieScaleHeight = 1200.0; const double kMieAngstromAlpha = 0.0; const double kMieAngstromBeta = 5.328e-3; const double kMieSingleScatteringAlbedo = 0.9; const double kMiePhaseFunctionG = 0.8; const double max_sun_zenith_angle = F_PI * 2.0 / 3.0; atmosphere::DensityProfileLayer rayleigh_density(0.0, 1.0, -1.0 / kRayleighScaleHeight, 0.0, 0.0); atmosphere::DensityProfileLayer mie_density(0.0, 1.0, -1.0 / kMieScaleHeight, 0.0, 0.0); // Density profile increasing linearly from 0 to 1 between 10 and 25km, and // decreasing linearly from 1 to 0 between 25 and 40km. This is an approximate // profile from http://www.kln.ac.lk/science/Chemistry/Teaching_Resources/ // Documents/Introduction%20to%20atmospheric%20chemistry.pdf (page 10). std::vector ozone_density; ozone_density.push_back(atmosphere::DensityProfileLayer(25000.0, 0.0, 0.0, 1.0 / 15000.0, -2.0 / 3.0)); ozone_density.push_back(atmosphere::DensityProfileLayer(0.0, 0.0, 0.0, -1.0 / 15000.0, 8.0 / 3.0)); std::vector wavelengths; std::vector solar_irradiance; std::vector rayleigh_scattering; std::vector mie_scattering; std::vector mie_extinction; std::vector absorption_extinction; std::vector ground_albedo; for (int l = kLambdaMin; l <= kLambdaMax; l += 10) { double lambda = static_cast(l) * 1e-3; // micro-meters double mie = kMieAngstromBeta / kMieScaleHeight * pow(lambda, -kMieAngstromAlpha); wavelengths.push_back(l); solar_irradiance.push_back(kSolarIrradiance[(l - kLambdaMin) / 10]); rayleigh_scattering.push_back(kRayleigh * pow(lambda, -4)); mie_scattering.push_back(mie * kMieSingleScatteringAlbedo); mie_extinction.push_back(mie); absorption_extinction.push_back(kMaxOzoneNumberDensity * kOzoneCrossSection[(l - kLambdaMin) / 10]); ground_albedo.push_back(0.1f); } m_model = new atmosphere::Model( wavelengths, solar_irradiance, kSunAngularRadius, kBottomRadius, kTopRadius, {rayleigh_density}, rayleigh_scattering, {mie_density}, mie_scattering, mie_extinction, kMiePhaseFunctionG, ozone_density, absorption_extinction, ground_albedo, max_sun_zenith_angle, 1000.0, 15, false, true); m_model->Init(m_config, m_textures); m_transmittance = new LLGLTexture; m_scattering = new LLGLTexture; m_mie_scattering = new LLGLTexture; m_transmittance->generateGLTexture(); m_transmittance->setAddressMode(LLTexUnit::eTextureAddressMode::TAM_CLAMP); m_transmittance->setFilteringOption(LLTexUnit::eTextureFilterOptions::TFO_BILINEAR); m_transmittance->setExplicitFormat(GL_RGB16F_ARB, GL_RGB, GL_FLOAT); m_transmittance->setTexName(m_textures.transmittance_texture); m_transmittance->setTarget(GL_TEXTURE_2D, LLTexUnit::TT_TEXTURE); m_scattering->generateGLTexture(); m_scattering->setAddressMode(LLTexUnit::eTextureAddressMode::TAM_CLAMP); m_scattering->setFilteringOption(LLTexUnit::eTextureFilterOptions::TFO_BILINEAR); m_scattering->setExplicitFormat(GL_RGB16F_ARB, GL_RGB, GL_FLOAT); m_scattering->setTexName(m_textures.transmittance_texture); m_scattering->setTarget(GL_TEXTURE_3D, LLTexUnit::TT_TEXTURE_3D); m_mie_scattering->generateGLTexture(); m_mie_scattering->setAddressMode(LLTexUnit::eTextureAddressMode::TAM_CLAMP); m_mie_scattering->setFilteringOption(LLTexUnit::eTextureFilterOptions::TFO_BILINEAR); m_mie_scattering->setExplicitFormat(GL_RGB16F_ARB, GL_RGB, GL_FLOAT); m_mie_scattering->setTexName(m_textures.transmittance_texture); m_mie_scattering->setTarget(GL_TEXTURE_3D, LLTexUnit::TT_TEXTURE_3D); }; LLAtmosphere::~LLAtmosphere() { // Cease referencing textures from atmosphere::model from our LLGLTextures wrappers for same. m_transmittance->setTexName(0); m_scattering->setTexName(0); m_mie_scattering->setTexName(0); delete m_model; m_model = nullptr; } LLGLTexture* LLAtmosphere::getTransmittance() const { return m_transmittance; } LLGLTexture* LLAtmosphere::getScattering() const { return m_scattering; } LLGLTexture* LLAtmosphere::getMieScattering() const { return m_mie_scattering; } GLhandleARB LLAtmosphere::getAtmosphericShaderForLink() const { return m_model ? m_model->GetShader() : 0; }