1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
|
/**
* @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<atmosphere::DensityProfileLayer> 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<double> wavelengths;
std::vector<double> solar_irradiance;
std::vector<double> rayleigh_scattering;
std::vector<double> mie_scattering;
std::vector<double> mie_extinction;
std::vector<double> absorption_extinction;
std::vector<double> ground_albedo;
for (int l = kLambdaMin; l <= kLambdaMax; l += 10)
{
double lambda = static_cast<double>(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, 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, 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, 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;
}
GLuint LLAtmosphere::getAtmosphericShaderForLink() const
{
return m_model ? m_model->GetShader() : 0;
}
|
