Add Titan atmosphere, increase scale height for Venus (closes #922)

data/assets/scene/solarsystem/planets/earth/atmosphere.asset

@@ -24,7 +24,7 @@ local Atmosphere = {
         Scattering = { 5.8E-3, 13.5E-3, 33.1E-3 },
         -- In Rayleigh scattering, the coefficients of absorption and scattering are the same.
       },
-      -- Thichkness of atmosphere if its density were uniform, in Km
+      -- Thickness of atmosphere if its density were uniform, in Km
       H_R = 8.0
     },
     --[[

data/assets/scene/solarsystem/planets/mars/atmosphere.asset

@@ -24,7 +24,7 @@ local Atmosphere = {
           -- In Rayleigh scattering, the coefficients of 
           -- absorption and scattering are the same.
         },
-    -- Thichkness of atmosphere if its density were uniform, in Km
+      -- Thickness of atmosphere if its density were uniform, in Km
         H_R = 10.43979
       },
       -- Default

data/assets/scene/solarsystem/planets/saturn/major_moons.asset

@@ -6,6 +6,7 @@ asset.require('./mimas/mimas')
 asset.require('./rhea/rhea')
 asset.require('./tethys/tethys')
 asset.require('./titan/titan')
+asset.require('./titan/atmosphere')
 
 
 asset.meta = {

data/assets/scene/solarsystem/planets/saturn/titan/atmosphere.asset

@@ -0,0 +1,58 @@
+local transforms = asset.require('./titan')
+local assetHelper = asset.require('util/asset_helper')
+
+local Atmosphere = {
+  Identifier = "TitanAtmosphere",
+  Parent = transforms.Titan.Identifier,
+  Renderable = {
+    Type = "RenderableAtmosphere",
+    -- Atmosphere radius in Km
+    AtmosphereHeight = 2666.0 - 2576.0,
+    PlanetRadius = 2576.0,
+    PlanetAverageGroundReflectance = 0.1,
+    GroundRadianceEmission = 0.9,
+    SunIntensity = 6.9,
+    Rayleigh = {
+      Coefficients = {
+        -- Wavelengths are given in 10^-9m
+        Wavelengths = { 680, 550, 440 },
+        -- Reflection coefficients are given in km^-1
+        Scattering = { 5.349578367831898E-3, 12.65595939366191E-3, 31.331782953393245E-3 },
+      },
+      -- Thickness of atmosphere if its density were uniform, in Km
+      H_R = 20.0
+    },
+    Mie = {
+        Coefficients = {
+          -- Reflection coefficients are given in km^-1
+          Scattering = { 5e-3, 12e-3, 80e-3 },
+          -- Extinction coefficients are a fraction of the Mie coefficients
+          Extinction = { 4.0e-3/0.37, 4.0e-3/0.37, 4.0e-3/0.37 }
+        },
+        -- Height scale (atmosphere thickness for constant density) in Km
+        H_M = 14.85,
+        -- Mie Phase Function Value (G e [-1.0, 1.0]. If G = 1.0, Mie phase function = Rayleigh Phase Function)
+        G = -0.52
+    },
+    Debug = {
+        PreCalculatedTextureScale = 1.0,
+        SaveCalculatedTextures = false
+    }
+  },
+  GUI = {
+    Name = "Titan Atmosphere",
+    Path = "/Solar System/Planets/Saturn/Moons/Titan"
+  }
+}
+
+assetHelper.registerSceneGraphNodesAndExport(asset, { Atmosphere })
+
+asset.meta = {
+  Name = "Titan Atmosphere",
+  Version = "1.0",
+  Description = [[ RenderableAtmosphere for Titan.]],
+  Author = "OpenSpace Team",
+  URL = "http://openspaceproject.com",
+  License = "MIT license",
+  Identifiers = { "TitanAtmosphere" }
+}

data/assets/scene/solarsystem/planets/venus/atmosphere.asset

@@ -23,8 +23,9 @@ local Atmosphere = {
           -- In Rayleigh scattering, the coefficients of 
           -- absorption and scattering are the same.
       },
-      -- Thichkness of atmosphere if its density were uniform, in Km
-      H_R = 3.53
+      -- Thickness of atmosphere if its density were uniform, in Km
+      H_R = 15.9 -- from https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html
+      -- H_R = 3.53
     },
     -- Default
     Mie = {

modules/atmosphere/rendering/renderableatmosphere.cpp

@@ -253,18 +253,18 @@ RenderableAtmosphere::RenderableAtmosphere(const ghoul::Dictionary& dictionary)
     , _atmosphereHeight(AtmosphereHeightInfo, 60.f, 0.1f, 99.0f)
     , _groundAverageReflectance(AverageGroundReflectanceInfo, 0.f, 0.f, 1.f)
     , _groundRadianceEmission(GroundRadianceEmittioninfo, 0.f, 0.f, 1.f)
-    , _rayleighHeightScale(RayleighHeightScaleInfo, 0.f, 0.1f, 20.f)
+    , _rayleighHeightScale(RayleighHeightScaleInfo, 0.f, 0.1f, 50.f)
     , _rayleighScatteringCoeff(
         RayleighScatteringCoeffInfo,
         glm::vec3(0.f), glm::vec3(0.00001f), glm::vec3(0.1f)
     )
     , _ozoneEnabled(OzoneLayerInfo, false)
-    , _ozoneHeightScale(OzoneHeightScaleInfo, 0.f, 0.1f, 20.f)
+    , _ozoneHeightScale(OzoneHeightScaleInfo, 0.f, 0.1f, 50.f)
     , _ozoneCoeff(
         OzoneLayerCoeffInfo,
         glm::vec3(0.f), glm::vec3(0.00001f), glm::vec3(0.001f)
     )
-    , _mieHeightScale(MieHeightScaleInfo, 0.f, 0.1f, 20.f)
+    , _mieHeightScale(MieHeightScaleInfo, 0.f, 0.1f, 50.f)
     , _mieScatteringCoeff(
         MieScatteringCoeffInfo,
         glm::vec3(0.004f), glm::vec3(0.00001f), glm::vec3(1.f)
@@ -392,33 +392,12 @@ void RenderableAtmosphere::deinitializeGL() {
 
 void RenderableAtmosphere::initializeGL() {
     _deferredcaster = std::make_unique<AtmosphereDeferredcaster>();
-    _deferredcaster->setAtmosphereRadius(_planetRadius + _atmosphereHeight);
-    _deferredcaster->setPlanetRadius(_planetRadius);
-    _deferredcaster->setPlanetAverageGroundReflectance(_groundAverageReflectance);
-    _deferredcaster->setPlanetGroundRadianceEmittion(_groundRadianceEmission);
-    _deferredcaster->setRayleighHeightScale(_rayleighHeightScale);
-    _deferredcaster->enableOzone(_ozoneEnabled);
-    _deferredcaster->setOzoneHeightScale(_ozoneHeightScale);
-    _deferredcaster->setMieHeightScale(_mieHeightScale);
-    _deferredcaster->setMiePhaseConstant(_miePhaseConstant);
-    _deferredcaster->setSunRadianceIntensity(_sunIntensity);
-    _deferredcaster->setRayleighScatteringCoefficients(_rayleighScatteringCoeff);
-    _deferredcaster->setOzoneExtinctionCoefficients(_ozoneCoeff);
-    _deferredcaster->setMieScatteringCoefficients(_mieScatteringCoeff);
-    _deferredcaster->setMieExtinctionCoefficients(_mieExtinctionCoeff);
-    // TODO: Fix the ellipsoid nature of the renderable globe (JCC)
-    //_deferredcaster->setEllipsoidRadii(_ellipsoid.radii());
-    _deferredcaster->enableSunFollowing(_sunFollowingCameraEnabled);
-
-    _deferredcaster->setPrecalculationTextureScale(_preCalculatedTexturesScale);
-    if (_saveCalculationsToTexture)
-        _deferredcaster->enablePrecalculationTexturesSaving();
+    updateAtmosphereParameters();
 
     if (_shadowEnabled) {
         _deferredcaster->setShadowConfigArray(_shadowConfArray);
         // We no longer need it
         _shadowConfArray.clear();
-        _deferredcaster->setHardShadows(_hardShadowsEnabled);
     }
 
     _deferredcaster->initialize();
@@ -481,8 +460,14 @@ void RenderableAtmosphere::updateAtmosphereParameters() {
     _deferredcaster->setMieScatteringCoefficients(_mieScatteringCoeff);
     _deferredcaster->setMieExtinctionCoefficients(_mieExtinctionCoeff);
     _deferredcaster->enableSunFollowing(_sunFollowingCameraEnabled);
+    // TODO: Fix the ellipsoid nature of the renderable globe (JCC)
     //_deferredcaster->setEllipsoidRadii(_ellipsoid.radii());
 
+    _deferredcaster->setPrecalculationTextureScale(_preCalculatedTexturesScale);
+    if (_saveCalculationsToTexture) {
+        _deferredcaster->enablePrecalculationTexturesSaving();
+    }
+
     if (_shadowEnabled) {
         _deferredcaster->setHardShadows(_hardShadowsEnabled);
     }