Feature/new stars rendering (#784)

* Physically-based star rendering.
 * New Tully Pic Galaxies speck file w/o Milky Way
 * Removed PSC from stars rendering.
 * Avoiding extra calculations during shading.
 * Removed bug in billboard maximum size code.
 * New method to get the current viewport resolution. Used e.g. when rendering stereo side-by-side configuration.
 * Same as stereo stars.
 * Improved configuration.
 * Stars camera orientation.
 * Separated changes in billboards.
 * Adde min size control.
 * Setting minimum size.
 * Changed eye position. Changed data array nome inside shaders to a more accurate representation of the data.
 * Billboards reflecting actual stars sizes.
 * Scaling stars size based on luminosity, Abs Mag and size.
 * Rendering to a texture instead of fragment calculation for each star.
 * Added default parameters, new configurations and updated parameters.
 * Updated speck file handling to reflect a more general specification.
 * Added apparent magnitude from the speck files.
 * Set correct star values values for Apogee and Galah
 * Changed position from vec4 to vec3 to save GPU memory.

data/assets/default.scene

@@ -10,6 +10,7 @@ asset.require('scene/solarsystem/planets/mars/moons/phobos')
 asset.require('scene/solarsystem/planets/mars/moons/deimos')
 asset.require('scene/solarsystem/dwarf_planets/pluto/system')
 assetHelper.requestAll(asset, 'scene/digitaluniverse')
+
 -- Load default key bindings applicable to most scenes
 asset.require('util/default_keybindings')
 asset.require('util/default_dashboard')

data/assets/scene/digitaluniverse/stars.asset

@@ -29,7 +29,11 @@ local stars = {
         Type = "RenderableStars",
         File = speck .. "/stars.speck",
         Texture = textures .. "/halo.png",
-        ColorMap = colorLUT .. "/colorbv.cmap"
+        --ShapeTexture = textures .. "/disc.png",
+        ColorMap = colorLUT .. "/colorbv.cmap",
+        MagnitudeExponent = 6.2,
+        SizeComposition = "Distance Modulus",
+        RenderMethod = "Texture Based" -- or PSF
     },
     GUI = {
         Path = "/Milky Way/Stars"

data/assets/scene/digitaluniverse/tully.asset

@@ -13,7 +13,7 @@ local speck = asset.syncedResource({
     Name = "Tully Speck Files",
     Type = "HttpSynchronization",
     Identifier = "digitaluniverse_tully_speck",
-    Version = 1
+    Version = 2
 })
 
 local tullyPoints = {

data/assets/scene/milkyway/gaia/apogee.asset

@@ -31,8 +31,11 @@ local gaia_abundance_apogee = {
         File = speck .. "/GaiaAbundApogee.speck",
         ColorOption = "Other Data",
         OtherData = "FeH",
-        ScaleFactor = 100,
+        MagnitudeExponent = 6.2,
+        SizeComposition = "Distance Modulus",
+        RenderMethod = "Texture Based",
         Texture = textures .. "/halo.png",
+        -- ShapeTexture = textures .. "/disc.png",
         ColorMap = colorLUT .. "/colorbv.cmap",
         OtherDataColorMap = colorLUT .. "/viridis.cmap",
         StaticFilter = -9999,

data/assets/scene/milkyway/gaia/galah.asset

@@ -30,9 +30,12 @@ local gaia_abundance_galah = {
         Enabled = false,
         File = speck .. "/GaiaAbundGalah.speck",
         Texture = textures .. "/halo.png",
+        -- ShapeTexture = textures .. "/disc.png",
+        MagnitudeExponent = 6.2,
+        SizeComposition = "Distance Modulus",
+        RenderMethod = "Texture Based",
         ColorOption = "Other Data",
         OtherData = "FeH",
-        ScaleFactor = 100,
         ColorMap = colorLUT .. "/colorbv.cmap",
         OtherDataColorMap = colorLUT .. "/viridis.cmap",
         StaticFilter = -9999,

data/assets/scene/milkyway/stars/denver.asset

@@ -29,7 +29,10 @@ local object = {
         Type = "RenderableStars",
         File = speck .. "/denver_stars.speck",
         Texture = textures .. "/halo.png",
-        ColorMap = colorLUT .. "/denver_colorbv.cmap"
+        ColorMap = colorLUT .. "/denver_colorbv.cmap",
+        MagnitudeExponent = 6.2,
+        SizeComposition = "Distance Modulus",
+        RenderMethod = "Texture Based" -- or PSF
     },
     GUI = {
         Name = "Stars (Denver)",