RenderableGalaxy

Inherits Renderable

Members

Name	Documentation	Type	Description	Optional
Points		Table	Table parameters	No
Volume		Table	Table parameters	No
AbsorptionMultiply	A unit-less scale factor for the probability of dust absorbing a light particle. The amount of absorption determines the spectrum of the light that is emitted from the galaxy	Double	Value of type ‘Double’	Yes
EmissionMultiply	A unit-less scale factor for the amount of light being emitted by dust in the galaxy	Double	Value of type ‘Double’	Yes
RaycastingShader	If this value is specified, the default raycasting shader is overwritten and the shader found at the provided location is used instead	File	Value of type ‘File’	Yes
Rotation	The internal rotation of the volume rendering in Euler angles	Vector3<double>	Value of type ‘Vector3’	Yes
StarRenderingEnabled	If this value is enabled, the point-based star rendering component of the galaxy rendering is turned on. Otherwise, the volume rendering is skipped	Boolean	Value of type ‘Boolean’	Yes
StarRenderingMethod	This value determines which rendering method is used for visualization of the stars	String	In list { Points, Billboards }	Yes
StepSizeInfo	Determines the distance between steps taken in the volume rendering. The lower the number is, the better the rendering looks, but also takes more computational resources to render	Double	Value of type ‘Double’	Yes
VolumeRenderingEnabled	If this value is enabled, the volume rendering component of the galaxy rendering is turned on. Otherwise, the volume rendering is skipped	Boolean	Value of type ‘Boolean’	Yes

Inherited members from Renderable

Name	Documentation	Type	Description	Optional
DimInAtmosphere	Enables/Disables if the object should be dimmed when the camera is in the sunny part of an atmosphere	Boolean	Value of type ‘Boolean’	Yes
Enabled	This setting determines whether this object will be visible or not	Boolean	Value of type ‘Boolean’	Yes
Opacity	This value determines the opacity of this renderable. A value of 0 means completely transparent	Double	In range: ( 0,1 )	Yes
RenderBinMode	This value specifies if the renderable should be rendered in the Background,Opaque, Pre/PostDeferredTransparency, or Overlay rendering step	String	In list { Background, Opaque, PreDeferredTransparent, PostDeferredTransparent, Overlay }	Yes
Tag	A single tag or a list of tags that this renderable will respond to when setting properties	Table, or String	Value of type ‘Table’, or Value of type ‘String’	Yes
Type	This tells the type of the renderable	String	Value of type ‘String’	Yes

Table parameters for Points

• Optional: No

Name	Documentation	Type	Description	Optional
EnabledPointsRatio	The ratio of point-like stars that are rendered to produce the overall galaxy image. At a value of 0, no stars are rendered, at a value of 1 all points contained in the dataset are rendered. The specific value chosen is a compromise between image fidelity and rendering performance	Double	Value of type ‘Double’	Yes
Filename		File	Value of type ‘File’	No
Texture		File	Value of type ‘File’	No

Table parameters for Volume

• Optional: No

Name	Documentation	Type	Description	Optional
Dimensions		Vector3<int>	Value of type ‘Vector3’	No
Downscale	This value sets the downscaling factor when rendering the current volume	Double	Value of type ‘Double’	Yes
Filename		File	Value of type ‘File’	No
Size		Vector3<double>	Value of type ‘Vector3’	No
Steps	This value set the number of integration steps during the raycasting procedure	Double	Value of type ‘Double’	Yes

Asset Examples

local transforms = asset.require("scene/solarsystem/sun/transforms")



local data = asset.resource({
  Name = "Milkyway Volume Data",
  Type = "HttpSynchronization",
  Identifier = "milkyway_volume_data",
  Version = 1
})


local KiloParsec = 3.086E19

local MilkyWayVolume = {
  Identifier = "MilkyWayVolume_CustomShader",
  Parent = transforms.SolarSystemBarycenter.Identifier,
  Transform = {
    Translation = {
      Type = "StaticTranslation",
      -- The center of the Milky Way is approximately 8 kiloparsec from the Sun.
      -- The x-axis of galactic coordinates points from the sun towards the center
      -- of the galaxy.
      Position = { 8 * KiloParsec, 0, 0 }
    }
  },
  Renderable = {
    Type = "RenderableGalaxy",
    StepSize = 0.01,
    AbsorptionMultiply = 200,
    EmissionMultiply = 250,
    Rotation = { math.pi, 3.1248, 4.45741 },
    RaycastingShader = asset.resource("galaxyraycast.glsl"),
    Volume = {
      Type = "Volume",
      Filename = data .. "MilkyWayRGBAVolume1024x1024x128.raw",
      Dimensions = { 1024, 1024, 128 },
      Size = { 1.2E21, 1.2E21, 0.15E21 },
      Downscale = 0.4
    },
    Points = {
      Type = "Points",
      Filename = data .. "MilkyWayPoints.off",
      EnabledPointsRatio = 0.3,
      Texture = data .. "halo.png"
    }
  },
  GUI = {
    Path = "/Milky Way",
    Name = "Milky Way Volume (Custom Shader)",
    Description = "Volumetric rendering of Milky Way galaxy based on simulation from NAOJ"
  }
}


asset.onInitialize(function()
  openspace.addSceneGraphNode(MilkyWayVolume)
end)

asset.onDeinitialize(function()
  openspace.removeSceneGraphNode(MilkyWayVolume)
end)

asset.export(MilkyWayVolume)



asset.meta = {
  Name = "Milky Way Volume",
  Version = "1.1",
  Description = [[Volumetric rendering of Milky Way galaxy based on simulations from "
  "NAOJ with a custom shader]],
  Author = "OpenSpace Team",
  URL = "http://openspaceproject.com",
  License = "MIT License"
}