An LUT or Lookup Table is a way of mapping input values to output values via sampling a [[StaticTexture3D_(Component)|3D Texture]]. This 3D table of values allows for any arbitrary function to be applied to an input.
An LUT or Lookup Table is a way of mapping input values to output values via sampling a [[Component:StaticTexture3D|3D Texture]]. This 3D table of values allows for any arbitrary function to be applied to an input.
How the sampling works is that it takes a color behind it (for example, a magenta color) and maps it's RGB values to a 0-1 [[Type:Float3|Float3]] as XYZ, it then samples the provided 3D texture at point XYZ multipled by the texture's size, and uses the pixel's color as the result which is applied to what the user sees through this material.
For more info on how pixels are arranged on a 3D texture and can be retrieved using an [[Type:Int3|Int3]], see [[Component:StaticTexture3D|3D Texture]].
An LUT is commonly constructed via 2D slices of a [[StaticTexture3D_(Component)|3D Texture]]. These slices represent XY planes of incremental Z coordinates ranging from 0 to 1. This can either be packed into a single 2D image, or imported as multiple 2D images in a folder where each slice is alphabetically organized.
Currently the maximum packed 2D image that the importer detects as a valid LUT is 1024x32. In this orientation there are 32 total cells arranged as 32x32 pixel sub images. A 1:1 mapping LUT which simply maps its inputs directly to the same value on its outputs is shown below which demonstrates the coordinate system:
* The '''Red''' channel increases constantly from 0 to 1 from left to right within each cell and repeats.
[[File:LUT_BaseLinear_RED.png|center|alt=Linear LUT Red Channel|Linear LUT Red channel|thumb|800x800px]]
* The '''Green''' channel linearly increases from the top to bottom.
[[File:LUT_BaseLinear_GREEN.png|center|alt=Linear LUT Green Channel|Linear LUT Green channel|thumb|800x800px]]
* The '''Blue''' channel increases step wise within each cell itself, the first cell being all 0, and the last cell is all 1.
[[File:LUT_BaseLinear_BLUE.png|center|alt=Linear LUT Blue Channel|Linear LUT Blue channel|thumb|800x800px]]
The mapping function of an LUT takes an input RGB value and then samples the 3D Texture at that corresponding coordinate to find the output RGB value, using the [[StaticTexture3D_(Component)|3D Texture]]'s [[Type:TextureFilterMode|Filter Mode]] and [[Type:TextureWrapMode|Wrap Mode]] to resolve how intermediate values work.
The mapping function of an LUT takes an input RGB value and then samples the 3D Texture at that corresponding coordinate to find the output RGB value, using the [[StaticTexture3D_(Component)|3D Texture]]'s [[Type:TextureFilterMode|Filter Mode]] and [[Type:TextureWrapMode|Wrap Mode]] to resolve how intermediate values work.
An LUT or Lookup Table is a way of mapping input values to output values via sampling a 3D Texture. This 3D table of values allows for any arbitrary function to be applied to an input.
How the sampling works is that it takes a color behind it (for example, a magenta color) and maps it's RGB values to a 0-1 Float3 as XYZ, it then samples the provided 3D texture at point XYZ multipled by the texture's size, and uses the pixel's color as the result which is applied to what the user sees through this material.
For more info on how pixels are arranged on a 3D texture and can be retrieved using an Int3, see 3D Texture.
If true, integrating this asset (e.g. processing procedural assets) gets higher priority than assets with this flag off. An example is user laser procedural meshes.
The mapping function of an LUT takes an input RGB value and then samples the 3D Texture at that corresponding coordinate to find the output RGB value, using the 3D Texture's Filter Mode and Wrap Mode to resolve how intermediate values work.
