The Lookup component outputs whatever color it finds in its Source input at the coordinates specified by Lookup X and Lookup Y. When the coordinates are specified by constants, Lookup acts as a simple color picker, filling its entire output with the color it samples from the source input. When the coordinates are mapped by other components, Lookup can serve as a powerful tool for various image transformations. This is a map component, it can be located in the Transform category on the Components Bar. This component can output HDR colors.
Source: Map Input (HDR), Required
Provides the source image. This is a required input – in order to make Lookup work, this input must be connected. This input can accept HDR colors.
Lookup X and Y: Map Inputs (HDR)
These inputs define the coordinates of the lookup point. The way these coordinates are interpreted is defined by the XY Anchor input. Since Lookup X and Lookup Y are map inputs, their values can be controlled separately for different image areas by connecting a map component. These inputs can accept HDR colors.
Determines how the coordinate values supplied by Lookup X and Lookup Y inputs are interpreted. For more information, see How XY Anchor Works.
When a map component is connected to this input, the number of the selected list item is determined separately for different image areas by the HDR brightness level of the image supplied by that component. The item number is calculated as the brightness level rounded to the nearest integer: the brightness level of 0 to 0.5 corresponds to the first item, the level of 0.5 to 1.5 to the second item, and 1.5 to 2.5 to the third item. Out-of-range values are clipped, which corresponds to the last item of the list.
