Adding Color map type inputs and outputs to a GPU node

You can create new custom node inputs and outputs that support color maps.

Right-click in an open custom node graph and select Edit > Create node > New custom node > Inputs or Outputs and choose Color map.

Example: This node has a Color map input named Input and a Color map output named Output.

Handling colors

In the script, to get the color of the current point of a color map, use the following syntax to declare a Color type variable:

// Declaration of a Color type variable and getting the color of the current point
Color C = Input

From a Color type variable, it is possible to retrieve the R, G, and B channels using the Red, Green, and Blue functions:

// Store the channels into 3 different variables
r = Red(c)
g = Green(c)
b = Blue(c)

The r, g, b variables can now be updated.

To store the result in the output color map, use the Color function. It uses three parameters and returns a Color value.

//Store into the output color map
Output = Color(r,g,b)

Example of script converting a color map into gray levels

Color col = Input

r = Red(col)
g = Green(col)
b = Blue(col) 

brightness = 0.3 * r + 0.59 * g + 0.11 * b 

coef = Intensity / 100
rFinal = (1 - coef) * r + coef * brightness
gFinal = (1 - coef) * g + coef * brightness
bFinal = (1 - coef) * b + coef * brightness 

Output = Color(rFinal, gFinal, bFinal)

Note: Do not name a variable "color" as this will conflit with the Color function.

Note: When the "Can access other points" option is used, the value of an input color map's point will be retrieved with syntax Input[dx,dy] instead of Input, which is the same as for terrain or mask inputs.

Updating a terrain color map

When using a terrain input and output, it is possible to update the terrain color map when present.
To get the input or output terrain's color map, just suffix its name with _ColorMap.

For example, if the input terrain's name is Input, its color map is named Input_ColorMap.
If the output terrain's name is Output, its color map is named Output_ColorMap.

Example of script modifying a terrain and its color map:

// Add 100 meters to the elevation
Output = Input + 100 

// Only keep the red channel
Color c = Input_ColorMap
Output_ColorMap = Color(Red(c), 0, 0)

If the input terrain has no color map, the instructions about the color maps are ignored at runtime.

Mixing different input and output types

It is possible to define different types for the input and the output.

This node has a Color map input and a Mask output.

With the following script, you create a mask from the input color map's red channel.

Output = Red(Input)

In this example, the node has a Mask input and a Color map output.

With the following script, you create a color map from the red channel, which contains the mask value.

Output = Color(Input,0,0)

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