Gradient map in frame buffer?

[DPS]

Is there a way I could create a gradient map in the frame buffer so that I could map the luminance of my render to four values?

black, 33%, 67%, white.

Not sure if LUTs can do this? It?s more of a diagnostic tool and would be good to be able to toggle on off.

[nikolay.kusht]

I am not quite sure what exactly are you trying to achieve. Could you give us more details and perhaps some examples of the results that you are looking for.

[Vizioen]

What about using the background image?

[DPS]

I'm after something that will allow me to simplify my images to four values



I was able to do something similar by creating this gradient map in PS and then saving out a LUT to use in the VR frame buffer however there was an issue - I think something to do with the gamma - I had four values but their distribution was not correct. In PS gradient maps don't work in 32bit and I had created the LUT from a 16bit file PS file. I tried adding/removing a 2.2 curve in PS and saved out multiple LUTS but I was unable to get the same results between the frame buffer and my 16 bit PS file.

[nikolay.kusht]

So we came up with two ideas of how you could achieve those results:

1. You could use VRayExtraTex render element with Falloff maps set to "Shadow/Light" type. I am attching you a simple test scene.



2. Another way would be to use the VFB Color Corrections - Saturation and Curve(see the screen shots). You could also save the corrections to .cube file (Globals>Save) and load them later as LUT correction.