Of course, Photoshop Curves is a very powerful color grading tool. How do I do something similar using shaders?
How do I change input value to different output value of a color channel ??
Inigo Quilez has a great chapter on this in the book of shaders. It’s about “shaping functions” that can be used to generate or modify textures.
A super basic version of this in spark, is simply using the smooth step patch on a texture. It acts as an s-curve, just like in photoshop.
I ported the curve plotter from the book of shaders so you can use it directly in Spark. It’s a great way to visualize color adjustments.
Curve Plotter.arp (5.0 KB)
Related, here’s another patch that can be used to test color adjustments.
POP_ColorTester.arp (7.2 KB)