RGB to HSV shader

Development Rendering
1

Hi,
I am trying to do a RGB to HSV color conversion for “hue shift” and other effects.

Here is my shader code:

0ff364b5b88855664f7313133d460b03a8299a22.jpeg
0ff364b5b88855664f7313133d460b03a8299a22.jpeg1920×1080 363 KB

For some reason the output is blocky (lower resolution) and the hue does not seem to be linear.
Has someone done this successfully? Any ideas whats wrong?

Here is a link to the algorithm.

Thanks for any help

2

Since you are working with textures this kind of code won’t work. Operations like If, frac and similar will break the texture filtering and mipmapping and therefore introduce various artifacts. Instead you should look for color conversions / hue rotations using a transform matrix and some trigonometry: Code: Affine HSV color manipulation

That being said, UE4 already comes with a material function called HueShift.