How to change colours of RGB and Affect the colour of an object

[Stefan Cargoski]

Hi community.

Is there a way seperate objects of  R G B can be individual entities and affect one particular object like a colour picker.

https://tuneform.com/tools/color/rgb-color-creator

I have 3 rectangles RED GREEN BLUE, each has the Hue effect, and goes from 0 to 100. 

Red goes from black to Red 100%, Same for the Green and same for the Red.

This is what I'd like to ahieve if possible in AE, (and then also add some effects to it)

[Mylenium · Accepted solution]

Sure. You would apply a sampleImage() expression to fetch the color values and then create a formula to derive a mix color - whatever that is supposed to be. In your case you coulkd even directly grab the valuies from within the effect. After all, Ae has a built-in hslToRgb() method in its expression engine.

Mylenium

[Stefan Cargoski]

Hi Mylenium.

This seems like a hard one to do, any tutorials online for such a task?  I was about to post this as well in case its easier, because I'm confused with the reply you wrote.

I'm trying to pick whip the purple layer to the HUE values of the Red and Green Layers, so it can inherit its HUE values, so I can slide each colour independently.

[Mylenium]

It's not hard as far as the code goes, but color mixing itself could be tricky, given that just linearly blending colors often can yield unwanted intermediate colors like muddy greys. A simple averaging of two colors could be as trivial as 

normalize(add(colorA,colorB));

with the pertinent references to the color controls needing to be filled in. For three colors you simply use a second set of mix colors, then mix the normalized results again in a third step. in your case the already mentioned hslToRgb() or its revers rgbToHsl() may need to be inserted to get correct results on an effect such as Hue/ Saturation. the basic method I illustrated would directly work in e.g. a Fill effect/ shape layer fill.

Mylenium