Chromakey++

I adapted a green-screen shader from shadertoy.com for this chromakey user actor.

Original shadertoy code can be found here https://www.shadertoy.com/view/llBGWc (by jackdavenport, posted on 30 / 05 / 2015)

Some notes on its use:

• It doesn’t take changing a number much to get a big effect.
• The padding number (padd) may not ever need to be much over the .05 default.
• The threshold doesn’t need to be very big either for a large effect.
• The colour numbers represent how much of that colour is being keyed out of the source image. So if Red and Blue are at 0 and Green is at 1 then it would be set up for green-screening. (The default setting it comes in up with I believe.)
• You may find adding an HSL and/or a contrast actor between your source and this actor may help you tune out any green fuzzy bits in your key.