UV distortion - smoke trail - seeking answers

https://youtu.be/YxrF4R_p4GM?t=14m26s (@14m26s)

we can see an atlas with a particular RGB image; it would seem scrolling green is used to distort one of the wisps trails

while the blue & red lerp

  1. degree of the distortion (none at the base, and more at the end)
  2. add a seamless noise texture for broken clouds on the end

and all this to create a single overdraw trail of smoke


it seemed simple visually, but i’m blocked with the math; I tried something ostensibly like …

U.offset = (Green * 2) - 1
(in a simple shader forge network)

what I visually imagined working just isn’t right. Can anyone send me down a smarter path?


Try this first,
Green channel scrolling up.
And offset the U and V of the “Green” texture’s UVs with a scrolling Cloud.

Example distortion (ignoring the panning/masking):

I don’t see the use of the R/B channel you mention.
You could mask the intensity algorithmically using the mesh V co-ords.

1 Like

!brilliant that gives me some ideas and raises some points on the visual

  • the smoke base moves like the pseudo-sine wave
  • accounts for texture on the smoke trail having motion

red can process as alpha (or vertex color which will also be used to tint)
but the video shows seamless texture cloud (no distortion) scrolling on the top half only, with falloff…

i’m imagining; Color += cloudTex * blue

just want to say thanks for sharing the video !!! great piece of information!!! sorry I cant help much ^^