Fake shadows from clouds on top-down terrain on mobile - how ?

Is there an easy and relatively cheap way of having scrolling shadows cast by non-existing clouds on a static mesh terrain (comprised of many chunks, each having LODs) that has 4-way texture blending via vertex colors (top-down game) ?

Thanks

A panning cloud light function should work, have you tried one yet? Shouldn’t have any issues with the 4-way blend, but I haven’t tested it.

Here’s how to set it up:
.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/LightFunctions/index.html

and an example material:

EDIT: Just noticed the word mobile… :eek: if you use a stationary light it will work, just can’t be a static light.

No, I haven’t tried light functions yet. Stationary light won’t work in mobile VR - bogs down fps and shadows don’t work.

Isn’t there a way to add modulated texture to terrain’s material and pan it in time ?

Yes, you just take the cloud texture and map it using WorldPosition.XY divided by your scale. Then you just add your shadow tint by adding a VectorParameter and then you multiply it by another VectorParameter to control the upper bound and multiply that by your basecolor and/or specular. You can do a Min using this color and 1 to prevent over brightening things but I usually skip that step.