koobas.hobune.stream
Shimmering waves of wind-blown grass possible?
What would be the approach towards replicating that beautiful shimmering waves effect of grass blowing in the wind?
For example: Windy grass animated gif
Scotland grass blowing in wind
With Unity's standard billboard grass, it doesn't seem possible. The grass just stretches and the texture doesn't change to "flash" the grass blade's opposite side to cause the shimmering effect we see in real life.
Is such an effect possible with billboard grass? Perhaps repeatedly passing white "shadows" across an area would trick the eye? But how to cast white shadow? The shadow would have to brighten an area, not darken it. And could this trick be done on a flat surface?
For example, a distant green hill with no grass rendered due to distance, would have white shimmering waves move across it randomly. At a distance it would look like grass blowing in the wind. Like how cartoon artists would do.
Perhaps volumetric grass is the only way? Of course that is expensive.
Sorry for the wordy question. Thank you.
You could use noise in a vertex shader to displace the top vertexes of the billboards. That way they wouldn't all get displaced the same amount the same direction at the same time, but the noise function (with traveling offsets) would produce a nice rolling effect.
Thank you for the response.
Ins$$anonymous$$d of using each billboard, would it be possible to bound the upper portion of a grass field within a 3 dimensional "box" of noise? The noise box would only affect the grass. No characters or objects entering the grass field would have the noise affect them.
Somehow, is it possible to make a box that is Perlin noise, for example, and make that noise affect something within it? Or is noise limited to flat planes (thus limiting me to messing with grass billboards)?
Hard to articulate, so here's a quick sketch of what I mean:
