koobas.hobune.stream
How to move vertices up/down randomly in shader.
Hello!
I have a plane and I'd like to adjust the y positions of the vertices in the shader. Actually moving them is simple enough, but I was wondering what the best way of getting the random values for heights was?
Would I need a random function inside the shader to get a value within a range?
Thanks
Hey, thanks for the reply! Sorry I was vague.
What I'm hoping to achieve is to modify a flat plane so that the vertices will move up and/or down in the y axis, giving it an uneven surface.
I am just using this:
// Vertex modifier
void vert (inout appdata_full v)
{
v.vertex.y += _Amount;
}
where _Amount will be the random value generated. With the function you provided, what float2 input should it take?
Thanks a lot!
Unless you want complete randomness you should probably use some kind of noise function such as perlin noise.
But for optimization purposes you should probably just use a texture as a heightmap to offset your verts!
Hey bud, Are you trying to scroll your texture with the shader or something like that ? You would be looking to do this in the Surf shader function
You could call to the _Time property and multiply it by a set of values based on the x and y you set it. yo could then effect them with random values passed into the vars holding the x and y values. I could go on. the code would look similar to this...
fixed yScrollValue = _ScrollYSpeed * _Time;
you might make _ScrollYSpeed an accessible parameter in the inspector for the shader allowing you to adjust/tweak it visually afterwards.
You could be looking for a a small function to run on a float in your code like so....
float randomNum(in float2 uv)
float2 noise = (frac(sin(dot(uv ,float2(12.9898,78.233)*2.0)) * 43758.5453));
return abs(noise.x + noise.y) * 0.5;
}
but without your code, who knows ? Then again, who even knows, if you are using Unitys shader language, Cg, HLSL ?
So... Could you possibly add in your shader code please, so we can get to the bottom of it faster for you.
Hope that helps some Take care Bud Gruffy
