study-waves-01.curv

let 

EPSILON = 0.001;

between (v,a,b) = 1 - smoothstep(a-EPSILON,a+EPSILON,v) + smoothstep(b-EPSILON,b+EPSILON,v);
prel    (v,a,b) = (v - a)/(b - a);
scale   (v,a,b) = lerp(b[0],b[1],prel(v,a[0],a[1]));
hash     x      = frac(sin(x)*100000.0);

wave (x,y,z,t) = let
  row       = floor(x/2);
  k         = hash(row);
  phase     = lerp(0,20,k);
  amplitude = lerp(2,6,k);
  frequency = lerp(10,20,k)
in scale(
    cos(scale(phase + y,[0,frequency],[0,2*pi]))+1,
    [-1,1], [0, amplitude]
)

in

intersection (
  box {zmin:0, zmax:5, xmin:-10, xmax:10, ymin:-10, ymax:10},
  make_shape {
    dist (x,y,z,t) : let 
    h = wave (x,y,z,t);
    in max(0,z - h) + between(mod(x,2),0,1.5),
    is_2d  : false,
    is_3d  : true
  }
)

// EOF - vim: ts=2 sw=2 et syn=javascript