#include <volume.vfl>
vector pos;
vector uvw;
intersect(1,@P,{0,1000,0},pos,uvw);
@height = -pos.y;

#include <volume.vfl>
vector pos = 0;
vector2 uv ;
float avg ;
for(int i = 0 ;i< 25;i++){
    uv = rand(i+0.2);
    sampledisk(pos.x,pos.y,uv.x,uv.y);
    pos *= vector(200);
    avg += (volumesample(0,0,@P+pos)-@height)/10;
    }
    
@height += avg;
@height += 20 *anoise(0.01*@P,2,0.5,0.5);

float v_turb(vector sample_point;
            float roughness;
            float lacunarity;
            int octaves 
            {
            float sum = 0;
            float weight = 1.0;
            vector samp_p = sample_point;
            
            for (int i=0;i<octaves +1;i++){
            sum += (noise(samp_p)-{0.5,0.5,0.5})*weight;
            samp_p *= lacunarity;
            weight *= roughness;
            }
            return sum;
            }
     
            
@height += 100*v_turb(@P*set(0.02,0,0.01),0.2,3,4);
float mask = length (@P);
mask = fit(mask,0,500,0,1);
mask = chramp("rap",mask);
@height*= mask;

vector pos;
vector uvw;
int hit;

hit = intersect(1,@P,{0,1000,0},pos,uvw);
if (hit != -1) {
    if (@height > pos.y) {
        @height = pos.y;
        }
    }

hit = intersect(1,@P,{0,-1000,0},pos,uvw);
if (hit != -1) {
    if (@height > pos.y) {
        @height = pos.y;
        }
    }