A custom height field mask showing the eye-level visibility of each voxel. Most visible parts from any location on the terrain are highlighted red, rather hidden areas are marked blue.
// PARAMETERS
float lift = chf('lift');
float shorten = chf('shorten');
// SAMPLE POSITIONS
vector pos[] = detail(1, 'pos', 0);
// RAY ORIGINS
vector orig = v@P;
orig.y += f@height;
orig = minpos(1, orig);
orig.y += lift;
// RAYTRACING
int missed = 0;
foreach(vector p; pos){
vector dir = p - v@P;
float dist = length(dir);
dir = normalize(dir) * max(dist - shorten, 0.0);
int pr = intersect(1, orig, dir, set(0), set(0));
missed += pr < 0;
}
// OUTPUT
f@mask = missed / float(len(pos));
/*
GRID POINTS FOR DEBUGGING
int pt = addpoint(0, orig);
setpointattrib(0, 'hits', pt, missed, 'set');
*/
