Distance3f distance_line3(const float3 p, const float3 a, const float3 b) {
const float3 bma = b-a;
const float3 bma_u = fast_normalize(bma);
const float ab = fast_length(bma);
const float3 pma = p - a;
const float dotf = dot(pma, bma_u);
if (dotf < 0) {
Distance3f d = { fast_length(pma), a };
return d;
} else if (dotf > ab) {
Distance3f d = { fast_length(pma), b };
return d;
} else {
const float dist = fast_length(cross(pma, bma_u));
const float3 pi = a + (bma_u * dotf);
Distance3f d = { dist, pi };
return d;
}
}
Distance3i distance_geom3(
const int3 p, global const int* geometry, global const int3* verts) {
// Distance3i best = { INT_MAX, (int3)(0, 0, 0) };
Distance3i best = { INT_MAX, make_int3(0, 0, 0) };
const int num_tris = geometry[1];
const Triangle* tris = (Triangle*)(geometry+2);
for (int j = 0; j < num_tris; ++j) {
Triangle t = tris[j];
const int3 tri_verts[3] =
{ (verts[t.s[0]]),
(verts[t.s[1]]),
(verts[t.s[2]]) };
int3 set_verts[3];
const int num_unique = find_unique(tri_verts, set_verts);
if (num_unique == 3) {
best = min_pair3i(best, distance_trianglei(p, tri_verts));
} else {
// Degenerate triangle
if (num_unique == 1) {
// Degenerate to a point
int3 closest = tri_verts[0];
float3 closest_d = convert_float3(closest);
float3 p_d = convert_float3(p);
int dist = (int)(fast_length(p_d-closest_d)+0.5f);
best = min_pair3i(best, make_dist3(dist, closest));
} else {
// Degenerate to a line
int3 a = set_verts[0];
int3 b = set_verts[1];
Distance3f dist = distance_line3(convert_float3(p),
convert_float3(a),
convert_float3(b));
Distance3i disti = make_dist3(
// convert_int_rte(dist.d),
// convert_int3_rte(dist.p));
convert_int(dist.d),
convert_int3(dist.p));
best = min_pair3i(best, disti);
}
}
}
return best;
}
cuda_device friend T fast_distance(const vector4& v1, const vector4& v2) {
return fast_length(v1 - v2);
}
