void Mapgen::calcLighting(v3s16 nmin, v3s16 nmax) {
VoxelArea a(nmin, nmax);
bool block_is_underground = (water_level >= nmax.Y);
ScopeProfiler sp(g_profiler, "EmergeThread: mapgen lighting update", SPT_AVG);
//TimeTaker t("updateLighting");
// first, send vertical rays of sunshine downward
v3s16 em = vm->m_area.getExtent();
for (int z = a.MinEdge.Z; z <= a.MaxEdge.Z; z++) {
for (int x = a.MinEdge.X; x <= a.MaxEdge.X; x++) {
// see if we can get a light value from the overtop
u32 i = vm->m_area.index(x, a.MaxEdge.Y + 1, z);
if (vm->m_data[i].getContent() == CONTENT_IGNORE) {
if (block_is_underground)
continue;
} else if ((vm->m_data[i].param1 & 0x0F) != LIGHT_SUN) {
continue;
}
vm->m_area.add_y(em, i, -1);
for (int y = a.MaxEdge.Y; y >= a.MinEdge.Y; y--) {
MapNode &n = vm->m_data[i];
if (!ndef->get(n).sunlight_propagates)
break;
n.param1 = LIGHT_SUN;
vm->m_area.add_y(em, i, -1);
}
}
}
// now spread the sunlight and light up any sources
for (int z = a.MinEdge.Z; z <= a.MaxEdge.Z; z++) {
for (int y = a.MinEdge.Y; y <= a.MaxEdge.Y; y++) {
u32 i = vm->m_area.index(a.MinEdge.X, y, z);
for (int x = a.MinEdge.X; x <= a.MaxEdge.X; x++, i++) {
MapNode &n = vm->m_data[i];
if (n.getContent() == CONTENT_IGNORE ||
!ndef->get(n).light_propagates)
continue;
u8 light_produced = ndef->get(n).light_source & 0x0F;
if (light_produced)
n.param1 = light_produced;
u8 light = n.param1 & 0x0F;
if (light) {
lightSpread(a, v3s16(x, y, z + 1), light - 1);
lightSpread(a, v3s16(x, y + 1, z ), light - 1);
lightSpread(a, v3s16(x + 1, y, z ), light - 1);
lightSpread(a, v3s16(x, y, z - 1), light - 1);
lightSpread(a, v3s16(x, y - 1, z ), light - 1);
lightSpread(a, v3s16(x - 1, y, z ), light - 1);
}
}
}
}
//printf("updateLighting: %dms\n", t.stop());
}
void Mapgen::lightSpread(VoxelArea &a, v3s16 p, u8 light) {
if (light <= 1 || !a.contains(p))
return;
u32 vi = vm->m_area.index(p);
MapNode &nn = vm->m_data[vi];
light--;
// should probably compare masked, but doesn't seem to make a difference
if (light <= nn.param1 || !ndef->get(nn).light_propagates)
return;
nn.param1 = light;
lightSpread(a, p + v3s16(0, 0, 1), light);
lightSpread(a, p + v3s16(0, 1, 0), light);
lightSpread(a, p + v3s16(1, 0, 0), light);
lightSpread(a, p - v3s16(0, 0, 1), light);
lightSpread(a, p - v3s16(0, 1, 0), light);
lightSpread(a, p - v3s16(1, 0, 0), light);
}