diff options
Diffstat (limited to '')
-rw-r--r-- | src/serverenvironment.cpp | 85 | ||||
-rw-r--r-- | src/serverenvironment.h | 3 |
2 files changed, 88 insertions, 0 deletions
diff --git a/src/serverenvironment.cpp b/src/serverenvironment.cpp index 320042e19..6ef56efc8 100644 --- a/src/serverenvironment.cpp +++ b/src/serverenvironment.cpp @@ -1066,6 +1066,91 @@ bool ServerEnvironment::swapNode(v3s16 p, const MapNode &n) return true; } +u8 ServerEnvironment::findSunlight(v3s16 pos) const +{ + // Directions for neighbouring nodes with specified order + static const v3s16 dirs[] = { + v3s16(-1, 0, 0), v3s16(1, 0, 0), v3s16(0, 0, -1), v3s16(0, 0, 1), + v3s16(0, -1, 0), v3s16(0, 1, 0) + }; + + const NodeDefManager *ndef = m_server->ndef(); + + // found_light remembers the highest known sunlight value at pos + u8 found_light = 0; + + struct stack_entry { + v3s16 pos; + s16 dist; + }; + std::stack<stack_entry> stack; + stack.push({pos, 0}); + + std::unordered_map<s64, s8> dists; + dists[MapDatabase::getBlockAsInteger(pos)] = 0; + + while (!stack.empty()) { + struct stack_entry e = stack.top(); + stack.pop(); + + v3s16 currentPos = e.pos; + s8 dist = e.dist + 1; + + for (const v3s16& off : dirs) { + v3s16 neighborPos = currentPos + off; + s64 neighborHash = MapDatabase::getBlockAsInteger(neighborPos); + + // Do not walk neighborPos multiple times unless the distance to the start + // position is shorter + auto it = dists.find(neighborHash); + if (it != dists.end() && dist >= it->second) + continue; + + // Position to walk + bool is_position_ok; + MapNode node = m_map->getNode(neighborPos, &is_position_ok); + if (!is_position_ok) { + // This happens very rarely because the map at currentPos is loaded + m_map->emergeBlock(neighborPos, false); + node = m_map->getNode(neighborPos, &is_position_ok); + if (!is_position_ok) + continue; // not generated + } + + const ContentFeatures &def = ndef->get(node); + if (!def.sunlight_propagates) { + // Do not test propagation here again + dists[neighborHash] = -1; + continue; + } + + // Sunlight could have come from here + dists[neighborHash] = dist; + u8 daylight = node.param1 & 0x0f; + + // In the special case where sunlight shines from above and thus + // does not decrease with upwards distance, daylight is always + // bigger than nightlight, which never reaches 15 + int possible_finlight = daylight - dist; + if (possible_finlight <= found_light) { + // Light from here cannot make a brighter light at currentPos than + // found_light + continue; + } + + u8 nightlight = node.param1 >> 4; + if (daylight > nightlight) { + // Found a valid daylight + found_light = possible_finlight; + } else { + // Sunlight may be darker, so walk the neighbours + stack.push({neighborPos, dist}); + } + } + } + return found_light; +} + void ServerEnvironment::clearObjects(ClearObjectsMode mode) { infostream << "ServerEnvironment::clearObjects(): " diff --git a/src/serverenvironment.h b/src/serverenvironment.h index af742e290..cfd5b8f3e 100644 --- a/src/serverenvironment.h +++ b/src/serverenvironment.h @@ -322,6 +322,9 @@ public: bool removeNode(v3s16 p); bool swapNode(v3s16 p, const MapNode &n); + // Find the daylight value at pos with a Depth First Search + u8 findSunlight(v3s16 pos) const; + // Find all active objects inside a radius around a point void getObjectsInsideRadius(std::vector<ServerActiveObject *> &objects, const v3f &pos, float radius, std::function<bool(ServerActiveObject *obj)> include_obj_cb) |