Huge LBM lookup performance improvement on mapblock loading (#7195)

* Huge LBM lookup performance improvement on mapblock loading

diff --git a/src/serverenvironment.cpp b/src/serverenvironment.cpp
index 8a66d4dfa34df140986fbf73b399167308e4699e..be1ddd7f0e4f205b2ee4c87ce637742ed705fee9 100644 (file)
--- a/src/serverenvironment.cpp
+++ b/src/serverenvironment.cpp
@@ -262,16 +262,25 @@ void LBMManager::applyLBMs(ServerEnvironment *env, MapBlock *block, u32 stamp)
        MapNode n;
        content_t c;
        lbm_lookup_map::const_iterator it = getLBMsIntroducedAfter(stamp);
-       for (pos.X = 0; pos.X < MAP_BLOCKSIZE; pos.X++)
-               for (pos.Y = 0; pos.Y < MAP_BLOCKSIZE; pos.Y++)
-                       for (pos.Z = 0; pos.Z < MAP_BLOCKSIZE; pos.Z++)
-                       {
-                               n = block->getNodeNoEx(pos);
-                               c = n.getContent();
-                               for (LBMManager::lbm_lookup_map::const_iterator iit = it;
-                                       iit != m_lbm_lookup.end(); ++iit) {
-                                       const std::vector<LoadingBlockModifierDef *> *lbm_list =
-                                               iit->second.lookup(c);
+       for (; it != m_lbm_lookup.end(); ++it) {
+               // Cache previous version to speedup lookup which has a very high performance
+               // penalty on each call
+               content_t previous_c{};
+               std::vector<LoadingBlockModifierDef *> *lbm_list = nullptr;
+
+               for (pos.X = 0; pos.X < MAP_BLOCKSIZE; pos.X++)
+                       for (pos.Y = 0; pos.Y < MAP_BLOCKSIZE; pos.Y++)
+                               for (pos.Z = 0; pos.Z < MAP_BLOCKSIZE; pos.Z++) {
+                                       n = block->getNodeNoEx(pos);
+                                       c = n.getContent();
+
+                                       // If content_t are not matching perform an LBM lookup
+                                       if (previous_c != c) {
+                                               lbm_list = (std::vector<LoadingBlockModifierDef *> *)
+                                                       it->second.lookup(c);
+                                               previous_c = c;
+                                       }
+
                                        if (!lbm_list)
                                                continue;
                                        for (std::vector<LoadingBlockModifierDef *>::const_iterator iit =
@@ -279,7 +288,7 @@ void LBMManager::applyLBMs(ServerEnvironment *env, MapBlock *block, u32 stamp)
                                                (*iit)->trigger(env, pos + pos_of_block, n);
                                        }
                                }
-                       }
+       }
 }
 
 /*