Fix client terrain crashes and performance

[dragonblocks_alpha.git] / src / server / tree_physics.c

diff --git a/src/server/tree_physics.c b/src/server/tree_physics.c
index 03c672682f9b16c8ed9c2c2c37ee716aaedb36a1..7db6a107c701ad05307abbe165e90fe565b44980 100644 (file)
--- a/src/server/tree_physics.c
+++ b/src/server/tree_physics.c
@@ -1,3 +1,4 @@
+#include <assert.h>
 #include <dragonstd/array.h>
 #include <dragonstd/list.h>
 #include <dragonstd/tree.h>
@@ -42,7 +43,7 @@ static int cmp_chunk(const TerrainChunk *chunk, const v3s32 *pos)
 
 static void unlock_chunk(TerrainChunk *chunk)
 {
-       pthread_mutex_unlock(&chunk->mtx);
+       pthread_rwlock_unlock(&chunk->lock);
 }
 
 static void init_search_node(DepthSearchNode *search_node, CheckTreeArg *arg)
@@ -55,7 +56,7 @@ static void init_search_node(DepthSearchNode *search_node, CheckTreeArg *arg)
 
        // if not found in cache, get it from server_terrain and lock it
        if (!chunk) {
-               chunk = terrain_get_chunk(server_terrain, chunkp, false);
+               chunk = terrain_get_chunk(server_terrain, chunkp, CHUNK_MODE_PASSIVE);
 
                // check if chunk is unloaded
                if (!chunk) {
@@ -66,8 +67,8 @@ static void init_search_node(DepthSearchNode *search_node, CheckTreeArg *arg)
                        return;
                }
 
-               // try to obtain the chunk mutex
-               int lock_err = pthread_mutex_lock(&chunk->mtx);
+               // try to obtain the chunk lock
+               int lock_err = pthread_rwlock_wrlock(&chunk->lock);
 
                // a deadlock might occur because of the order the chunks are locked
                if (lock_err == EDEADLK) {
@@ -79,17 +80,11 @@ static void init_search_node(DepthSearchNode *search_node, CheckTreeArg *arg)
 
                        // done
                        return;
-               } else if (lock_err != 0) {
-                       // a different error has occured while trying to obtain the lock
-                       // this should never happen
-
-                       // print error message
-                       fprintf(stderr, "[error] failed to lock terrain chunk mutex\n");
-
-                       // exit program
-                       abort();
                }
 
+               // assert that no different error has occured while trying to obtain the lock
+               assert(lock_err == 0);
+
                // insert chunk into cache
                tree_add(&arg->chunks, &chunk->pos, chunk, &cmp_chunk, NULL);
        }
@@ -239,7 +234,7 @@ static bool check_tree(v3s32 root, Array *positions, Array *chunks)
 
        - select neighbor nodes that are leaves or wood
        - in every iteration, select only the nodes that belong to the same tree (have the same root)
-       - in every iteration, keep the mutexes of the chunks the selected nodes belong to locked
+       - in every iteration, keep the chunks the selected nodes belong to locked
        - skip nodes that don't match the currently selected root, process them in a later iteration
 */
 void tree_physics_check(v3s32 center)
@@ -276,7 +271,7 @@ void tree_physics_check(v3s32 center)
 
                        // get chunk
                        v3s32 offset;
-                       TerrainChunk *chunk = terrain_get_chunk_nodep(server_terrain, pos, &offset, false);
+                       TerrainChunk *chunk = terrain_get_chunk_nodep(server_terrain, pos, &offset, CHUNK_MODE_PASSIVE);
                        if (!chunk)
                                continue;
 
@@ -284,8 +279,9 @@ void tree_physics_check(v3s32 center)
                        bool locked_before = array_idx(&chunks, &chunk) != -1;
 
                        // lock if not locked
+                       // fixme: a deadlock can happen here lol
                        if (!locked_before)
-                               terrain_lock_chunk(chunk);
+                               assert(pthread_rwlock_wrlock(&chunk->lock) == 0);
 
                        // now that chunk is locked, actually get node
                        TerrainNode *node = &chunk->data[offset.x][offset.y][offset.z];
@@ -313,10 +309,10 @@ void tree_physics_check(v3s32 center)
                                        // remember index was selected
                                        selected[i] = true;
 
-                                       // don't run rest of loop body: don't unlock chunk mutex
+                                       // don't run rest of loop body to not unlock chunk
                                        continue;
                                } else {
-                                       // doesn't match selected root: mark as skipped
+                                       // if it doesn't match selected root, mark as skipped
                                        skipped = true;
                                        dirs[i] = false;
                                }
@@ -324,7 +320,7 @@ void tree_physics_check(v3s32 center)
 
                        // only unlock if it wasn't locked before
                        if (!locked_before)
-                               pthread_mutex_unlock(&chunk->mtx);
+                               pthread_rwlock_unlock(&chunk->lock);
                }
 
                if (selected_root) {