deferred block updates: falling sand

include/globals.h

@@ -74,6 +74,10 @@
 // Determines the fixed amount of memory allocated to blocks
 #define MAX_BLOCK_CHANGES 20000
 
+// How many "deferred" (happen at a later time than triggered) block updates to store.
+// Determines the fixed amount of memory allocated to that list
+#define MAX_DEFERRED_BLOCK_UPDATES 64
+
 // If defined, writes and reads world data to/from disk (or flash).
 // This is a synchronous operation, and can cause performance issues if
 // frequent random disk access is slow. Data is still stored in and
@@ -195,6 +199,13 @@ typedef struct {
   uint8_t block;
 } BlockChange;
 
+typedef struct {
+  short x;
+  short z;
+  uint8_t y;
+  uint8_t awaitTicks;
+} DeferredBlockUpdate;
+
 #pragma pack(push, 1)
 
 typedef struct {
@@ -267,6 +278,11 @@ typedef struct {
 extern BlockChange block_changes[MAX_BLOCK_CHANGES];
 extern int block_changes_count;
 
+extern DeferredBlockUpdate deferred_block_updates[MAX_DEFERRED_BLOCK_UPDATES];
+extern int deferred_block_updates_count;
+extern uint8_t is_processing_deferred_block_updates;
+extern uint8_t had_too_many_deferred_block_updates;
+
 extern PlayerData player_data[MAX_PLAYERS];
 extern int player_data_count;