diff --git a/builtin/game/constants.lua b/builtin/game/constants.lua
index d0b7c753c..56fca9289 100644
--- a/builtin/game/constants.lua
+++ b/builtin/game/constants.lua
@@ -4,14 +4,19 @@
 -- Constants values for use with the Lua API
 --
 
+-- mapnode.h
 -- Built-in Content IDs (for use with VoxelManip API)
 core.CONTENT_UNKNOWN = 125
 core.CONTENT_AIR     = 126
 core.CONTENT_IGNORE  = 127
 
+-- emerge.h
 -- Block emerge status constants (for use with core.emerge_area)
 core.EMERGE_CANCELLED   = 0
 core.EMERGE_ERRORED     = 1
 core.EMERGE_FROM_MEMORY = 2
 core.EMERGE_FROM_DISK   = 3
 core.EMERGE_GENERATED   = 4
+
+-- constants.h
+core.MAP_BLOCKSIZE = 16
diff --git a/builtin/game/forceloading.lua b/builtin/game/forceloading.lua
index 8c9fbf512..468572e6e 100644
--- a/builtin/game/forceloading.lua
+++ b/builtin/game/forceloading.lua
@@ -7,7 +7,7 @@ core.forceload_free_block = nil
 local blocks_forceloaded
 local total_forceloaded = 0
 
-local BLOCKSIZE = 16
+local BLOCKSIZE = core.MAP_BLOCKSIZE
 local function get_blockpos(pos)
 	return {
 		x = math.floor(pos.x/BLOCKSIZE),