Biome dust placement: Improve comments, re-order some lines

diff --git a/src/mapgen/mapgen.cpp b/src/mapgen/mapgen.cpp
index 6163d17afacb6427ee2a5e2ea796fc588f45f8cc..dcdaf82c2fd3a65fc499138797f5442d98f2b7b0 100644 (file)
--- a/src/mapgen/mapgen.cpp
+++ b/src/mapgen/mapgen.cpp
@@ -791,6 +791,10 @@ void MapgenBasic::dustTopNodes()
                if (biome->c_dust == CONTENT_IGNORE)
                        continue;
 
+               // Check if mapchunk above has generated, if so, drop dust from 16 nodes
+               // above current mapchunk top, above decorations that will extend above
+               // the current mapchunk. If the mapchunk above has not generated, it
+               // will provide this required dust when it does.
                u32 vi = vm->m_area.index(x, full_node_max.Y, z);
                content_t c_full_max = vm->m_data[vi].getContent();
                s16 y_start;
@@ -819,14 +823,15 @@ void MapgenBasic::dustTopNodes()
 
                content_t c = vm->m_data[vi].getContent();
                NodeDrawType dtype = ndef->get(c).drawtype;
-               // Only place on walkable cubic non-liquid nodes
-               // Dust check needed due to vertical overgeneration
+               // Only place on cubic, walkable, non-dust nodes.
+               // Dust check needed due to avoid double layer of dust caused by
+               // dropping dust from 16 nodes above mapchunk top.
                if ((dtype == NDT_NORMAL ||
+                               dtype == NDT_ALLFACES ||
                                dtype == NDT_ALLFACES_OPTIONAL ||
-                               dtype == NDT_GLASSLIKE_FRAMED_OPTIONAL ||
                                dtype == NDT_GLASSLIKE ||
                                dtype == NDT_GLASSLIKE_FRAMED ||
-                               dtype == NDT_ALLFACES) &&
+                               dtype == NDT_GLASSLIKE_FRAMED_OPTIONAL) &&
                                ndef->get(c).walkable && c != biome->c_dust) {
                        VoxelArea::add_y(em, vi, 1);
                        vm->m_data[vi] = MapNode(biome->c_dust);