MapgenBasic node resolver: Various fixes

Add a fallback node for stair_desert_stone to avoid ignore placed
in Minimal subgame desert dungeons.
Don't allow river_water_source to fallback to water_source as river
water needs to be non-renewable and have a short flow range.
Make stair_sandstonebrick fall back to sandstonebrick instead of
sandstone.

Re-order some lines.
Add a comment.

diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index e42fc74679cf276d3054d9b65069ecae673a2349..00ae917a1006d96a1f852be8a6027555736d6abb 100644 (file)
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -587,23 +587,23 @@ MapgenBasic::MapgenBasic(int mapgenid, MapgenParams *params, EmergeManager *emer
 
        //// Look up some commonly used content
        c_stone              = ndef->getId("mapgen_stone");
-       c_water_source       = ndef->getId("mapgen_water_source");
        c_desert_stone       = ndef->getId("mapgen_desert_stone");
        c_sandstone          = ndef->getId("mapgen_sandstone");
+       c_water_source       = ndef->getId("mapgen_water_source");
        c_river_water_source = ndef->getId("mapgen_river_water_source");
 
        // Fall back to more basic content if not defined
+       // river_water_source cannot fallback to water_source because river water
+       // needs to be non-renewable and have a short flow range.
        if (c_desert_stone == CONTENT_IGNORE)
                c_desert_stone = c_stone;
        if (c_sandstone == CONTENT_IGNORE)
                c_sandstone = c_stone;
-       if (c_river_water_source == CONTENT_IGNORE)
-               c_river_water_source = c_water_source;
 
        //// Content used for dungeon generation
        c_cobble               = ndef->getId("mapgen_cobble");
-       c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
        c_mossycobble          = ndef->getId("mapgen_mossycobble");
+       c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
        c_stair_desert_stone   = ndef->getId("mapgen_stair_desert_stone");
        c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
        c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
@@ -613,10 +613,12 @@ MapgenBasic::MapgenBasic(int mapgenid, MapgenParams *params, EmergeManager *emer
                c_mossycobble = c_cobble;
        if (c_stair_cobble == CONTENT_IGNORE)
                c_stair_cobble = c_cobble;
+       if (c_stair_desert_stone == CONTENT_IGNORE)
+               c_stair_desert_stone = c_desert_stone;
        if (c_sandstonebrick == CONTENT_IGNORE)
                c_sandstonebrick = c_sandstone;
        if (c_stair_sandstonebrick == CONTENT_IGNORE)
-               c_stair_sandstonebrick = c_sandstone;
+               c_stair_sandstonebrick = c_sandstonebrick;
 }