Mgvalleys: Don't let cavegen place biome nodes everywhere

Fix use of 'air_above' bool so that biome
nodes are only placed in tunnel floors
Minor code improvements
'Continue' when massive cave air is placed

diff --git a/src/mapgen_valleys.cpp b/src/mapgen_valleys.cpp
index be122aacec553fae5575981f9552f2c4e89ff062..3926deb4ab15412c822af65e4f9da44713c44400 100644 (file)
--- a/src/mapgen_valleys.cpp
+++ b/src/mapgen_valleys.cpp
@@ -921,14 +921,13 @@ void MapgenValleys::generateCaves(s16 max_stone_y)
        }
 
        u32 index_2d = 0;
-       u32 index_3d = 0;
        for (s16 z = node_min.Z; z <= node_max.Z; z++)
        for (s16 x = node_min.X; x <= node_max.X; x++, index_2d++) {
                Biome *biome = (Biome *)bmgr->getRaw(biomemap[index_2d]);
-               bool air_above = false;
+               bool tunnel_air_above = false;
                bool underground = false;
                u32 index_data = vm->m_area.index(x, node_max.Y, z);
-               index_3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride + (x - node_min.X);
+               u32 index_3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride + (x - node_min.X);
 
                // Dig caves on down loop to check for air above.
                // Don't excavate the overgenerated stone at node_max.Y + 1,
@@ -942,12 +941,10 @@ void MapgenValleys::generateCaves(s16 max_stone_y)
                        float terrain = noise_terrain_height->result[index_2d];
 
                        // Saves some time.
-                       if (y > terrain + 10) {
-                               air_above = true;
+                       if (y > terrain + 10)
                                continue;
-                       } else if (y < terrain - 40) {
+                       else if (y < terrain - 40)
                                underground = true;
-                       }
 
                        // Dig massive caves.
                        if (node_max.Y <= massive_cave_depth
@@ -955,6 +952,7 @@ void MapgenValleys::generateCaves(s16 max_stone_y)
                                        > tcave_cache[y - node_min.Y + 1]) {
                                vm->m_data[index_data] = n_air;
                                made_a_big_one = true;
+                               continue;
                        }
 
                        content_t c = vm->m_data[index_data].getContent();
@@ -963,54 +961,51 @@ void MapgenValleys::generateCaves(s16 max_stone_y)
 
                        // River water is not set as ground content
                        // in the default game. This can produce strange results
-                       // when a cave undercuts a river. However, that's not for
+                       // when a tunnel undercuts a river. However, that's not for
                        // the mapgen to correct. Fix it in lua.
 
-                       if (c == CONTENT_AIR) {
-                               air_above = true;
-                       } else if (d1 * d2 > 0.3f && ndef->get(c).is_ground_content) {
-                               // in a cave
+                       if (d1 * d2 > 0.3f && ndef->get(c).is_ground_content) {
+                               // in a tunnel
                                vm->m_data[index_data] = n_air;
-                               air_above = true;
-                       } else if (air_above && (c == biome->c_filler || c == biome->c_stone)) {
-                               // at the cave floor
-                               s16 sr = ps.range(0,39);
-                               u32 j = index_data;
-                               vm->m_area.add_y(em, j, 1);
-
-                               if (sr > terrain - y) {
-                                       // Put dirt in caves near the surface.
-                                       if (underground)
-                                               vm->m_data[index_data] = MapNode(biome->c_filler);
-                                       else
-                                               vm->m_data[index_data] = MapNode(biome->c_top);
-                               } else if (sr < 3 && underground) {
-                                       sr = abs(ps.next());
-                                       if (lava_features_lim > 0 && y <= lava_max_height
-                                                       && c == biome->c_stone && sr < lava_chance)
-                                               vm->m_data[j] = n_lava;
-
-                                       sr -= lava_chance;
-
-                                       // If sr < 0 then we should have already placed lava --
-                                       // don't immediately dump water on it.
-                                       if (water_features_lim > 0 && y <= cave_water_max_height
-                                                       && sr >= 0 && sr < water_chance)
-                                               vm->m_data[j] = n_water;
+                               tunnel_air_above = true;
+                       } else if (c == biome->c_filler || c == biome->c_stone) {
+                               if (tunnel_air_above) {
+                                       // at the tunnel floor
+                                       s16 sr = ps.range(0, 39);
+                                       u32 j = index_data;
+                                       vm->m_area.add_y(em, j, 1);
+
+                                       if (sr > terrain - y) {
+                                               // Put dirt in tunnels near the surface.
+                                               if (underground)
+                                                       vm->m_data[index_data] = MapNode(biome->c_filler);
+                                               else
+                                                       vm->m_data[index_data] = MapNode(biome->c_top);
+                                       } else if (sr < 3 && underground) {
+                                               sr = abs(ps.next());
+                                               if (lava_features_lim > 0 && y <= lava_max_height
+                                                               && c == biome->c_stone && sr < lava_chance)
+                                                       vm->m_data[j] = n_lava;
+
+                                               sr -= lava_chance;
+
+                                               // If sr < 0 then we should have already placed lava --
+                                               // don't immediately dump water on it.
+                                               if (water_features_lim > 0 && y <= cave_water_max_height
+                                                               && sr >= 0 && sr < water_chance)
+                                                       vm->m_data[j] = n_water;
+                                       }
                                }
 
-                               air_above = false;
-                               underground = true;
-                       } else if (c == biome->c_filler || c == biome->c_stone) {
-                               air_above = false;
+                               tunnel_air_above = false;
                                underground = true;
                        } else {
-                               air_above = false;
+                               tunnel_air_above = false;
                        }
                }
        }
 
-       if (node_max.Y <= large_cave_depth && (!made_a_big_one)) {
+       if (node_max.Y <= large_cave_depth && !made_a_big_one) {
                u32 bruises_count = ps.range(0, 2);
                for (u32 i = 0; i < bruises_count; i++) {
                        CaveV5 cave(this, &ps);