Fix Mapgen Valleys getSpawnLevelAtPoint() (#7756)

diff --git a/src/mapgen/mapgen_valleys.cpp b/src/mapgen/mapgen_valleys.cpp
index 404ec585a8c193f5b06f844342156d95c9ca53a4..5f9267875f8ad65e159fd9dd44ab3374439f3f08 100644 (file)
--- a/src/mapgen/mapgen_valleys.cpp
+++ b/src/mapgen/mapgen_valleys.cpp
@@ -393,18 +393,27 @@ float MapgenValleys::terrainLevelFromNoise(TerrainNoise *tn)
 float MapgenValleys::adjustedTerrainLevelFromNoise(TerrainNoise *tn)
 {
        float mount = terrainLevelFromNoise(tn);
+       float result = mount;
        s16 y_start = myround(mount);
-
-       for (s16 y = y_start; y <= y_start + 1000; y++) {
-               float fill =
+       float fill =
+               NoisePerlin3D(&noise_inter_valley_fill->np, tn->x, y_start, tn->z, seed);
+       bool is_ground = fill * *tn->slope >= y_start - mount;
+       s16 search_direction = is_ground ? 1 : -1;
+
+       for (s16 i = 1; i <= 1000; i++) {
+               s16 y = y_start + i * search_direction;
+               fill =
                        NoisePerlin3D(&noise_inter_valley_fill->np, tn->x, y, tn->z, seed);
-               if (fill * *tn->slope < y - mount) {
-                       mount = std::fmax((float)(y - 1), mount);
+
+               bool was_ground = is_ground;
+               is_ground = fill * *tn->slope >= y - mount;
+               if (is_ground)
+                       result = y;
+               if (is_ground != was_ground)
                        break;
-               }
        }
 
-       return mount;
+       return result;
 }
 
 
@@ -420,7 +429,8 @@ int MapgenValleys::getSpawnLevelAtPoint(v2s16 p)
                        level_at_point > water_level + 16)
                return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
 
-       return level_at_point;
+       // +1 to account for biome dust that can be 1 node deep
+       return level_at_point + 1; 
 }