Mgv7: Avoid mid-air spawn on disabled mountain terrain, optimise function

'getSpawnLevelAtPoint()' did not account for disabled mountains, it
was possible to be spawned in mid-air where a mountain surface would
have been.

Avoid check for river area if rivers are disabled.

diff --git a/src/mapgen_v7.cpp b/src/mapgen_v7.cpp
index d14fdb97a5f0ea56eac2d83164ec2d06147f8b9f..86f559af3ec9fc67de20a34b85e54107f475ee56 100644 (file)
--- a/src/mapgen_v7.cpp
+++ b/src/mapgen_v7.cpp
@@ -154,17 +154,27 @@ int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
        // Base terrain calculation
        s16 y = baseTerrainLevelAtPoint(p.X, p.Y);
 
-       // Ridge/river terrain calculation
-       float width = 0.2;
-       float uwatern = NoisePerlin2D(&noise_ridge_uwater->np, p.X, p.Y, seed) * 2;
-       // if inside a river this is an unsuitable spawn point
-       if (fabs(uwatern) <= width)
-               return MAX_MAP_GENERATION_LIMIT;
+       // If enabled, check if inside a river
+       if (spflags & MGV7_RIDGES) {
+               float width = 0.2;
+               float uwatern = NoisePerlin2D(&noise_ridge_uwater->np, p.X, p.Y, seed) * 2;
+               if (fabs(uwatern) <= width)
+                       return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
+       }
+
+       // If mountains are disabled, terrain level is base terrain level
+       // Avoids spawn on non-existant mountain terrain
+       if (!(spflags & MGV7_MOUNTAINS)) {
+               if (y <= water_level || y > water_level + 16)
+                       return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
+               else
+                       return y;
+       }
 
        // Mountain terrain calculation
        int iters = 128;
        while (iters--) {
-               if (!getMountainTerrainAtPoint(p.X, y + 1, p.Y)) {  // Air, y is ground level
+               if (!getMountainTerrainAtPoint(p.X, y + 1, p.Y)) {  // If air above
                        if (y <= water_level || y > water_level + 16)
                                return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
                        else
@@ -173,7 +183,7 @@ int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
                y++;
        }
 
-       // Unsuitable spawn point, no ground surface found
+       // Unsuitable spawn point, no mountain surface found
        return MAX_MAP_GENERATION_LIMIT;
 }