Fixed wrong biomes list for fortresses + ranamed getConfig

1) suitable biomes for fortresses and bastions were swapped
2) renamed very generic getConfig to getStructureConfig
3) added potential way of overriding structure configs

finders.c

@@ -75,7 +75,8 @@ void setAttemptSeed(int64_t *s, int cx, int cz)
     next(s, 31);
 }
 
-int getConfig(int structureType, int mc, StructureConfig *sconf)
+
+int getStructureConfig(int structureType, int mc, StructureConfig *sconf)
 {
     switch (structureType)
     {
@@ -136,8 +137,14 @@ int getConfig(int structureType, int mc, StructureConfig *sconf)
 int getStructurePos(int structureType, int mc, int64_t seed, int regX, int regZ, Pos *pos)
 {
     StructureConfig sconf;
-    if (!getConfig(structureType, mc, &sconf))
+#if STRUCT_CONFIG_OVERRIDE
+    if (!getStructureConfig_override(structureType, mc, &sconf))
+#else
+    if (!getStructureConfig(structureType, mc, &sconf))
+#endif
+    {
         return 0;
+    }
 
     switch (structureType)
     {
@@ -170,7 +177,9 @@ int getStructurePos(int structureType, int mc, int64_t seed, int regX, int regZ,
     case Treasure:
         pos->x = (regX << 4) + 9;
         pos->z = (regZ << 4) + 9;
-        return isTreasureChunk(seed, regX, regZ);
+        seed = regX*341873128712 + regZ*132897987541 + seed + sconf.salt;
+        setSeed(&seed, seed);
+        return nextFloat(&seed) < 0.01;
 
     case Fortress:
         if (mc < MC_1_16) {
@@ -211,14 +220,6 @@ int isMineshaftChunk(int64_t seed, int chunkX, int chunkZ)
     return nextDouble(&s) < 0.004;
 }
 
-int isTreasureChunk(int64_t seed, int chunkX, int chunkZ)
-{
-    seed = chunkX*341873128712 + chunkZ*132897987541 + seed + TREASURE_CONFIG.salt;
-    setSeed(&seed, seed);
-    return nextFloat(&seed) < 0.01;
-}
-
-
 
 //==============================================================================
 // Multi-Structure Checks
@@ -1427,13 +1428,13 @@ int isViableFeatureBiome(int mc, int structureType, int biomeID)
 
     case Fortress:
         return (biomeID == nether_wastes || biomeID == soul_sand_valley ||
-                biomeID == warped_forest || biomeID == crimson_forest);
+                biomeID == warped_forest || biomeID == crimson_forest ||
+                biomeID == basalt_deltas);
 
     case Bastion:
         if (mc < MC_1_16) return 0;
         return (biomeID == nether_wastes || biomeID == soul_sand_valley ||
-                biomeID == warped_forest || biomeID == crimson_forest ||
-                biomeID == basalt_deltas);
+                biomeID == warped_forest || biomeID == crimson_forest);
 
     case End_City:
         if (mc < MC_1_9) return 0;
@@ -1788,8 +1789,10 @@ L_not_viable:
 int isViableNetherStructurePos(int structureType, int mc, NetherNoise *nn,
         int64_t seed, int blockX, int blockZ)
 {
+    if (structureType == Fortress)
+        return 1; // fortresses generate in all nether biomes and mc versions
     if (mc < MC_1_16)
-        return structureType == Fortress;
+        return 0;
 
     blockX = ((blockX >> 4) << 2) + 2;
     blockZ = ((blockZ >> 4) << 2) + 2;

finders.h

@@ -270,7 +270,17 @@ int64_t *loadSavedSeeds(const char *fnam, int64_t *scnt);
 /* Selects the structure configuration for a given version. Returns zero upon
  * failure (e.g. version does not support structure type).
  */
-int getConfig(int structureType, int mc, StructureConfig *sconf);
+int getStructureConfig(int structureType, int mc, StructureConfig *sconf);
+
+/* The library can be compiled to use a custom internal getter for structure
+ * configurations. For this, the macro STRUCT_CONFIG_OVERRIDE should be defined
+ * as true and the function getStructureConfig_override() should be defined 
+ * with a custom function body. However, note this is experimental and not all
+ * structure configs may work. (Ideally only change structure salts.)
+ */
+#if STRUCT_CONFIG_OVERRIDE
+int getStructureConfig_override(int stype, int mc, StructureConfig *sconf);
+#endif
 
 /* Finds the block position of the structure generation attempt in a given
  * region. You can use isViableStructurePos() to test if the necessary biome
@@ -310,7 +320,6 @@ Pos getLargeStructureChunkInRegion(StructureConfig config, int64_t seed, int reg
  * or at (2,2) with layer scale=4 from 1.16 onwards.
  */
 int isMineshaftChunk(int64_t seed, int chunkX, int chunkZ);
-int isTreasureChunk(int64_t seed, int chunkX, int chunkZ);
 
 // not exacly a structure
 static inline __attribute__((const))

generator.c

@@ -271,13 +271,13 @@ int genArea(const Layer *layer, int *out, int areaX, int areaZ, int areaWidth, i
 int genNetherScaled(int mc, int64_t seed, int scale, int *out,
         int x, int z, int w, int h, int y0, int y1)
 {
-    if (!scale || (scale & (scale-1)) || (scale & ~0x55))
-        return 1; // scale is not a power of 4 <= 64
+    if (scale != 1 && scale != 4 && scale != 16 && scale != 64)
+        return 1; // unsupported scale
 
     if (mc < MC_1_16)
     {
-        int siz = w*h*(y1-y0+1);
-        for (int i = 0; i < siz; i++)
+        int i, siz = w*h*(y1-y0+1);
+        for (i = 0; i < siz; i++)
             out[i] = nether_wastes;
         return 0;
     }
@@ -303,13 +303,13 @@ int genNetherScaled(int mc, int64_t seed, int scale, int *out,
         int err = mapNether2D(&nn, out, pX, pZ, pW, pH);
         if (err)
             return err;
-        Layer lvoronoi = {};
+        Layer lvoronoi = {0};
         lvoronoi.startSalt = getVoronoiSHA(seed);
         return mapVoronoi(&lvoronoi, out, x, z, w, h);
     }
     else
     {
-        return mapNether3D(&nn, out, x, z, w, h, y0, y1+1, scale, 1.0);
+        return mapNether3D(&nn, out, x, z, w, h, y0, y1-y0+1, scale, 1.0);
     }
 }
 
@@ -317,13 +317,13 @@ int genNetherScaled(int mc, int64_t seed, int scale, int *out,
 int genEndScaled(int mc, int64_t seed, int scale, int *out,
         int x, int z, int w, int h)
 {
-    if (!scale || (scale & (scale-1)) || (scale & ~0x55))
-        return 1; // scale is not a power of 4 <= 64
+    if (scale != 1 && scale != 4 && scale != 16 && scale != 64)
+        return 1; // unsupported scale
 
     if (mc < MC_1_9)
     {
-        int siz = w*h;
-        for (int i = 0; i < siz; i++)
+        int i, siz = w*h;
+        for (i = 0; i < siz; i++)
             out[i] = the_end;
         return 0;
     }
@@ -343,7 +343,7 @@ int genEndScaled(int mc, int64_t seed, int scale, int *out,
         int err = mapEnd(&en, out, pX, pZ, pW, pH);
         if (err)
             return err;
-        Layer lvoronoi = {};
+        Layer lvoronoi = {0};
         if (mc >= MC_1_15)
         {
             lvoronoi.startSalt = getVoronoiSHA(seed);