Fix 1.18 spawn and stronghold finders (please fix MC-241546, Mojang)

README.md

@@ -277,7 +277,7 @@ Strongholds as well as the world spawn point actually search until they find a s
 
 int main()
 {
-    int mc = MC_1_17;
+    int mc = MC_1_18;
     uint64_t seed = 3055141959546LL;
 
     // Only the first stronghold has a position which can be estimated

finders.c

@@ -944,12 +944,17 @@ Pos locateBiome(
         x >>= 2;
         z >>= 2;
         radius >>= 2;
+        uint64_t dat = 0;
 
-        for (i = -radius; i <= radius; i++)
+        for (j = -radius; j <= radius; j++)
         {
-            for (j = -radius; j <= radius; j++)
+            for (i = -radius; i <= radius; i++)
             {
-                int id = getBiomeAt(g, 4, x+i, y, z+j);
+                int id, xi = x+i, zj = z+j;
+                // emulate dependent biome generation MC-241546
+                //id = getBiomeAt(g, 4, xi, y, zj);
+                id = sampleBiomeNoise(&g->bn, NULL, xi, y, zj, &dat, 0);
+
                 if (!validBiomes[id]) continue;
                 if (found == 0 || nextInt(rng, found+1) == 0)
                 {
@@ -1114,28 +1119,29 @@ const char* getValidStrongholdBiomes(int mc)
         modified_gravelly_mountains, shattered_savanna,
         shattered_savanna_plateau, eroded_badlands,
         modified_wooded_badlands_plateau, modified_badlands_plateau,
-        bamboo_jungle, bamboo_jungle_hills,
+        bamboo_jungle, bamboo_jungle_hills, dripstone_caves, lush_caves, meadow,
+        grove, snowy_slopes, stony_peaks, jagged_peaks, frozen_peaks,
     };
-
-    static char isValid115[256], isValid[256];
     unsigned int i;
+    static char v15[256], v17[256], v18[256];
+    char *valid = (mc <= MC_1_15 ? v15 : mc <= MC_1_17 ? v17 : v18);
 
-    if (mc <= MC_1_15)
+    if (!valid[strongholdBiomes[0]])
     {
-        if (!isValid115[strongholdBiomes[0]])
+        for (i = 0; i < sizeof(strongholdBiomes)/sizeof(int); i++)
-            for (i = 0; i < sizeof(strongholdBiomes) / sizeof(int); i++)
+            valid[ strongholdBiomes[i] ] = 1;
-                isValid115[ strongholdBiomes[i] ] = 1;
+
-        return isValid115;
+        if (mc >= MC_1_18)
-    }
+        {
-    else
+            valid[stone_shore] = 0;
-    {   // simulate MC-199298
+        }
-        if (!isValid[strongholdBiomes[0]])
+        else if (mc >= MC_1_16)
-            for (i = 0; i < sizeof(strongholdBiomes) / sizeof(int); i++)
+        {   // simulate MC-199298
-                isValid[ strongholdBiomes[i] ] = 1;
+            valid[bamboo_jungle] = 0;
-        isValid[bamboo_jungle] = 0;
+            valid[bamboo_jungle_hills] = 0;
-        isValid[bamboo_jungle_hills] = 0;
+        }
-        return isValid;
     }
+    return valid;
 }
 
 Pos initFirstStronghold(StrongholdIter *sh, int mc, uint64_t s48)
@@ -1343,6 +1349,79 @@ static int findServerSpawn(const Generator *g, int chunkX, int chunkZ,
     }
 }
 
+static
+uint64_t getSpawnDist(const Generator *g, int x, int z)
+{
+    int64_t np[6];
+    uint32_t flags = SAMPLE_NO_DEPTH | SAMPLE_NO_BIOME;
+    sampleBiomeNoise(&g->bn, np, x>>2, 0, z>>2, NULL, flags);
+    const int64_t spawn_np[][2] = {
+        {-10000,10000},{-10000,10000},{-1100,10000},{-10000,10000},{0,0},
+        {-10000,-1600},{1600,10000} // [6]: weirdness for the second noise point
+    };
+    uint64_t ds = 0, ds1 = 0, ds2 = 0;
+    uint64_t a, b, q, i;
+    for (i = 0; i < 5; i++)
+    {
+        a = +np[i] - (uint64_t)spawn_np[i][1];
+        b = -np[i] + (uint64_t)spawn_np[i][0];
+        q = (int64_t)a > 0 ? a : (int64_t)b > 0 ? b : 0;
+        ds += q * q;
+    }
+    a = +np[5] - (uint64_t)spawn_np[5][1];
+    b = -np[5] + (uint64_t)spawn_np[5][0];
+    q = (int64_t)a > 0 ? a : (int64_t)b > 0 ? b : 0;
+    ds1 = ds + q*q;
+    a = +np[5] - (uint64_t)spawn_np[6][1];
+    b = -np[5] + (uint64_t)spawn_np[6][0];
+    q = (int64_t)a > 0 ? a : (int64_t)b > 0 ? b : 0;
+    ds2 = ds + q*q;
+    return ds1 <= ds2 ? ds1 : ds2;
+}
+
+static
+void findFittest(const Generator *g, Pos *pos, uint64_t *fitness, double maxrad, double step)
+{
+    double rad = step, ang = 0;
+    Pos p = *pos;
+    while (rad <= maxrad)
+    {
+        int x = p.x + (int)(sin(ang) * rad);
+        int z = p.z + (int)(cos(ang) * rad);
+        // calc fitness
+        double d = ((double)x*x + (double)z*z) / (2500*2500);
+        uint64_t fit = (uint64_t)(d*d * 1e8);
+        // calculate the distance to the noise points for spawn
+        fit += getSpawnDist(g, x, z);
+        if (fit < *fitness)
+        {
+            pos->x = x;
+            pos->z = z;
+            *fitness = fit;
+        }
+
+        ang += step / rad;
+        if (ang <= M_PI*2)
+            continue;
+        ang = 0;
+        rad += step;
+    }
+}
+
+static
+Pos findFittestPos(const Generator *g)
+{
+    Pos spawn = {0, 0};
+    uint64_t fitness = getSpawnDist(g, 0, 0);
+    findFittest(g, &spawn, &fitness, 2048.0, 512.0);
+    findFittest(g, &spawn, &fitness, 512.0, 32.0);
+    // center of chunk
+    spawn.x = ((spawn.x >> 4) << 4) + 8;
+    spawn.z = ((spawn.z >> 4) << 4) + 8;
+    return spawn;
+}
+
+
 Pos getSpawn(const Generator *g)
 {
     const char *isSpawnBiome = getValidSpawnBiomes();
@@ -1351,13 +1430,18 @@ Pos getSpawn(const Generator *g)
     int i;
 
     uint64_t rnd;
-    setSeed(&rnd, g->seed);
+    if (g->mc <= MC_1_17)
-    spawn = locateBiome(g, 0, 63, 0, 256, isSpawnBiome, &rnd, &found);
-
-    if (!found)
     {
-        //printf("Unable to find spawn biome.\n");
+        setSeed(&rnd, g->seed);
-        spawn.x = spawn.z = 8;
+        spawn = locateBiome(g, 0, 63, 0, 256, isSpawnBiome, &rnd, &found);
+        if (!found)
+        {
+            spawn.x = spawn.z = 8;
+        }
+    }
+    else
+    {
+        spawn = findFittestPos(g);
     }
 
     double accum = 1;
@@ -1374,7 +1458,7 @@ Pos getSpawn(const Generator *g)
         {
             if (j > -16 && j <= 16 && k > -16 && k <= 16)
             {
-                if (findServerSpawn(g, (spawn.x>>4)+j, (spawn.x>>4)+k,
+                if (findServerSpawn(g, (spawn.x>>4)+j, (spawn.z>>4)+k,
                     &bx, &bz, &bn, &accum))
                 {
                     spawn.x = (int) round(bx / bn);
@@ -1420,25 +1504,30 @@ Pos getSpawn(const Generator *g)
     return spawn;
 }
 
-
 Pos estimateSpawn(const Generator *g)
 {
     const char *isSpawnBiome = getValidSpawnBiomes();
     Pos spawn;
-    int found;
-    uint64_t rnd;
-    setSeed(&rnd, g->seed);
-    spawn = locateBiome(g, 0, 63, 0, 256, isSpawnBiome, &rnd, &found);
 
-    if (!found)
+    if (g->mc <= MC_1_17)
     {
-        spawn.x = spawn.z = 8;
+        int found;
+        uint64_t rnd;
+        setSeed(&rnd, g->seed);
+        spawn = locateBiome(g, 0, 63, 0, 256, isSpawnBiome, &rnd, &found);
+        if (!found)
+        {
+            spawn.x = spawn.z = 8;
+        }
+        if (g->mc >= MC_1_13)
+        {
+            spawn.x &= ~0xf;
+            spawn.z &= ~0xf;
+        }
     }
-
+    else
-    if (g->mc >= MC_1_13)
     {
-        spawn.x &= ~0xf;
+        spawn = findFittestPos(g);
-        spawn.z &= ~0xf;
     }
 
     return spawn;

layers.c

@@ -1354,11 +1354,12 @@ int p2overworld(const uint64_t np[6], uint64_t *dat);
 #endif
 
 /// Biome sampler for MC 1.18
-int sampleBiomeNoise(const BiomeNoise *bn, int x, int y, int z, uint64_t *dat, int approx)
+int sampleBiomeNoise(const BiomeNoise *bn, int64_t *np, int x, int y, int z,
+    uint64_t *dat, uint32_t flags)
 {
     float t = 0, h = 0, c = 0, e = 0, d = 0, w = 0;
     double px = x, pz = z;
-    if (approx == 0)
+    if (!(flags & SAMPLE_NO_SHIFT))
     {
         px += sampleDoublePerlin(&bn->shift, x, 0, z) * 4.0;
         pz += sampleDoublePerlin(&bn->shift, z, x, 0) * 4.0;
@@ -1368,27 +1369,32 @@ int sampleBiomeNoise(const BiomeNoise *bn, int x, int y, int z, uint64_t *dat, i
     e = sampleDoublePerlin(&bn->erosion, px, 0, pz);
     w = sampleDoublePerlin(&bn->weirdness, px, 0, pz);
 
-    float np_param[] = {
+    if (!(flags & SAMPLE_NO_DEPTH))
-        c, e, -3.0F * ( fabsf( fabsf(w) - 0.6666667F ) - 0.33333334F ), w,
+    {
-    };
+        float np_param[] = {
-    double off = getSpline(bn->sp, np_param) + 0.015F;
+            c, e, -3.0F * ( fabsf( fabsf(w) - 0.6666667F ) - 0.33333334F ), w,
+        };
+        double off = getSpline(bn->sp, np_param) + 0.015F;
 
-    //double py = y + sampleDoublePerlin(&bn->shift, y, z, x) * 4.0;
+        //double py = y + sampleDoublePerlin(&bn->shift, y, z, x) * 4.0;
-    d = 1.0 - (y << 2) / 128.0 - 83.0/160.0 + off;
+        d = 1.0 - (y << 2) / 128.0 - 83.0/160.0 + off;
+    }
 
     t = sampleDoublePerlin(&bn->temperature, px, 0, pz);
     h = sampleDoublePerlin(&bn->humidity, px, 0, pz);
 
-    int64_t np[] = {
+    int64_t l_np[6];
-        (int64_t)(10000.0F*t),
+    int64_t *p_np = np ? np : l_np;
-        (int64_t)(10000.0F*h),
+    p_np[0] = (int64_t)(10000.0F*t);
-        (int64_t)(10000.0F*c),
+    p_np[1] = (int64_t)(10000.0F*h);
-        (int64_t)(10000.0F*e),
+    p_np[2] = (int64_t)(10000.0F*c);
-        (int64_t)(10000.0F*d),
+    p_np[3] = (int64_t)(10000.0F*e);
-        (int64_t)(10000.0F*w),
+    p_np[4] = (int64_t)(10000.0F*d);
-    };
+    p_np[5] = (int64_t)(10000.0F*w);
 
-    int id = p2overworld((const uint64_t*)np, dat);
+    int id = none;
+    if (!(flags & SAMPLE_NO_BIOME))
+        id = p2overworld((const uint64_t*)p_np, dat);
     return id;
 }
 
@@ -1396,6 +1402,8 @@ int sampleBiomeNoise(const BiomeNoise *bn, int x, int y, int z, uint64_t *dat, i
 static void genBiomeNoise3D(const BiomeNoise *bn, int *out, Range r, int opt)
 {
     uint64_t dat = 0;
+    uint64_t *p_dat = opt ? &dat : NULL;
+    uint32_t flags = opt ? SAMPLE_NO_SHIFT : 0;
     int i, j, k;
     int *p = out;
     int scale = r.scale > 4 ? r.scale / 4 : 1;
@@ -1409,7 +1417,7 @@ static void genBiomeNoise3D(const BiomeNoise *bn, int *out, Range r, int opt)
             for (i = 0; i < r.sx; i++)
             {
                 int xi = (r.x+i)*scale + mid;
-                *p = sampleBiomeNoise(bn, xi, yk, zj, opt ? &dat : NULL, opt);
+                *p = sampleBiomeNoise(bn, NULL, xi, yk, zj, p_dat, flags);
                 p++;
             }
         }
@@ -1457,7 +1465,7 @@ int genBiomeNoiseScaled(const BiomeNoise *bn, int *out, Range r, int mc, uint64_
                     }
                     else
                     {
-                        *p = sampleBiomeNoise(bn, x4, y4, z4, 0, 0);
+                        *p = sampleBiomeNoise(bn, 0, x4, y4, z4, 0, 0);
                     }
                     p++;
                 }

layers.h

@@ -436,9 +436,15 @@ int genEndScaled(const EndNoise *en, int *out, Range r, int mc, uint64_t sha);
  * The 1.18 End generation remains similar to 1.17 and does NOT use the
  * biome noise.
  */
+enum {
+    SAMPLE_NO_SHIFT = 0x1,
+    SAMPLE_NO_DEPTH = 0x2,
+    SAMPLE_NO_BIOME = 0x4,
+};
 void initBiomeNoise(BiomeNoise *bn, int mc);
 void setBiomeSeed(BiomeNoise *bn, uint64_t seed, int large);
-int sampleBiomeNoise(const BiomeNoise *bn, int x, int y, int z, uint64_t *dat, int approx);
+int sampleBiomeNoise(const BiomeNoise *bn, int64_t *np, int x, int y, int z,
+    uint64_t *dat, uint32_t flags);
 /**
  * The scaled biome noise generation applies for the Overworld version 1.18.
  * The 'sha' hash of the seed is only required for voronoi at scale 1:1.

tests.c

@@ -112,7 +112,7 @@ int testBiomeGen1x1(const int *mc, const uint32_t *expect, int dim, int bits, in
         fflush(stdout);
 
         double t = -now();
-        h = getRef(mc[test], dim, bits, spread, "t16");
+        h = getRef(mc[test], dim, bits, spread, NULL);
         t += now();
         printf("got %08x %s\e[0m (%ld msec)\n",
             h, h == expect[test] ? "\e[1;92mOK" : "\e[1;91mFAILED",
@@ -158,6 +158,8 @@ uint32_t testAreas(int mc, int dim, int scale)
 }
 
 
+
+
 int testGeneration()
 {
     const int mc_vers[] = {
@@ -172,9 +174,20 @@ int testGeneration()
     };
     const int testcnt = sizeof(mc_vers) / sizeof(int);
 
-    printf("Testing 1x1 biome generation (quick):\n");
+    //printf("Testing 1x1 biome generation (quick):\n");
-    if (!testBiomeGen1x1(mc_vers, b6_hashes, 0, 6, 1, 1))// testcnt))
+    //if (!testBiomeGen1x1(mc_vers, b6_hashes, 0, 6, 1, testcnt))
-        ;//return -1;
+    //    return -1;
+
+    Generator g;
+    setupGenerator(&g, MC_1_18, 0);
+    applySeed(&g, 0, 1234);
+    Pos p = getSpawn(&g);
+    printf("%d %d\n", p.x, p.z);
+
+    StrongholdIter sh;
+    initFirstStronghold(&sh, g.mc, g.seed);
+    while (nextStronghold(&sh, &g) > 0)
+        printf("Stronghold #: (%6d, %6d)\n", sh.pos.x, sh.pos.z);
 
     printf("Area generation tests:\n");
     testAreas(MC_1_18, 0, 1);