build ore addon

common/api/src/main/java/com/dfsek/terra/api/util/MaterialSet.java

@@ -0,0 +1,8 @@
+package com.dfsek.terra.api.util;
+
+import com.dfsek.terra.api.block.BlockType;
+
+import java.util.Set;
+
+public interface MaterialSet extends Set<BlockType> {
+}

common/api/src/main/java/com/dfsek/terra/api/util/PopulationUtil.java

@@ -0,0 +1,28 @@
+package com.dfsek.terra.api.util;
+
+import com.dfsek.terra.api.world.Chunk;
+
+import java.util.Random;
+
+public final class PopulationUtil {
+    public static Random getRandom(Chunk c) {
+        return getRandom(c, 0);
+    }
+
+    public static Random getRandom(Chunk c, long salt) {
+        return new Random(getCarverChunkSeed(c.getX(), c.getZ(), c.getWorld().getSeed() + salt));
+    }
+
+    /**
+     * Gets the carver seed for a chunk.
+     *
+     * @param chunkX Chunk's X coordinate
+     * @param chunkZ Chunk's Z coordinate
+     * @param seed   World seed
+     * @return long - The carver seed.
+     */
+    public static long getCarverChunkSeed(int chunkX, int chunkZ, long seed) {
+        Random r = new Random(seed);
+        return chunkX * r.nextLong() ^ chunkZ * r.nextLong() ^ seed;
+    }
+}