Adds a new procedural generation algorithm that will be used to generate a more cave-system like Lavaland

Cargo.toml

@@ -92,6 +92,7 @@ zeroize = { version = "1.8", optional = true }
 default = [
     "acreplace",
     "batchnoise",
+    "cave_system_generator",
     "cellularnoise",
     "dmi",
     "file",
@@ -116,6 +117,7 @@ default = [
 all = [
     "acreplace",
     "batchnoise",
+    "cave_system_generator",
     "cellularnoise",
     "dmi",
     "dice",
@@ -147,6 +149,7 @@ all = [
 # default features
 acreplace = ["aho-corasick"]
 batchnoise = ["dbpnoise"]
+cave_system_generator = ["rand", "rayon", "serde", "serde_json"]
 cellularnoise = ["rand", "rayon"]
 dmi = ["png", "image", "qrcode", "serde_repr"]
 file = []

dmsrc/cave-system-generator.dm

@@ -0,0 +1,25 @@
+/**
+ * Generates a procedural dungeon map using BSP tree partitioning, prefab placement,
+ * MST corridor generation, and Cellular Automata smoothing.
+ *
+ * Returns a plain binary grid string (matching cellularnoise format):
+ * A width*height string of '0' (wall) and '1' (floor) characters in row-major order.
+ *
+ * Arguments:
+ * * width - Grid width
+ * * height - Grid height
+ * * prefabs_json - JSON array of prefab configs: [{"x":55,"y":65,"w":10,"h":10,"isEnclosed":true},...] (if none use "[]") x = bottom-left turf x, y = bottom-left turf y, w = prefab width, h = prefab height, isEnclosed = whether prefab should be treated like its wall or floor by the generation
+ * * min_bsp_size - Minimum BSP leaf dimension
+ * * max_ratio - Maximum aspect ratio for BSP splits
+ * * padding - Room edge padding within BSP leaf
+ * * room_fill_percent - How much of each BSP leaf a room fills, 1-100
+ * * corridor_width - Width of corridors between rooms
+ * * loop_percent - Chance to add extra MST edges for loops
+ * * noise_percent - Initial random floor density
+ * * ca_steps - Cellular Automata smoothing iterations
+ * * birth_limit - Neighbors to create floor (>=)
+ * * survival_limit - Neighbors to survive as floor (>=)
+ * * edge_is_alive - Whether out-of-bounds cells count as ALIVE (floor) for CA neighbor counts
+ */
+#define rustg_cave_system_generator_generate(width, height, prefabs_json, min_bsp_size, max_ratio, padding, room_fill_percent, corridor_width, loop_percent, noise_percent, ca_steps, birth_limit, survival_limit, edge_is_alive) \
+	RUSTG_CALL(RUST_G, "cave_system_generator_generate")(width, height, prefabs_json, min_bsp_size, max_ratio, padding, room_fill_percent, corridor_width, loop_percent, noise_percent, ca_steps, birth_limit, survival_limit, edge_is_alive)