better map generation

src/map.ml

@@ -55,16 +55,6 @@ type t =
   ; height : int
   }
 
-let init () =
-  let width = 100 in
-  let height = 90 in
-  let tiles =
-    Array.init width (fun _x ->
-        Array.init height (fun _y ->
-            if Random.int 1000 <= 42 then Water else Grass ) )
-  in
-  { tiles; width; height }
-
 let get_tile_kind ~x ~y map =
   try map.tiles.(x).(y) with Invalid_argument _ -> Black
 
@@ -93,3 +83,75 @@ let check_move map ({ x; y; _ } as pos) movement_dir =
   | (Black | Water) as bg ->
     Error (Format.asprintf "can't move on %a" pp_background bg)
   | Grass | Wheat -> Ok { pos with x; y }
+
+let n = 50
+
+let m = 50
+
+let nb_water_spread = 4
+
+let p_water_spread = 0.5
+
+let p_water_init = 0.005
+
+let nb_tree_spread = 6
+
+let p_tree_spread = 0.5
+
+let p_tree_init = 0.01
+
+let () = Random.self_init ()
+
+let count_something t map =
+  let is_something t e = if e = t then 1 else 0 in
+  let f = is_something t in
+  Array.init n (fun i ->
+      Array.init m (fun j ->
+          if i = 0 || j = 0 || i = n - 1 || j = m - 1 then 0
+          else
+            f map.(i - 1).(j)
+            + f map.(i + 1).(j)
+            + f map.(i).(j + 1)
+            + f map.(i).(j - 1) ) )
+
+let populate t map i p_init p_spread =
+  let map =
+    Array.map
+      (fun ligne ->
+        Array.map
+          (fun e ->
+            let random = Random.float 1.0 in
+            if e = Grass && random < p_init then t else e )
+          ligne )
+      map
+  in
+
+  let rec loop acc i =
+    if i = 0 then acc
+    else
+      let tbl_count = count_something t acc in
+      let acc =
+        Array.mapi
+          (fun i ligne ->
+            Array.mapi
+              (fun j e ->
+                let random = Random.float 1.0 in
+                if
+                  e = Grass
+                  && random < p_spread *. Float.of_int tbl_count.(i).(j)
+                then t
+                else e )
+              ligne )
+          acc
+      in
+      loop acc (i - 1)
+  in
+  loop map i
+
+let init () =
+  let tiles = Array.init n (fun _i -> Array.init m (fun _j -> Grass)) in
+  let tiles =
+    populate Water tiles nb_water_spread p_water_init p_water_spread
+  in
+  (*let tiles = populate Tree map nb_tree_spread p_tree_init p_tree_spread in*)
+  { tiles; width = n; height = m }