Implement rltiles %weight command and skewed dngn tile probabilities.

In dc-dngn.txt you can now use the %weight command to specify the
probability of a given tile whenever a variant is chosen randomly
from a set of variant tiles.

Example:
%weight 5
floor/floor_sand_stone0 FLOOR_SAND_STONE
floor/floor_sand_stone1
floor/floor_sand_stone2
floor/floor_sand_stone3
%weight 2
floor/floor_sand_stone4
floor/floor_sand_stone5
floor/floor_sand_stone7
%weight 1
floor/floor_sand_stone6

... will make plain sand more likely than the rocky versions and the
big rock rarer than the smaller ones.

This is not visible from the dngn.png but you can check the (cumulative)
weights in tiledef-dngn.cc.

Aside from the above, this is also used for the brick wall in all its
colorations. (The repeat command also repeats the weight settings.)

1 files changed, 22 insertions, 4 deletions

diff --git a/crawl-ref/source/tilepick.cc b/crawl-ref/source/tilepick.cc
index d56139759a..999a8d38ca 100644
--- a/crawl-ref/source/tilepick.cc
+++ b/crawl-ref/source/tilepick.cc
@@ -4510,6 +4510,26 @@ void tile_init_flavour()
         tile_init_flavour(*ri);
 }
 
+static int _pick_random_dngn_tile(unsigned int idx)
+{
+    ASSERT(idx >= 0 && idx < TILE_DNGN_MAX);
+    const int count = tile_dngn_count(idx);
+    if (count == 1)
+        return (idx);
+
+    const int total = tile_dngn_probs(idx + count - 1);
+    const int rand  = random2(total);
+
+    for (int i = 0; i < count; ++i)
+    {
+        int curr = idx + i;
+        if (rand < tile_dngn_probs(curr))
+            return (curr);
+    }
+
+    return (idx);
+}
+
 void tile_init_flavour(const coord_def &gc)
 {
     if (!map_bounds(gc))
@@ -4521,8 +4541,7 @@ void tile_init_flavour(const coord_def &gc)
         int colour = env.grid_colours(gc);
         if (colour)
             floor_base = tile_dngn_coloured(floor_base, colour);
-        int floor_rnd = random2(tile_dngn_count(floor_base));
-        env.tile_flv(gc).floor = floor_base + floor_rnd;
+        env.tile_flv(gc).floor = _pick_random_dngn_tile(floor_base);
     }
 
     if (!env.tile_flv(gc).wall)
@@ -4531,8 +4550,7 @@ void tile_init_flavour(const coord_def &gc)
         int colour = env.grid_colours(gc);
         if (colour)
             wall_base = tile_dngn_coloured(wall_base, colour);
-        int wall_rnd = random2(tile_dngn_count(wall_base));
-        env.tile_flv(gc).wall = wall_base + wall_rnd;
+        env.tile_flv(gc).wall = _pick_random_dngn_tile(wall_base);
     }
 
     if (feat_is_door(grd(gc)))