Save old colour in terrain-change markers (#8806)

It is still possible to lose the colour if the cell is permanently
reverted to its original type: for example, using Tomb on coloured
floor then digging out.

5 files changed, 32 insertions, 11 deletions

diff --git a/crawl-ref/source/mapmark.cc b/crawl-ref/source/mapmark.cc
index aec021857b..892b9744a2 100644
--- a/crawl-ref/source/mapmark.cc
+++ b/crawl-ref/source/mapmark.cc
@@ -776,9 +776,10 @@ string map_door_seal_marker::debug_describe() const
 
 map_terrain_change_marker::map_terrain_change_marker (const coord_def& p,
                     dungeon_feature_type oldfeat, dungeon_feature_type newfeat,
-                    int dur, terrain_change_type ctype, int mnum)
+                    int dur, terrain_change_type ctype, int mnum, int oldcol)
     : map_marker(MAT_TERRAIN_CHANGE, p), duration(dur), mon_num(mnum),
-        old_feature(oldfeat), new_feature(newfeat), change_type(ctype)
+      old_feature(oldfeat), new_feature(newfeat), change_type(ctype),
+      colour(oldcol)
 {
 }
 
@@ -790,6 +791,7 @@ void map_terrain_change_marker::write(writer &out) const
     marshallUByte(out, new_feature);
     marshallUByte(out, change_type);
     marshallShort(out, mon_num);
+    marshallUByte(out, colour);
 }
 
 void map_terrain_change_marker::read(reader &in)
@@ -801,6 +803,12 @@ void map_terrain_change_marker::read(reader &in)
     new_feature = static_cast<dungeon_feature_type>(unmarshallUByte(in));
     change_type = static_cast<terrain_change_type>(unmarshallUByte(in));
     mon_num = unmarshallShort(in);
+#if TAG_MAJOR_VERSION == 34
+    if (in.getMinorVersion() < TAG_MINOR_SAVE_TERRAIN_COLOUR)
+        colour = BLACK;
+    else
+#endif
+        colour = unmarshallUByte(in);
 }
 
 map_marker *map_terrain_change_marker::read(reader &in, map_marker_type)
@@ -814,7 +822,7 @@ map_marker *map_terrain_change_marker::clone() const
 {
     map_terrain_change_marker *mark =
         new map_terrain_change_marker(pos, old_feature, new_feature, duration,
-                                      change_type, mon_num);
+                                      change_type, mon_num, colour);
     return mark;
 }
 
diff --git a/crawl-ref/source/mapmark.h b/crawl-ref/source/mapmark.h
index 4632b4cef2..d02d0718c8 100644
--- a/crawl-ref/source/mapmark.h
+++ b/crawl-ref/source/mapmark.h
@@ -196,7 +196,7 @@ public:
                     dungeon_feature_type oldfeat = DNGN_FLOOR,
                     dungeon_feature_type newfeat = DNGN_FLOOR,
                     int dur = 0, terrain_change_type type = TERRAIN_CHANGE_GENERIC,
-                    int mnum = 0);
+                    int mnum = 0, int oldcol = BLACK);
 
     void write (writer &) const;
     void read (reader &);
@@ -211,6 +211,7 @@ public:
     dungeon_feature_type old_feature;
     dungeon_feature_type new_feature;
     terrain_change_type  change_type;
+    int colour;
 };
 
 class map_cloud_spreader_marker : public map_marker
diff --git a/crawl-ref/source/tag-version.h b/crawl-ref/source/tag-version.h
index 95128fe337..8d34fecc06 100644
--- a/crawl-ref/source/tag-version.h
+++ b/crawl-ref/source/tag-version.h
@@ -111,6 +111,7 @@ enum tag_minor_version
     TAG_MINOR_SLAYRING_PLUSES,     // Combine Acc/Dam on rings of slaying and artefacts.
     TAG_MINOR_MERGE_EW,            // Combine enchant weapons scrolls.
     TAG_MINOR_WEAPON_PLUSES,       // Combine to-hit/to-dam enchantment on weapons.
+    TAG_MINOR_SAVE_TERRAIN_COLOUR, // Save colour in terrain-change markers.
 #endif
     NUM_TAG_MINORS,
     TAG_MINOR_VERSION = NUM_TAG_MINORS - 1
diff --git a/crawl-ref/source/terrain.cc b/crawl-ref/source/terrain.cc
index 2236bd8cf5..eb91c6e0f7 100644
--- a/crawl-ref/source/terrain.cc
+++ b/crawl-ref/source/terrain.cc
@@ -1001,7 +1001,8 @@ void dungeon_terrain_changed(const coord_def &pos,
                              dungeon_feature_type nfeat,
                              bool affect_player,
                              bool preserve_features,
-                             bool preserve_items)
+                             bool preserve_items,
+                             int colour)
 {
     if (grd(pos) == nfeat)
         return;
@@ -1016,7 +1017,7 @@ void dungeon_terrain_changed(const coord_def &pos,
         unnotice_feature(level_pos(level_id::current(), pos));
 
         grd(pos) = nfeat;
-        env.grid_colours(pos) = BLACK;
+        env.grid_colours(pos) = colour;
         // Reset feature tile
         env.tile_flv(pos).feat = 0;
         env.tile_flv(pos).feat_idx = 0;
@@ -1804,10 +1805,10 @@ void temp_change_terrain(coord_def pos, dungeon_feature_type newfeat, int dur,
     if (grd(pos) == newfeat && newfeat == old_feat)
         return;
 
+    int col = env.grid_colours(pos);
     map_terrain_change_marker *marker =
-        new map_terrain_change_marker(pos, old_feat, newfeat, dur, type);
-    if (mon)
-        marker->mon_num = mon->mid;
+        new map_terrain_change_marker(pos, old_feat, newfeat, dur, type,
+                                      mon ? mon->mid : 0, col);
     env.markers.add(marker);
     env.markers.clear_need_activate();
     dungeon_terrain_changed(pos, newfeat, true, false, true);
@@ -1860,6 +1861,7 @@ bool revert_terrain_change(coord_def pos, terrain_change_type ctype)
 {
     vector<map_marker*> markers = env.markers.get_markers_at(pos);
     dungeon_feature_type newfeat = DNGN_UNSEEN;
+    int colour = BLACK;
 
     for (int i = 0, size = markers.size(); i < size; ++i)
     {
@@ -1870,12 +1872,20 @@ bool revert_terrain_change(coord_def pos, terrain_change_type ctype)
 
             if (marker->change_type == ctype)
             {
+                if (marker->colour != BLACK)
+                    colour = marker->colour;
                 if (!newfeat)
                     newfeat = marker->old_feature;
                 env.markers.remove(marker);
             }
             else
+            {
+                // If we had an old colour, give it to the other marker.
+                if (colour != BLACK)
+                    marker->colour = colour;
+                colour = BLACK;
                 newfeat = marker->new_feature;
+            }
         }
     }
 
@@ -1885,7 +1895,7 @@ bool revert_terrain_change(coord_def pos, terrain_change_type ctype)
 
     if (newfeat != DNGN_UNSEEN)
     {
-        dungeon_terrain_changed(pos, newfeat, true, false, true);
+        dungeon_terrain_changed(pos, newfeat, true, false, true, colour);
         return true;
     }
     else
diff --git a/crawl-ref/source/terrain.h b/crawl-ref/source/terrain.h
index a6fcf969b5..9a142df35e 100644
--- a/crawl-ref/source/terrain.h
+++ b/crawl-ref/source/terrain.h
@@ -91,7 +91,8 @@ void dungeon_terrain_changed(const coord_def &pos,
                              dungeon_feature_type feat = DNGN_UNSEEN,
                              bool affect_player = true,
                              bool preserve_features = false,
-                             bool preserve_items = false);
+                             bool preserve_items = false,
+                             int colour = BLACK);
 
 // Moves everything on the level at src to dst.
 void dgn_move_entities_at(coord_def src,