feat(content, port): port treetops and ability to climb trees from DDA

data/json/furniture_and_terrain/terrain-roofs.json

@@ -269,5 +269,45 @@
       "sound_fail_vol": 4,
       "bash_below": true
     }
+  },
+  {
+    "type": "terrain",
+    "id": "t_treetop",
+    "name": "treetop",
+    "description": "The upper branches of a tree.  There's just enough room to perch here.",
+    "symbol": "#",
+    "color": [ "light_green", "green", "yellow_yellow", "brown" ],
+    "move_cost": 8,
+    "flags": [ "TRANSPARENT", "FLAMMABLE_ASH", "UNSTABLE", "SINGLE_SUPPORT" ]
+  },
+  {
+    "type": "terrain",
+    "id": "t_treetop_evergreen",
+    "name": "treetop",
+    "description": "The upper branches of a tree.  There's just enough room to perch here.",
+    "symbol": "#",
+    "color": [ "green" ],
+    "move_cost": 8,
+    "flags": [ "TRANSPARENT", "FLAMMABLE_ASH", "UNSTABLE", "SINGLE_SUPPORT" ]
+  },
+  {
+    "type": "terrain",
+    "id": "t_treetop_dead",
+    "name": "dead treetop",
+    "description": "The bare upper branches of a dead tree.  There's just enough room to perch here.",
+    "symbol": "#",
+    "color": "brown",
+    "move_cost": 8,
+    "flags": [ "TRANSPARENT", "FLAMMABLE_ASH", "UNSTABLE", "SINGLE_SUPPORT" ]
+  },
+  {
+    "type": "terrain",
+    "id": "t_treetop_giant_fern",
+    "name": "giant fern top",
+    "description": "The top of some unearthly gigantic fern.  There is enough room to perch up here, but only just.",
+    "symbol": "#",
+    "color": "red",
+    "move_cost": 8,
+    "flags": [ "TRANSPARENT", "FLAMMABLE_ASH", "UNSTABLE", "SINGLE_SUPPORT" ]
   }
 ]

src/activity_handlers.cpp

@@ -4018,6 +4018,7 @@ void activity_handlers::chop_tree_finish( player_activity *act, player *p )
 
     here.ter_set( pos, t_stump );
     p->add_msg_if_player( m_good, _( "You finish chopping down a tree." ) );
+    here.collapse_at( pos, false, true, false );
     // sound of falling tree
     sfx::play_variant_sound( "misc", "timber",
                              sfx::get_heard_volume( here.getlocal( act->placement ) ) );

src/game.cpp

@@ -10015,6 +10015,7 @@ void game::vertical_move( int movez, bool force, bool peeking )
     if( m.has_zlevels() && !force && movez == 1 && !m.has_flag( "GOES_UP", u.pos() ) &&
         !u.is_underwater() ) {
         // Climbing
+
         if( m.has_floor_or_support( stairs ) ) {
             add_msg( m_info, _( "You can't climb here - there's a ceiling above your head." ) );
             return;

src/map.cpp

@@ -2925,24 +2925,34 @@ int map::collapse_check( const tripoint &p )
     // if there's support below, things are less likely to collapse
     if( p.z > -OVERMAP_DEPTH ) {
         const tripoint &pbelow = tripoint( p.xy(), p.z - 1 );
-        for( const tripoint &tbelow : points_in_radius( pbelow, 1 ) ) {
+        if( has_flag( TFLAG_SINGLE_SUPPORT, p ) ) {
             if( has_flag( TFLAG_SUPPORTS_ROOF, pbelow ) ) {
-                num_supports += 1;
-                if( has_flag( TFLAG_WALL, pbelow ) ) {
-                    num_supports += 2;
-                }
-                if( tbelow == pbelow ) {
-                    num_supports += 2;
+                num_supports = 3;
+            } else {
+                num_supports = 0;
+            }
+        } else {
+            for( const tripoint &tbelow : points_in_radius( pbelow, 1 ) ) {
+                if( has_flag( TFLAG_SUPPORTS_ROOF, pbelow ) ) {
+                    num_supports += 1;
+                    if( has_flag( TFLAG_WALL, pbelow ) ) {
+                        num_supports += 2;
+                    }
+                    if( tbelow == pbelow ) {
+                        num_supports += 2;
+                    }
                 }
             }
         }
     }
 
     for( const tripoint &t : points_in_radius( p, 1 ) ) {
+        if( has_flag( TFLAG_SINGLE_SUPPORT, p ) ) {
+            break;
+        }
         if( p == t ) {
             continue;
         }
-
         if( collapses ) {
             if( has_flag( TFLAG_COLLAPSES, t ) ) {
                 num_supports++;
@@ -2997,13 +3007,14 @@ void map::collapse_at( const tripoint &p, const bool silent, const bool was_supp
             if( p != t && ( has_flag( TFLAG_SUPPORTS_ROOF, t ) && has_flag( TFLAG_COLLAPSES, t ) ) ) {
                 collapse_at( t, silent );
             }
-            // this tile used to support a roof, now it doesn't, which means there is only
-            // open air above us
-            if( zlevels ) {
-                ter_set( tz, t_open_air );
-                furn_set( tz, f_null );
-                propagate_suspension_check( tz );
-            }
+        }
+        // this tile used to support a roof, now it doesn't, which means there is only
+        // open air above us
+        if( zlevels ) {
+            const tripoint tabove( p.xy(), p.z + 1 );
+            ter_set( tabove, t_open_air );
+            furn_set( tabove, f_null );
+            propagate_suspension_check( tabove );
         }
     }
     // it would be great to check if collapsing ceilings smashed through the floor, but

src/mapdata.cpp

@@ -204,6 +204,8 @@ static const std::unordered_map<std::string, ter_bitflags> ter_bitflags_map = {
         { "FRIDGE",                   TFLAG_FRIDGE },         // This is an active fridge.
         { "FREEZER",                  TFLAG_FREEZER },        // This is an active freezer.
         { "ELEVATOR",                 TFLAG_ELEVATOR },       // This is an elevator.
+        { "SINGLE_SUPPORT",            TFLAG_SINGLE_SUPPORT},  // This is only supported from below.
+        { "CLIMB_ADJACENT",            TFLAG_CLIMB_ADJACENT},  // This is climbable when player is adjancent to it.
     }
 };
 

src/mapdata.h

@@ -328,7 +328,8 @@ enum ter_bitflags : int {
     TFLAG_FRIDGE,
     TFLAG_FREEZER,
     TFLAG_ELEVATOR,
-
+    TFLAG_SINGLE_SUPPORT,
+    TFLAG_CLIMB_ADJACENT,
     NUM_TERFLAGS
 };