Refactors worldmap gen, now uses a master list of maps for backtracking

src/map/dungeon.rs

@@ -1,5 +1,8 @@
-use super::Map;
+use super::{Map, TileType};
+use crate::{gamelog, map_builders, Position, Telepath, Viewshed};
+use rltk::prelude::*;
 use serde::{Deserialize, Serialize};
+use specs::prelude::*;
 use std::collections::HashMap;
 
 #[derive(Default, Serialize, Deserialize, Clone)]
@@ -27,3 +30,103 @@ impl MasterDungeonMap {
         }
     }
 }
+
+pub fn level_transition(ecs: &mut World, new_id: i32) -> Option<Vec<Map>> {
+    // Obtain master
+    let dungeon_master = ecs.read_resource::<MasterDungeonMap>();
+    if dungeon_master.get_map(new_id).is_some() {
+        std::mem::drop(dungeon_master);
+        transition_to_existing_map(ecs, new_id);
+        return None;
+    } else {
+        std::mem::drop(dungeon_master);
+        return Some(transition_to_new_map(ecs, new_id));
+    }
+}
+
+fn transition_to_existing_map(ecs: &mut World, new_id: i32) {
+    let dungeon_master = ecs.read_resource::<MasterDungeonMap>();
+    // Unwrapping here panics if new_id isn't present. But this should
+    // never be called without new_id being present by level_transition.
+    let map = dungeon_master.get_map(new_id).unwrap();
+    let mut worldmap_resource = ecs.write_resource::<Map>();
+    let player_entity = ecs.fetch::<Entity>();
+    // Find down stairs, place player
+    let w = map.width;
+    for (idx, tt) in map.tiles.iter().enumerate() {
+        if *tt == TileType::DownStair {
+            let mut player_position = ecs.write_resource::<Point>();
+            *player_position = Point::new(idx as i32 % w, idx as i32 / w);
+            let mut position_components = ecs.write_storage::<Position>();
+            let player_pos_component = position_components.get_mut(*player_entity);
+            if let Some(player_pos_component) = player_pos_component {
+                player_pos_component.x = idx as i32 % w;
+                player_pos_component.y = idx as i32 / w;
+            }
+        }
+    }
+    *worldmap_resource = map;
+    // Dirtify viewsheds (forces refresh)
+    let mut viewshed_components = ecs.write_storage::<Viewshed>();
+    let mut telepath_components = ecs.write_storage::<Telepath>();
+    let vision_vs = viewshed_components.get_mut(*player_entity);
+    let telepath_vs = telepath_components.get_mut(*player_entity);
+    if let Some(vs) = vision_vs {
+        vs.dirty = true;
+    }
+    if let Some(vs) = telepath_vs {
+        vs.dirty = true;
+    }
+}
+
+fn transition_to_new_map(ecs: &mut World, new_id: i32) -> Vec<Map> {
+    let mut rng = ecs.write_resource::<rltk::RandomNumberGenerator>();
+    // Might need this to fallback to 1, but if player
+    // level isn't found at all, there's a bigger concern
+    // concern than just this function not working.
+    let player_level = gamelog::get_event_count("player_level");
+    let mut builder = map_builders::level_builder(new_id, &mut rng, 100, 50, player_level);
+    builder.build_map(&mut rng);
+    std::mem::drop(rng);
+    if new_id > 1 {
+        if let Some(pos) = &builder.build_data.starting_position {
+            let up_idx = builder.build_data.map.xy_idx(pos.x, pos.y);
+            builder.build_data.map.tiles[up_idx] = TileType::UpStair;
+        }
+    }
+    let mapgen_history = builder.build_data.history.clone();
+    let player_start;
+    {
+        let mut worldmap_resource = ecs.write_resource::<Map>();
+        *worldmap_resource = builder.build_data.map.clone();
+        // Unwrap so we get a CTD if there's no starting pos.
+        player_start = builder.build_data.starting_position.as_mut().unwrap().clone();
+    }
+    // Spawn entities
+    builder.spawn_entities(ecs);
+    // Place player and update resources
+    let mut player_position = ecs.write_resource::<Point>();
+    *player_position = Point::new(player_start.x, player_start.y);
+    let mut position_components = ecs.write_storage::<Position>();
+    let player_entity = ecs.fetch::<Entity>();
+    let player_pos_component = position_components.get_mut(*player_entity);
+    if let Some(player_pos_component) = player_pos_component {
+        player_pos_component.x = player_start.x;
+        player_pos_component.y = player_start.y;
+    }
+    // Mark viewshed as dirty (force refresh)
+    let mut viewshed_components = ecs.write_storage::<Viewshed>();
+    let mut telepath_components = ecs.write_storage::<Telepath>();
+    let vision_vs = viewshed_components.get_mut(*player_entity);
+    let telepath_vs = telepath_components.get_mut(*player_entity);
+    if let Some(vs) = vision_vs {
+        vs.dirty = true;
+    }
+    if let Some(vs) = telepath_vs {
+        vs.dirty = true;
+    }
+    // Store newly minted map
+    let mut dungeon_master = ecs.write_resource::<MasterDungeonMap>();
+    dungeon_master.store_map(&builder.build_data.map);
+    return mapgen_history;
+}