minimal spanning tree implemented

no disconnected rooms

Cargo.lock

@@ -86,10 +86,23 @@ name = "el_diabolo"
 version = "0.1.0"
 dependencies = [
  "crossterm",
+ "petgraph",
  "rand",
  "ratatui",
 ]
 
+[[package]]
+name = "equivalent"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
+
+[[package]]
+name = "fixedbitset"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
+
 [[package]]
 name = "getrandom"
 version = "0.2.11"
@@ -117,6 +130,16 @@ version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
 
+[[package]]
+name = "indexmap"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d530e1a18b1cb4c484e6e34556a0d948706958449fca0cab753d649f2bce3d1f"
+dependencies = [
+ "equivalent",
+ "hashbrown",
+]
+
 [[package]]
 name = "indoc"
 version = "2.0.4"
@@ -210,6 +233,16 @@ version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "de3145af08024dea9fa9914f381a17b8fc6034dfb00f3a84013f7ff43f29ed4c"
 
+[[package]]
+name = "petgraph"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1d3afd2628e69da2be385eb6f2fd57c8ac7977ceeff6dc166ff1657b0e386a9"
+dependencies = [
+ "fixedbitset",
+ "indexmap",
+]
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.17"

Cargo.toml

@@ -9,3 +9,4 @@ edition = "2021"
 ratatui = "0.24.0"
 crossterm = "0.27.0"
 rand = "0.8.5"
+petgraph = "0.6.4"

src/level_generator.rs

@@ -1,5 +1,10 @@
 use rand::prelude::SliceRandom;
 use rand::Rng;
+use petgraph::graph::UnGraph;
+use petgraph::graph::Graph;
+use petgraph::data::*;
+use petgraph::algo::min_spanning_tree;
+use rand::rngs::ThreadRng;
 
 use crate::level::{Level, LevelElement, RoomType};
 
@@ -15,9 +20,9 @@ struct Room {
     pub offset_y: usize,
     pub width: usize,
     pub height: usize,
-    pub connection_down: bool,
+    // pub connection_down: bool,
-    pub connection_right: bool,
+    // pub connection_right: bool,
-    pub connected: bool,
+    // pub connected: bool,
 }
 
 impl Room {
@@ -28,11 +33,20 @@ impl Room {
             offset_y: 0,
             width: 0,
             height: 0,
-            connection_down: false,
+            // connection_down: false,
-            connection_right: false,
+            // connection_right: false,
-            connected: false,
+            // connected: false,
         }
     }
+    /// change the size and position of a room randomly within its bounds
+    fn random(&mut self, rng: &mut ThreadRng) {
+        let width = rng.gen_range(3..6);
+        let height = rng.gen_range(3..5);
+        self.width = width;
+        self.height = height;
+        self.offset_x = rng.gen_range(0..(ROOM_WIDTH - width));
+        self.offset_y = rng.gen_range(0..(ROOM_HEIGHT - height));
+    }
 }
 
 #[derive(Debug)]
@@ -42,74 +56,114 @@ pub struct LevelGenerator {
 
 impl LevelGenerator {
     pub fn generate(level: usize) -> Self {
-        let mut room_types: Vec<RoomType> = Vec::with_capacity(ROOMS_HORIZONTAL * ROOMS_VERTICAL);
-        if level > 0 {
-            room_types.push(RoomType::StairUp);
-        } else {
-            room_types.push(RoomType::Start);
-        }
-        if level < 24 {
-            room_types.push(RoomType::StairDown);
-        } else {
-            room_types.push(RoomType::End);
-        }
         let mut rng = rand::thread_rng();
+        let mut rooms = [[Room::new(); ROOMS_HORIZONTAL]; ROOMS_VERTICAL];
+        let mut graph = UnGraph::<(usize, usize), u16>::default();
+
+        // trick the room_connectable function into failing on the first iteration
+        rooms[0][0].kind = RoomType::BasicRoom;
+
+        while !LevelGenerator::rooms_connectable(&rooms) {
+            let mut room_types: Vec<RoomType> = Vec::with_capacity(ROOMS_HORIZONTAL * ROOMS_VERTICAL);
+            // level 0 contains a start room, all others contain a stair up
+            if level == 0 {
+                room_types.push(RoomType::Start);
+            } else {
+                room_types.push(RoomType::StairUp);
+            }
+            // level 24 (the last) contains an end room, all others a stair down
+            if level == 24 {
+                room_types.push(RoomType::End);
+            } else {
+                room_types.push(RoomType::StairDown);
+            }
+            // generate a random set of rooms and shuffle them
             for _ in room_types.len()..ROOMS_HORIZONTAL * ROOMS_VERTICAL {
                 match rng.gen_range(1..=6) {
+                    // TODO tune room type distribution
                     1..=3 => { room_types.push(RoomType::EmptyRoom) }
                     _ => { room_types.push(RoomType::BasicRoom) }
                 }
             }
             room_types.shuffle(&mut rng);
 
-        let mut rooms = [[Room::new(); ROOMS_HORIZONTAL]; ROOMS_VERTICAL];
+            graph.clear();
-        for r in 0..ROOMS_VERTICAL {
+            // place the rooms in the array an add nodes to the graph for every non empty room
-            for c in 0..ROOMS_HORIZONTAL {
+            for c in 0..ROOMS_VERTICAL {
-                rooms[r][c].kind = room_types.pop().unwrap();
+                for r in 0..ROOMS_HORIZONTAL {
-                if rooms[r][c].kind != RoomType::EmptyRoom {
+                    rooms[c][r].kind = room_types.pop().unwrap();
-                    let width = rng.gen_range(3..6);
+                    if rooms[c][r].kind != RoomType::EmptyRoom {
-                    let height = rng.gen_range(3..5);
+                        rooms[c][r].random(&mut rng);
-                    rooms[r][c].width = width;
+                        graph.add_node((c, r));
-                    rooms[r][c].height = height;
-                    rooms[r][c].offset_x = rng.gen_range(0..(ROOM_WIDTH - width));
-                    rooms[r][c].offset_y = rng.gen_range(0..(ROOM_HEIGHT - height));
                     }
-                if r == ROOMS_HORIZONTAL - 1 || c == ROOMS_HORIZONTAL - 1 {
-                    continue;
-                }
-                match rng.gen_range(0..3) {
-                    0 => { rooms[r][c].connection_down = true }
-                    1 => { rooms[r][c].connection_right = true }
-                    2 => {
-                        rooms[r][c].connection_down = true;
-                        rooms[r][c].connection_down = true
-                    }
-                    _ => {}
                 }
             }
         }
 
-        let mut unconnected_rooms = 0;//ROOMS_HORIZONTAL * ROOMS_VERTICAL - 1;
+        // add edges to the graph connecting each room to all of its neighbours (max 4 of them)
-        rooms[0][0].connected = true;
+        for c in 0..ROOMS_VERTICAL {
-        for r in 0..ROOMS_VERTICAL {
+            for r in 0..ROOMS_HORIZONTAL {
-            for c in 0..ROOMS_HORIZONTAL {
+                if rooms[c][r].kind == RoomType::EmptyRoom {
-                if !rooms[r][c].connected {
                     continue;
                 }
-                if rooms[r][c].connection_right {
+                let src_index = graph.node_indices().find(|i| graph[*i] == (c, r)).unwrap();
-                    rooms[r][c + 1].connected = true;
+                for r_1 in r + 1..ROOMS_HORIZONTAL {
+                    if rooms[c][r_1].kind != RoomType::EmptyRoom {
+                        let tgt_index = graph.node_indices().find(|i| graph[*i] == (c, r_1)).unwrap();
+                        // todo use random weight for edge
+                        graph.add_edge(src_index, tgt_index, 1);
+                        break;
                     }
-                if rooms[r][c].connection_down {
+                }
-                    rooms[r + 1][c].connected = true;
+                for c_1 in c + 1..ROOMS_VERTICAL {
+                    if rooms[c_1][r].kind != RoomType::EmptyRoom {
+                        let tgt_index = graph.node_indices().find(|i| graph[*i] == (c_1, r)).unwrap();
+                        // todo use random weight for edge
+                        graph.add_edge(src_index, tgt_index, 1);
+                        break;
                     }
                 }
             }
-        println!("Unconnected: {}", unconnected_rooms);
+        }
+
+        // calculate a minimum spanning tree
+        let mst: Graph<(usize, usize), u16, petgraph::Undirected> = Graph::from_elements(min_spanning_tree(&graph));
+        for edge in mst.raw_edges() {
+            let src = mst[edge.source()];
+            let tgt = mst[edge.target()];
+            println!("{:?} {:?}", src, tgt);
+        }
+        // println!("Level {}\n{}", level, Dot::new(&mst));
 
         LevelGenerator {
             rooms
         }
     }
+    /// Verifies that for a given matrix of rooms each room has at least one other room in the
+    /// same row or column.
+    fn rooms_connectable(rooms: &[[Room; ROOMS_HORIZONTAL]; ROOMS_VERTICAL]) -> bool {
+        for c in 0..ROOMS_VERTICAL {
+            for r in 0..ROOMS_HORIZONTAL {
+                if rooms[c][r].kind != RoomType::EmptyRoom {
+                    let mut connected = 0;
+                    for c1 in 0..ROOMS_VERTICAL {
+                        if rooms[c1][r].kind != RoomType::EmptyRoom {
+                            connected += 1;
+                        }
+                    }
+                    for r1 in 0..ROOMS_HORIZONTAL {
+                        if rooms[c][r1].kind != RoomType::EmptyRoom {
+                            connected += 1;
+                        }
+                    }
+                    if connected <= 2 {
+                        return false;
+                    }
+                }
+            }
+        }
+        return true;
+    }
     pub fn render(&self) -> Level {
         let mut rng = rand::thread_rng();
         let mut s = [[LevelElement::Wall; 1 + ROOMS_HORIZONTAL * ROOM_HEIGHT]; 1 + ROOMS_VERTICAL * ROOM_WIDTH];