Add rng seed

src/main.rs

@@ -10,6 +10,7 @@ struct State {
     view: Chunk,
     loaded_chunks: Box<HashMap<(i32, i32), Chunk>>,
     world_pos: (i32, i32),
+    seed: u64,
     player_position: usize,
     selected_object: Option<TileType>,
     visible: Vec<bool>,
@@ -17,6 +18,10 @@ struct State {
 
 impl State {
     pub fn new() -> State {
+        let seed = RandomNumberGenerator::new().rand::<u64>();
+        Self::seeded(seed)
+    }
+    pub fn seeded(seed: u64) -> State {
         let mut chunks: HashMap<(i32, i32), Chunk> = HashMap::new();
 
         // Coordinates of the current and surrounding chunks
@@ -33,8 +38,7 @@ impl State {
         ]
         .into();
         for key in keys {
-            let seed = RandomNumberGenerator::new().rand::<u64>();
-            let chunk = map::new_chunk(seed);
+            let chunk = map::new_chunk(seed, Point::from(key));
             chunks.insert(key, chunk);
         }
 
@@ -42,6 +46,7 @@ impl State {
             world_pos: (0, 0),
             view: chunks.get(&(0, 0)).unwrap().to_vec(),
             loaded_chunks: Box::new(chunks),
+            seed,
             player_position: (25 * 80) + 40, // Equivalent to point2d_to_index(40, 25) but we haven't initialized it yet
             visible: vec![false; 80 * 50],
             selected_object: None,
@@ -58,7 +63,7 @@ impl State {
         let chunk = match self.loaded_chunks.get(&self.world_pos) {
             Some(chunk) => chunk,
             None => {
-                let new_chunk = map::new_chunk(crypto::hash_to_number(&self.world_pos));
+                let new_chunk = map::new_chunk(self.seed, Point::from(self.world_pos));
                 self.loaded_chunks.insert(self.world_pos, new_chunk);
                 self.loaded_chunks
                     .get(&self.world_pos)

src/map.rs

@@ -1,3 +1,5 @@
+use crate::crypto;
+use rltk::Point;
 use rltk::RandomNumberGenerator;
 use std::fmt::Display;
 
@@ -18,12 +20,15 @@ impl Display for TileType {
     }
 }
 
-pub fn new_chunk(seed: u64) -> Chunk {
+pub fn new_chunk(seed: u64, pos: Point) -> Chunk {
     let mut map = vec![TileType::Floor; 80 * 50];
     let count = map.len();
 
-    // TODO: Lift seed to game state and pass to this method
-    let mut rng = RandomNumberGenerator::seeded(seed);
+    let pos_hash = crypto::hash_to_number(pos);
+
+    // Feed seed and world position into random generator.
+    // There might be a better way to do this, but I think this works for now.
+    let mut rng = RandomNumberGenerator::seeded(seed.max(pos_hash) - seed.min(pos_hash));
 
     // Place obstacles
     for _ in 0..20 {