Bring back random tree colour generation

Wasm can't use thread_rng so we're creating a new "one-off" rng for
things that shouldn't affect the replay.

src/generators/forrest.rs

@@ -1,5 +1,6 @@
 use generators::GeneratedWorld;
 
+use color;
 use formula;
 use item::{self, Item};
 use level::{Tile, TileKind};
@@ -12,7 +13,7 @@ use rand::distributions::{IndependentSample, Weighted, WeightedChoice};
 // TODO: Instead of `map_size`, use a Rectangle with the world
 // positions here. We want to expose the non-world coordinates in as
 // few places as possible.
-fn generate_map<R: Rng>(rng: &mut R, map_size: Point, player_pos: Point) -> Vec<(Point, Tile)> {
+fn generate_map<R: Rng, G: Rng>(rng: &mut R, one_off_rng: &mut G, map_size: Point, player_pos: Point) -> Vec<(Point, Tile)> {
     let mut weights = [
         Weighted {
             weight: 610,
@@ -37,7 +38,14 @@ fn generate_map<R: Rng>(rng: &mut R, map_size: Point, player_pos: Point) -> Vec<
                 true => TileKind::Empty,
                 false => opts.ind_sample(rng),
             };
-            result.push((Point::new(x, y), Tile::new(kind)));
+
+            let mut tile = Tile::new(kind);
+            if tile.kind == TileKind::Tree {
+                let options = [color::tree_1, color::tree_2, color::tree_3];
+                tile.fg_color = *one_off_rng.choose(&options).unwrap();
+            }
+
+            result.push((Point::new(x, y), tile));
         }
     }
     result
@@ -202,8 +210,8 @@ fn generate_items<R: Rng>(rng: &mut R, map: &[(Point, Tile)]) -> Vec<(Point, Ite
 }
 
 
-pub fn generate<R: Rng>(rng: &mut R, size: Point, player: Point) -> GeneratedWorld {
-    let map = generate_map(rng, size, player);
+pub fn generate<R: Rng, G: Rng>(rng: &mut R, one_off_rng: &mut G, size: Point, player: Point) -> GeneratedWorld {
+    let map = generate_map(rng, one_off_rng, size, player);
     let monsters = generate_monsters(rng, &map);
     let items = generate_items(rng, &map);
     (map, monsters, items)

src/level.rs

@@ -4,7 +4,6 @@ use graphics::Render;
 use item::Item;
 use point;
 
-use rand::{self, Rng};
 use std::collections::HashMap;
 use std::time::Duration;
 
@@ -46,11 +45,7 @@ impl Tile {
     pub fn new(kind: TileKind) -> Tile {
         let color = match kind {
             TileKind::Empty => color::empty_tile,
-            TileKind::Tree => {
-                let options = [color::tree_1, color::tree_2, color::tree_3];
-                //*rand::thread_rng().choose(&options).unwrap()
-                color::tree_1
-            }
+            TileKind::Tree => color::tree_1,
         };
         Tile {
             kind,

src/state.rs

@@ -5,7 +5,7 @@ use monster;
 use player::Player;
 use point::Point;
 use util;
-use rand::{self, IsaacRng, SeedableRng};
+use rand::{IsaacRng, SeedableRng};
 
 use stats::Stats;
 use std::collections::VecDeque;

src/world.rs

@@ -37,8 +37,9 @@ impl Chunk {
             monsters: vec![],
         };
 
+        let mut one_off_rng = chunk.rng.clone();
         let generated_data =
-            generators::forrest::generate(&mut chunk.rng, chunk.level.size(), player_position);
+            generators::forrest::generate(&mut chunk.rng, &mut one_off_rng, chunk.level.size(), player_position);
 
         chunk.populate(generated_data);