Add a surface/underground divide

src/app.rs

@@ -86,7 +86,7 @@ impl App {
     }
 
     fn do_rendering(&mut self) {
-        self.rw.clear(Color::BLACK);
+        self.rw.clear(Color::rgb(55, 221, 231));
         self.game.draw_world(&mut self.rw, &self.res);
         self.sf_egui
             .do_frame(|ctx| {

src/game.rs

@@ -4,7 +4,7 @@ use crate::{
     graphics::{ScreenPos, ScreenPosScalar, NATIVE_RESOLUTION},
     math::{wp_to_tp, WorldPos, WorldPosScalar},
     res::Res,
-    world::{TilePos, World},
+    world::{Tile, TilePos, World},
 };
 
 pub struct GameState {
@@ -16,7 +16,10 @@ impl GameState {
         let mut s = Sprite::with_texture(&res.tile_atlas);
         for_each_tile_on_screen(self.camera_offset, |tp, sp| {
             let tile = self.world.tile_at_mut(tp);
-            s.set_texture_rect(Rect::new(tile.id as i32 * 32, 0, 32, 32));
+            if tile.id == Tile::AIR {
+                return;
+            }
+            s.set_texture_rect(Rect::new((tile.id - 1) as i32 * 32, 0, 32, 32));
             s.set_position(sp.to_sf_vec());
             rw.draw(&s);
         });

src/world.rs

@@ -28,7 +28,7 @@ impl World {
     /// Loads or generates the containing chunk if necessary.
     pub fn tile_at_mut(&mut self, pos: TilePos) -> &mut Tile {
         let (chk, local) = pos.to_chunk_and_local();
-        let chk = self.chunks.entry(chk).or_insert_with(Chunk::new_rand);
+        let chk = self.chunks.entry(chk).or_insert_with(|| Chunk::gen(chk));
         chk.at_mut(local)
     }
 }
@@ -107,11 +107,13 @@ pub struct Chunk {
 }
 
 impl Chunk {
-    pub fn new_rand() -> Self {
+    pub fn gen(pos: ChunkPos) -> Self {
         let mut rng = thread_rng();
         let mut tiles = [Tile { id: 0 }; CHUNK_N_TILES];
-        for b in &mut tiles {
-            b.id = rng.gen_range(0..8);
+        if pos.y > 40 {
+            for b in &mut tiles {
+                b.id = rng.gen_range(1..5);
+            }
         }
         Self { tiles }
     }
@@ -127,3 +129,7 @@ type TileId = u16;
 pub struct Tile {
     pub id: TileId,
 }
+
+impl Tile {
+    pub const AIR: TileId = 0;
+}