Fix map size width

src/main.rs

@@ -9,6 +9,10 @@ mod prelude {
     pub use crate::resources::*;
     pub use crate::systems::*;
     pub use bevy::prelude::*;
+
+    pub const SCREEN_WIDTH: f32 = 80.0;
+    pub const SCREEN_HEIGHT: f32 = 50.0;
+    pub const TILE_SIZE: f32 = 64.0;
 }
 
 use prelude::*;
@@ -20,5 +24,6 @@ fn main() {
         .add_startup_system(setup.system())
         .add_startup_system(add_player.system())
         .add_system(player_movement.system())
+        .add_system(follow_player.system())
         .run();
 }

src/systems/mod.rs

@@ -1,4 +1,5 @@
 use crate::prelude::*;
+use bevy::render::camera::Camera;
 
 pub fn setup(
     mut commands: Commands,
@@ -10,9 +11,9 @@ pub fn setup(
 
     // Map
     let grass_material = materials.add(asset_server.load("grass.png").into());
-    let tile_size = Vec2::new(32.0, 32.0);
+    let tile_size = Vec2::new(TILE_SIZE, TILE_SIZE);
     let sprite = Sprite::new(tile_size);
-    let map_size = Vec2::new(80.0, 50.0);
+    let map_size = Vec2::new(SCREEN_WIDTH, SCREEN_HEIGHT);
     let half_x = (map_size.x / 2.0) as i32;
     let half_y = (map_size.y / 2.0) as i32;
 
@@ -36,15 +37,15 @@ pub fn add_player(
     asset_server: Res<AssetServer>,
     mut materials: ResMut<Assets<ColorMaterial>>,
 ) {
-    let player_sprite = materials.add(asset_server.load("marshmallow.png").into());
+    let player_material = materials.add(asset_server.load("marshmallow.png").into());
 
     commands
         .spawn()
         .insert(Player)
         .insert(Name("Player 1".to_string()))
         .insert_bundle(SpriteBundle {
-            material: player_sprite,
-            sprite: Sprite::new(Vec2::new(64.0, 64.0)),
+            material: player_material,
+            sprite: Sprite::new(Vec2::new(TILE_SIZE, TILE_SIZE)),
             transform: Transform::from_translation(Vec3::new(0.0, 0.0, 1.0)),
             ..Default::default()
         });
@@ -74,8 +75,26 @@ pub fn player_movement(
         let translation = &mut transform.translation;
         let delta_seconds = time.delta_seconds();
 
-        translation.x += delta_seconds * direction.x * 100.0;
-        translation.y += delta_seconds * direction.y * 100.0;
+        translation.x += delta_seconds * direction.x * 300.0;
+        translation.y += delta_seconds * direction.y * 300.0;
+    }
+}
+
+pub fn follow_player(
+    mut q: QuerySet<(
+        Query<&Transform, With<Player>>,
+        Query<&mut Transform, With<Camera>>,
+    )>,
+) {
+    if let Ok(player_transform) = q.q0().single() {
+        let player_translation = player_transform.translation;
+
+        if let Ok(mut camera_transform) = q.q1_mut().single_mut() {
+            let camera_translation = &mut camera_transform.translation;
+
+            camera_translation.x = player_translation.x;
+            camera_translation.y = player_translation.y;
+        }
     }
 }