add a brown rock

src/world.rs

@@ -42,18 +42,37 @@ pub fn setup(
     // Add spheres
     let sphere_radius = 50.0;
     let sphere_handle = meshes.add(Sphere::new(sphere_radius));
-    let white_handle = materials.add(StandardMaterial {
+    let gray = materials.add(StandardMaterial {
         base_color: Color::GRAY,
         perceptual_roughness: 1.0,
         ..default()
     });
+    let brown = materials.add(StandardMaterial {
+        base_color: Color::Rgba { alpha: 0.5, red: 0.8, green: 0.5, blue: 0.1 },
+        perceptual_roughness: 1.0,
+        ..default()
+    });
+
     commands.spawn(PbrBundle {
         mesh: sphere_handle.clone(),
-        material: white_handle.clone(),
+        material: gray.clone(),
         transform: Transform::from_xyz(
             0.0,
             0.0,
-            -200.0,
+            -500.0,
+        ),
+        ..default()
+    });
+
+    let sphere_radius = 10.0;
+    let sphere_handle = meshes.add(Sphere::new(sphere_radius));
+    commands.spawn(PbrBundle {
+        mesh: sphere_handle.clone(),
+        material: brown.clone(),
+        transform: Transform::from_xyz(
+            300.0,
+            40.0,
+            250.0,
         ),
         ..default()
     });