PopulationConfig: make fields private

src/grid.rs

@@ -6,10 +6,10 @@ use std::fmt::{Display, Formatter};
 /// A population configuration.
 #[derive(Debug, Clone, Copy)]
 pub struct PopulationConfig {
-    pub sensor_distance: f32,
-    pub step_distance: f32,
-    pub sensor_angle: f32,
-    pub rotation_angle: f32,
+    sensor_distance: f32,
+    step_distance: f32,
+    sensor_angle: f32,
+    rotation_angle: f32,
 
     deposition_amount: f32,
 }