prevent player from leaving the field

src/level.rs

@@ -164,6 +164,7 @@ impl Level {
         let new_x: usize = (agent_pos.get_x() as i16 + dx) as usize;
         let new_y: usize = (agent_pos.get_y() as i16 + dy) as usize;
 
+        // verify we cannot leave the playing field
         if new_x >= LEVEL_WIDTH || new_y >= LEVEL_HEIGHT {
             return false;
         }
@@ -178,6 +179,12 @@ impl Level {
         let agent_pos = agent.get_immutable_position();
         let new_x: usize = (agent_pos.get_x() as i16 + dx) as usize;
         let new_y: usize = (agent_pos.get_y() as i16 + dy) as usize;
+
+        // verify we cannot leave the playing field
+        if new_x >= LEVEL_WIDTH || new_y >= LEVEL_HEIGHT {
+            return false;
+        }
+
         self.structure[new_x][new_y] != StructureElement::Wall
     }
     #[cfg(test)]