Many more Rubocop-inspired code improvements

Data/Scripts/004_Game classes/002_Game_System.rb

@@ -132,12 +132,11 @@ class Game_System
 
   def setDefaultBGM(bgm, volume = 80, pitch = 100)
     bgm = RPG::AudioFile.new(bgm, volume, pitch) if bgm.is_a?(String)
+    @defaultBGM = nil
     if bgm != nil && bgm.name != ""
-      @defaultBGM = nil
       self.bgm_play(bgm)
       @defaultBGM = bgm.clone
     else
-      @defaultBGM = nil
       self.bgm_play(@playing_bgm)
     end
   end

Data/Scripts/004_Game classes/004_Game_Map.rb

@@ -357,7 +357,7 @@ class Game_Map
 
   def start_scroll(direction, distance, speed)
     @scroll_direction = direction
-    if direction == 2 || direction == 8   # down or up
+    if [2, 8].include?(direction)   # down or up
       @scroll_rest = distance * REAL_RES_Y
     else
       @scroll_rest = distance * REAL_RES_X

Data/Scripts/004_Game classes/006_Game_MapFactory.rb

@@ -394,9 +394,9 @@ class PokemonMapFactory
       return
     end
     setMapsInRange
-    deleted = false
-    deleted = @maps.delete_if { |map| !MapFactoryHelper.mapInRange?(map) }
-    @mapIndex = getMapIndex($game_map.map_id) if deleted
+    old_num_maps = @maps.length
+    @maps.delete_if { |map| !MapFactoryHelper.mapInRange?(map) }
+    @mapIndex = getMapIndex($game_map.map_id) if @maps.length != old_num_maps
   end
 end
 
@@ -476,7 +476,7 @@ module MapFactoryHelper
   # Returns the X or Y coordinate of an edge on the map with id.
   # Considers the special strings "N","W","E","S"
   def self.getMapEdge(id, edge)
-    return 0 if edge == "N" || edge == "W"
+    return 0 if ["N", "W"].include?(edge)
     dims = getMapDims(id)   # Get dimensions
     return dims[0] if edge == "E"
     return dims[1] if edge == "S"

Data/Scripts/004_Game classes/007_Game_Character.rb

@@ -201,7 +201,6 @@ class Game_Character
       @bush_depth = 0
       return
     end
-    deep_bush = regular_bush = false
     xbehind = @x + (@direction == 4 ? 1 : @direction == 6 ? -1 : 0)
     ybehind = @y + (@direction == 8 ? 1 : @direction == 2 ? -1 : 0)
     this_map = (self.map.valid?(@x, @y)) ? [self.map, @x, @y] : $map_factory&.getNewMap(@x, @y)
@@ -738,7 +737,7 @@ class Game_Character
     end
     @x = @x + x_plus
     @y = @y + y_plus
-    real_distance = Math::sqrt(x_plus * x_plus + y_plus * y_plus)
+    real_distance = Math.sqrt(x_plus * x_plus + y_plus * y_plus)
     distance = [1, real_distance].max
     @jump_peak = distance * Game_Map::TILE_HEIGHT * 3 / 8   # 3/4 of tile for ledge jumping
     @jump_distance = [x_plus.abs * Game_Map::REAL_RES_X, y_plus.abs * Game_Map::REAL_RES_Y].max

Data/Scripts/004_Game classes/008_Game_Event.rb

@@ -168,11 +168,12 @@ class Game_Event < Game_Character
   end
 
   def check_event_trigger_auto
-    if @trigger == 2      # Event touch
+    case @trigger
+    when 2   # Event touch
       if at_coordinate?($game_player.x, $game_player.y)
         start if !jumping? && over_trigger?
       end
-    elsif @trigger == 3   # Autorun
+    when 3   # Autorun
       start
     end
   end

Data/Scripts/004_Game classes/009_Game_Player.rb

@@ -157,7 +157,7 @@ class Game_Player < Game_Character
     end
     @x = @x + x_plus
     @y = @y + y_plus
-    real_distance = Math::sqrt(x_plus * x_plus + y_plus * y_plus)
+    real_distance = Math.sqrt(x_plus * x_plus + y_plus * y_plus)
     distance = [1, real_distance].max
     @jump_peak = distance * Game_Map::TILE_HEIGHT * 3 / 8   # 3/4 of tile for ledge jumping
     @jump_distance = [x_plus.abs * Game_Map::REAL_RES_X, y_plus.abs * Game_Map::REAL_RES_Y].max