[#176] Adding support for easing during scrolling

src/Commands.rb

@@ -2914,9 +2914,9 @@ def camera_scroll(direction, distance, speed)
       $game_map.start_scroll(direction, distance, speed)
     end
 
-    def camera_scroll_towards(x, y, nb_steps)
+    def camera_scroll_towards(x, y, nb_steps, easing = :InLinear)
       Fiber.yield while $game_map.scrolling?
-      $game_map.start_scroll_towards(x, y, nb_steps)
+      $game_map.start_scroll_towards(x, y, nb_steps, Easing::FUNCTIONS[easing])
     end
 
     def camera_move_on(x, y)

src/Doc.rb

@@ -44,7 +44,7 @@ module Doc
     :undocumented => "Commandes non documentées",
     :orphans      => "Commandes inconnues",
     :suggest      => "Suggestion",
-    :ease_desc    => "Fonction à utiliser pour effectuer la transition. :linear par défaut."
+    :ease_desc    => "Fonction à utiliser pour effectuer la transition. :InLinear par défaut."
   }
   documentation_add_link "GitHub", "https://github.com/RMEx/RME"
   documentation_add_link "Manuel d'utilisation (Wiki)", "https://github.com/RMEx/RME/wiki"
@@ -5714,7 +5714,7 @@ module Command
 		:x => ["L'abscisse du point cible", :Fixnum],
 		:y => ["L'ordonnée du point cible", :Fixnum],
 		:nb_steps => ["Le nombre d'étapes lors du défilement (plus il y en a, plus le temps de défilement sera long)", :Fixnum]
-
+		:easing_function => []
 	}
 register_command :camera,'Command.camera_scroll_towards'
 

src/EvEx.rb

@@ -2635,30 +2635,34 @@ def update_scroll
       @display_x = target.x
       @display_y = target.y
       @scroll_rest -= 1
+
       @scroll_function = nil if (0 >= @scroll_rest)
     end
   end
   #--------------------------------------------------------------------------
   # * Scroll straight towards the given point (x, y)
   #--------------------------------------------------------------------------
-  def start_scroll_towards(x, y, nb_steps)
+  def start_scroll_towards(x, y, nb_steps, easing_function)
     initial_point  = Point.new(@display_x, @display_y)
     targeted_point = Point.new(x, y)
 
     return if initial_point.eql? targeted_point
 
-    delta_x = (targeted_point.x - initial_point.x).abs / nb_steps
-    delta_x = -delta_x if targeted_point.x < initial_point.x
+    nb_steps += 1
 
     linear_interpolant = Point.linear_interpolant(initial_point, targeted_point)
-
-    linear_variation = lambda { |i| initial_point.x + i * delta_x }
+    direction = (targeted_point.x < initial_point.x) ? -1 : 1
+    distance = (initial_point.x - targeted_point.x).abs
+    x_step_variation = Easing.tween(0, distance, nb_steps, easing_function)
+    x_variation = lambda do |i|
+      initial_point.x + direction * x_step_variation.call(i)
+    end
 
     @scroll_function = lambda do |nb_steps_still|
-      return targeted_point if (0 >= nb_steps_still)
+      return targeted_point if (1 >= nb_steps_still)
 
       i = nb_steps - nb_steps_still
-      x = linear_variation.call(i)
+      x = x_variation.call(i)
       y = linear_interpolant.call(x)
 
       Point.new(x % @map.width, y % @map.height)