refactor: move effect logic into one function

This makes it much easier to support multiple effects.

Author: danielzting

levels/bogo_sort.gd

@@ -20,5 +20,5 @@ func next():
     if array.is_sorted():
         emit_signal("done")
 
-func emphasized(i):
-    return false
+func get_effect(i):
+    return EFFECTS.NONE

levels/bubble_sort.gd

@@ -10,7 +10,7 @@ finished. Though simple to understand, bubble sort is hopelessly
 inefficient on all but the smallest of arrays.
 """
 const CONTROLS = """
-If the two highlighted elements are out of order, hit LEFT ARROW to SWAP
+If the two highlighted elements are out of order, hit LEFT ARROW to swap
 them. Otherwise, hit RIGHT ARROW to continue.
 """
 
@@ -37,5 +37,7 @@ func next():
         _index = 0
         _swapped = false
 
-func emphasized(i):
-    return i == _index or i == _index + 1
+func get_effect(i):
+    if i == _index or i == _index + 1:
+        return EFFECTS.HIGHLIGHTED
+    return EFFECTS.NONE

levels/comparison_sort.gd

@@ -4,7 +4,20 @@ extends Node
 signal done
 signal mistake
 
-enum ACTIONS {SWAP, NO_SWAP}
+enum ACTIONS {
+    SWAP,
+    NO_SWAP,
+
+    LEFT,
+    RIGHT,
+}
+
+const EFFECTS = {
+    "NONE": GlobalTheme.GREEN,
+    "HIGHLIGHTED": GlobalTheme.ORANGE,
+    "DIMMED": GlobalTheme.DARK_GREEN,
+    "WUT": 0,
+}
 
 const DISABLE_TIME = 1.0
 
@@ -25,12 +38,13 @@ func _input(event):
     """Pass input events for checking and take appropriate action."""
     if not active:
         return
+
     for action in ACTIONS:
         if event.is_action_pressed(action):
             if check(ACTIONS[action]):
-                next()
-            else:
-                emit_signal("mistake")
+                return next()
+    if event.is_pressed():
+        emit_signal("mistake")
 
 func check(action):
     """Determine if the given action enum value is correct."""
@@ -40,10 +54,6 @@ func next():
     """Advance the state by one step and signal done if completed."""
     push_error("NotImplementedError")
 
-func emphasized(i):
-    """Return whether the given index should be highlighted."""
-    push_error("NotImplementedError")
-
 func _on_ComparisonSort_mistake():
     """Disable the controls for one second."""
     active = false

levels/insertion_sort.gd

@@ -10,13 +10,13 @@ one of the faster quadratic algorithms. It is often used to sort smaller
 subarrays in hybrid sorting algorithms.
 """
 const CONTROLS = """
-Hit LEFT ARROW to SWAP the two highlighted elements as long as they are
+Hit LEFT ARROW to swap the two highlighted elements as long as they are
 out of order. When this is no longer the case, hit RIGHT ARROW to
 advance.
 """
 
-var _end = 1
-var _index = _end
+var _end = 1 # Size of the sorted subarray
+var _index = 1 # Position of element currently being inserted
 
 func _init(array).(array):
     pass
@@ -36,11 +36,13 @@ func next():
     else:
         _grow()
 
+func get_effect(i):
+    if i == _index or i == _index - 1:
+        return EFFECTS.HIGHLIGHTED
+    return EFFECTS.NONE
+
 func _grow():
     _end += 1
     if _end == array.size:
         emit_signal("done")
     _index = _end
-
-func emphasized(i):
-    return i == _index or i == _index - 1

levels/selection_sort.gd

@@ -15,8 +15,8 @@ smaller than the left highlighted element, then hit LEFT ARROW to swap
 the new smallest into place and keep going.
 """
 
-var _base = 0
-var _index = _base + 1
+var _base = 0 # Size of sorted subarray
+var _index = 1 # Index of tentative new smallest
 
 func _init(array).(array):
     pass
@@ -37,5 +37,7 @@ func next():
     if _base == array.size - 1:
         emit_signal("done")
 
-func emphasized(i):
-    return i == _index or i == _base
+func get_effect(i):
+    if i == _index or i == _base:
+        return EFFECTS.HIGHLIGHTED
+    return EFFECTS.NONE

project.godot

@@ -40,6 +40,11 @@ _global_script_classes=[ {
 "path": "res://levels/insertion_sort.gd"
 }, {
 "base": "ComparisonSort",
+"class": "MergeSort",
+"language": "GDScript",
+"path": "res://levels/merge_sort.gd"
+}, {
+"base": "ComparisonSort",
 "class": "SelectionSort",
 "language": "GDScript",
 "path": "res://levels/selection_sort.gd"
@@ -51,6 +56,7 @@ _global_script_class_icons={
 "BubbleSort": "",
 "ComparisonSort": "",
 "InsertionSort": "",
+"MergeSort": "",
 "SelectionSort": ""
 }
 
@@ -127,6 +133,16 @@ NO_SWAP={
 "events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777233,"unicode":0,"echo":false,"script":null)
  ]
 }
+LEFT={
+"deadzone": 0.5,
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777231,"unicode":0,"echo":false,"script":null)
+ ]
+}
+RIGHT={
+"deadzone": 0.5,
+"events": [ Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"alt":false,"shift":false,"control":false,"meta":false,"command":false,"pressed":false,"scancode":16777233,"unicode":0,"echo":false,"script":null)
+ ]
+}
 
 [rendering]
 

scripts/levels.gd

@@ -4,6 +4,7 @@ var levels = [
     BubbleSort,
     InsertionSort,
     SelectionSort,
+    MergeSort,
 ]
 var level: ComparisonSort
 
@@ -19,9 +20,14 @@ func _ready():
         # Autofocus last played level
         if GlobalScene.get_param("level") == level:
             button.grab_focus()
-    # If no last played level, autofocus first
+    var top_button = $LevelsBorder/Levels.get_children()[0]
+    var bottom_button = $LevelsBorder/Levels.get_children()[-1]
+    # Allow looping from ends of list
+    top_button.focus_neighbour_top = bottom_button.get_path()
+    bottom_button.focus_neighbour_bottom = top_button.get_path()
+    # If no last played level, autofocus first level
     if GlobalScene.get_param("level") == null:
-        $LevelsBorder/Levels.get_child(0).grab_focus()
+        top_button.grab_focus()
 
 func _on_Button_focus_changed():
     """Initialize the preview section."""

scripts/theme.gd

@@ -5,5 +5,6 @@ Global constants relating to the GUI.
 extends Node
 
 const GREEN = Color(0.2, 1, 0.2)
+const DARK_GREEN = Color(0.2, 1, 0.2, 0.5)
 const ORANGE = Color(1, 0.69, 0)
 const RED = Color(1, 0, 0)

views/array_view.gd

@@ -24,7 +24,7 @@ func _process(delta):
     """Update heights of rectangles based on array values."""
     for i in range(level.array.size):
         rects[i].rect_scale.y = -1 # XXX: Override parent Control scale
-        rects[i].color = GlobalTheme.ORANGE if level.emphasized(i) else GlobalTheme.GREEN
+        rects[i].color = level.get_effect(i)
         rects[i].rect_size.y = rect_size.y * level.array.get(i) / level.array.size
 
 func _on_Level_mistake():