comment rolling fiend

objects/enemy/rolling_fiend.gd

@@ -1,23 +1,30 @@
 extends "res://objects/enemy/enemy.gd"
 
+## the floor directions a fiend can be attached to
 const DIRS = [Vector2.DOWN, Vector2.RIGHT, Vector2.UP, Vector2.LEFT]
 
 export var move_speed: float = 50.0
 export var clockwise: bool = false
 
+## keep options for shape query around because they will mostly stay the same
 onready var floor_test = Physics2DShapeQueryParameters.new()
 onready var test_shape = $FloorTestShape
 
+## index of the current floor direction
 var floor_direction: int = 0
+## builds up movement so that fractional movement carries on
 var movement_accumulator: float = 0.0
 
 func _ready():
 	# scale animation to move speed
 	$AnimatedSprite.speed_scale = inverse_lerp(0.0, 50.0, move_speed)
+	# flip if going backwards
 	if clockwise:
 		$AnimatedSprite.flip_h = true
+	# fill in shape query parameters that stay the same
 	floor_test.set_shape(test_shape.shape)
 	floor_test.collision_layer = 1
+	# loop through possible directions to find which one should start on
 	for i in DIRS.size():
 		if is_on_surface(DIRS[i]):
 			floor_direction = i
@@ -26,18 +33,32 @@ func _ready():
 	move_speed *= Game.enemy_speed_factor
 
 func _physics_process(delta):
+	# add to accumulator
 	movement_accumulator += move_speed * delta
+	# move one pixel at a time until out of integer movment
 	while movement_accumulator >= 1.0:
+		# check next direction for wall if clockwise, else previous
 		var offset = 1 if clockwise else -1
+		# movement dir should be the next direction from the floor direction
 		var move_dir = posmod(floor_direction + offset, DIRS.size())
+		# check if gone off edge
 		if !is_on_surface(DIRS[floor_direction]):
+			# change to next floor direction
 			floor_direction = posmod(floor_direction - offset, DIRS.size())
+		# check if collided with wall
 		elif is_on_surface(DIRS[move_dir]):
+			# new floor direction is where wall is
 			floor_direction = move_dir
+		# move along new floor direction
 		position += DIRS[posmod(floor_direction + offset, DIRS.size())]
+		# 1 pixel of movement spent from accumulator
 		movement_accumulator -= 1.0
 
+## tests if there is a floor 1 pixel in the direction tested
 func is_on_surface(dir):
+	# get the physics space state
 	var space_state = get_world_2d().direct_space_state
+	# set position to test box at, moved 1 pixel in the direction tested
 	floor_test.transform = test_shape.global_transform.translated(dir)
-	return space_state.collide_shape(floor_test, 1).size() > 0
+	# collide_shape returns array of collisions, if not empy there is a floor there
+	return not space_state.collide_shape(floor_test, 1).empty()