Add seamless polygon border line (#4)

Co-authored-by: Hugo Locurcio <[email protected]>

addons/antialiased_line2d/antialiased_line2d.gd

@@ -6,3 +6,14 @@ extends Line2D
 func _ready() -> void:
 	texture = AntialiasedLine2DTexture.texture
 	texture_mode = Line2D.LINE_TEXTURE_TILE
+
+
+static func construct_closed_line(p_polygon: PoolVector2Array) -> PoolVector2Array:
+	var end_point: Vector2 = p_polygon[p_polygon.size() - 1]
+	var distance: float = end_point.distance_to(p_polygon[0]) # distance to start point
+	var bridge_point: Vector2 = end_point.move_toward(p_polygon[0], distance * 0.5)
+	# Close the polygon drawn by the line by adding superimposed bridge points between the start and end points.
+	var polygon_line := p_polygon
+	polygon_line.push_back(bridge_point)
+	polygon_line.insert(0, bridge_point)
+	return polygon_line

addons/antialiased_line2d/antialiased_polygon2d.gd

@@ -16,25 +16,14 @@ var line_2d := Line2D.new()
 func _ready() -> void:
 	line_2d.texture = AntialiasedLine2DTexture.texture
 	line_2d.texture_mode = Line2D.LINE_TEXTURE_TILE
-	# Make the closed polyline look more closed.
-	line_2d.begin_cap_mode = Line2D.LINE_CAP_ROUND
-
-	# Close the polygon drawn by the line by adding the first point to the end.
-	var polygon_line := polygon
 	if polygon.size() >= 1:
-		polygon_line.push_back(polygon[0])
-	line_2d.points = polygon_line
-
+		line_2d.points = AntialiasedLine2D.construct_closed_line(polygon)
 	add_child(line_2d)
 
 
 func _set(property: String, value) -> bool:
 	if property == "polygon":
-		# Close the polygon drawn by the line by adding the first point to the end.
-		var polygon_line := polygon
-		polygon_line.push_back(polygon[0])
-		line_2d.points = polygon_line
-
+		line_2d.points = AntialiasedLine2D.construct_closed_line(polygon)
 	return false
 
 

addons/antialiased_line2d/antialiased_regular_polygon2d.gd

@@ -20,21 +20,13 @@ var line_2d := Line2D.new()
 func _ready() -> void:
 	line_2d.texture = AntialiasedLine2DTexture.texture
 	line_2d.texture_mode = Line2D.LINE_TEXTURE_TILE
-	# Make the closed polyline look more closed.
-	line_2d.begin_cap_mode = Line2D.LINE_CAP_ROUND
-
 	update_points()
-
 	add_child(line_2d)
 
 
 func _set(property: String, value) -> bool:
 	if property == "polygon":
-		# Close the polygon drawn by the line by adding the first point to the end.
-		var polygon_line := polygon
-		polygon_line.push_back(polygon[0])
-		line_2d.points = polygon_line
-
+		line_2d.points = AntialiasedLine2D.construct_closed_line(polygon)
 	return false
 
 
@@ -45,12 +37,8 @@ func update_points() -> void:
 	if not is_equal_approx(angle_degrees, 360.0):
 		points.push_back(Vector2.ZERO)
 	polygon = points
-
 	# Force an update of the Line2D here to prevent it from getting out of sync.
-	# Close the polygon drawn by the line by adding the first point to the end.
-	var polygon_line := polygon
-	polygon_line.push_back(polygon[0])
-	line_2d.points = polygon_line
+	line_2d.points = AntialiasedLine2D.construct_closed_line(polygon)
 
 
 func set_size(p_size: Vector2) -> void: