road simplification via Ramer–Douglas–Peucker

2 files changed, 50 insertions, 1 deletions

diff --git a/Scripts/Road.gd b/Scripts/Road.gd
new file mode 100644
index 0000000..e0b69a1
--- /dev/null
+++ b/Scripts/Road.gd
@@ -0,0 +1,48 @@
+extends Line2D
+
+var epsilon = 20
+
+# Called when the node enters the scene tree for the first time.
+func _ready():
+	pass # Replace with function body.
+
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta):
+	pass
+
+func simplify():
+	points = simplify_rec(points, 5)
+
+func simplify_rec(pointArray: PackedVector2Array, epsilon: float):
+	var dmax = 0
+	var index = -1
+	if pointArray.size() < 3:
+		return pointArray
+	var end = pointArray.size() - 1
+	for i in range(1, end-1):
+		var d = find_perpendicular_distance(pointArray[i], pointArray[0], pointArray[end])
+		if d > dmax:
+			index = i
+			dmax = d
+	
+	if dmax > epsilon:
+		var recResults1 = simplify_rec(pointArray.slice(0, index), epsilon)
+		var recResults2 = simplify_rec(pointArray.slice(index, end), epsilon)
+		recResults1.append_array(recResults2)
+		return recResults1
+	else:
+		return [pointArray[0], pointArray[end]]
+
+func find_perpendicular_distance(p: Vector2, p1: Vector2, p2: Vector2):
+	var result
+	var slope
+	var intercept
+	if p1.x == p2.x:
+		result = p.x - p1.x
+	else:
+		slope = (p2.y - p1.y) / (p2.x - p1.x)
+		intercept = p1.y - (slope * p1.x)
+		result = abs(slope * p.x - p.y + intercept) / sqrt(pow(slope, 2) + 1)
+	
+	return result
diff --git a/Scripts/drawing.gd b/Scripts/drawing.gd
index 61896f9..c45196b 100644
--- a/Scripts/drawing.gd
+++ b/Scripts/drawing.gd
@@ -2,7 +2,7 @@ extends Node
 
 var drawing = false
 
-@onready var line: Line2D = $TrackLine
+@onready var line = $Road
 @onready var path: Path2D = $TrackPath
 
 func _ready():
@@ -16,6 +16,7 @@ func start_drawing():
 
 func _end_drawing():
 	drawing = false
+	line.simplify()
 	owner.set_driving(true)