Godot Version
4.7
Question
I’m making an ice hockey rink where the edges are walls so play can happen within.
I’m using a `CollisionPolygon2D` with Build Mode set to `Segments` so that it’s not solid and things can be inside the what is in effect a rounded rectangle.
I’m creating the polygon with script so the length and width of the rectangle can be configured.
My problem is that it seems the rounded corners are “jagged” so my little puck doesn’t slide along it, it bounces when it hits the curve.
Here’s a video clip of what happens.
The corner creation code looks like this,
# Top left rounded corner.
var center = Vector2(corner_radius, corner_radius)
for angle in range(270, 180, -1):
var rad = deg_to_rad(angle)
polygon.append(center + Vector2(cos(rad), sin(rad)) * corner_radius)
The polygon is set _collision_polygon_2d.polygon = polygon in the end.
Is there a better way to get smooth rounded edges so things can slide all along them?
Here’s the full function that generates the collision polygon.
func _generate_collision_polygon() -> void:
var corner_radius = rules.corner_radius * pixels_per_meter
var height = rules.height * pixels_per_meter
var width = rules.width * pixels_per_meter
var polygon = PackedVector2Array()
# Top left rounded corner.
var center = Vector2(corner_radius, corner_radius)
for angle in range(270, 180, -1):
var rad = deg_to_rad(angle)
polygon.append(center + Vector2(cos(rad), sin(rad)) * corner_radius)
# Left edge (top to bottom).
polygon.append(Vector2(0, corner_radius))
polygon.append(Vector2(0, height - corner_radius))
# Bottom-left arc (clockwise: 90° to 180°).
center = Vector2(corner_radius, height - corner_radius)
for angle in range(180, 90, -1):
var rad = deg_to_rad(angle)
polygon.append(center + Vector2(cos(rad), sin(rad)) * corner_radius)
# Bottom edge (right to left).
polygon.append(Vector2(corner_radius, height))
polygon.append(Vector2(width - corner_radius, height))
# Bottom-right arc (clockwise: 0° to 90°).
center = Vector2(width - corner_radius, height - corner_radius)
for angle in range(90, 0, -1):
var rad = deg_to_rad(angle)
polygon.append(center + Vector2(cos(rad), sin(rad)) * corner_radius)
# Right edge (bottom to top).
polygon.append(Vector2(width, height - corner_radius))
polygon.append(Vector2(width, corner_radius))
# Top-right arc (clockwise: 270° to 360°).
center = Vector2(width - corner_radius, corner_radius)
for angle in range(360, 270, -1):
var rad = deg_to_rad(angle)
polygon.append(center + Vector2(cos(rad), sin(rad)) * corner_radius)
# Top edge (left to right).
polygon.append(Vector2(width - corner_radius, 0))
polygon.append(Vector2(corner_radius, 0))
# Close the polygon.
polygon.append(polygon[0])
_collision_polygon_2d.polygon = polygon
_polygon_2d.polygon = polygon
_polygon_2d.color = Color(0.75, 0.9, 0.9, 1.0)
