Brush stroke smoothing using cubic bezier curves

It feels so much better!
mbrlabs · Aug 29, 2024 · e5e7c26 · e5e7c26
1 parent bb0ece2
commit e5e7c26
Show file tree

Hide file tree

Showing 3 changed files with 28 additions and 4 deletions.
diff --git a/lorien/BrushStroke/BrushStrokeOptimizer.gd b/lorien/BrushStroke/BrushStrokeOptimizer.gd
@@ -1,8 +1,8 @@
 class_name BrushStrokeOptimizer
 
 # -------------------------------------------------------------------------------------------------
-const ANGLE_THRESHOLD := 1.0
-const DISTANCE_THRESHOLD := 2.0
+const ANGLE_THRESHOLD := 0.5
+const DISTANCE_THRESHOLD := 1.0
 
 # -------------------------------------------------------------------------------------------------
 var points_removed := 0

diff --git a/lorien/InfiniteCanvas/Tools/BrushTool.gd b/lorien/InfiniteCanvas/Tools/BrushTool.gd
@@ -39,15 +39,24 @@ func _process(delta: float) -> void:
  if performing_stroke:
  var pos := _cursor.global_position
 
- # Basic smoothing
+ # Smoothing
  var diff := pos.distance_squared_to(_last_accepted_position)
  if diff <= MOVEMENT_THRESHOLD || _current_pressure <= MIN_PRESSURE:
  return
-
+
+ var points := get_current_brush_stroke().points
+ if points.size() > 3:
+ var p3 := points[-3]
+ var p2 := points[-2]
+ var p1 := points[-1]
+ # TODO: expose the smoothing factor in the settings
+ pos = Utils.cubic_bezier(p3, p2, p1, pos, 0.75)
+
  var sensitivity: float = Settings.get_general_value(
  Settings.GENERAL_PRESSURE_SENSITIVITY, Config.DEFAULT_PRESSURE_SENSITIVITY
  )
 
+ # Pressure
  var point_pressure := pressure_curve.sample(_current_pressure) * sensitivity
  if _first_point:
  point_pressure *= 1.4

diff --git a/lorien/Misc/Utils.gd b/lorien/Misc/Utils.gd
@@ -85,3 +85,18 @@ func translate_action(action_name: String) -> String:
 # Does an _exact_ match for the given key stroke.
 func event_pressed_bug_workaround(action_name: String, event: InputEvent) -> bool:
  return InputMap.action_has_event(action_name, event) && event.is_pressed() && !event.is_echo()
+
+# -------------------------------------------------------------------------------------------------
+func cubic_bezier(p0: Vector2, p1: Vector2, p2: Vector2, p3: Vector2, t: float) -> Vector2:
+ var q0 := p0.lerp(p1, t)
+ var q1 := p1.lerp(p2, t)
+ var q2 := p2.lerp(p3, t)
+ var r0 := q0.lerp(q1, t)
+ var r1 := q1.lerp(q2, t)
+ return r0.lerp(r1, t)
+
+# -------------------------------------------------------------------------------------------------
+func quadratic_bezier(p0: Vector2, p1: Vector2, p2: Vector2, t: float) -> Vector2:
+ var q0 := p0.lerp(p1, t)
+ var q1 := p1.lerp(p2, t)
+ return q0.lerp(q1, t)