feat(smooth_movement): 添加 smooth_movement 类

smooth_movement 可用于维护平滑移动的坐标。

scripts/smooth_movement/smooth_movement.gd

@@ -0,0 +1,45 @@
+class_name SmoothMovement extends Timer
+
+var last_position := Vector2.ZERO
+var target_position := Vector2.ZERO
+
+
+enum SmoothType {
+    LINEAR,
+    QUAD_FADE_OUT,
+    SMOOTH_STEP,
+}
+
+@export var smooth_type := SmoothType.LINEAR
+
+
+static func smooth_step(v1: Vector2, v2: Vector2, t: float) -> Vector2:
+    var t1 := t * t
+    var t2 := 1.0 - (1.0 - t) * (1.0 - t)
+    return v1.lerp(v2, lerpf(t1, t2, t))
+
+static func quad_fade_out(v1: Vector2, v2: Vector2, t: float) -> Vector2:
+    return v1.lerp(v2, 1.0 - (1.0 - t) * (1.0 - t))
+
+
+func set_position(position: Vector2):
+    self.last_position = position
+    self.target_position = position
+
+
+func move_to(target_pos: Vector2, time: float) -> void:
+    self.last_position = self.target_position
+    self.target_position = target_pos
+    self.start(time)
+
+func get_position() -> Vector2:
+    var t := 1.0 - self.time_left / self.wait_time
+    match self.smooth_type:
+        SmoothType.LINEAR:
+            return self.last_position.lerp(self.target_position, t)
+        SmoothType.QUAD_FADE_OUT:
+            return SmoothMovement.quad_fade_out(self.last_position, self.target_position, t)
+        SmoothType.SMOOTH_STEP:
+            return SmoothMovement.smooth_step(self.last_position, self.target_position, t)
+    return Vector2.ZERO
+

scripts/smooth_movement/smooth_movement.tscn

@@ -0,0 +1,7 @@
+[gd_scene load_steps=2 format=3 uid="uid://fxcs5dmb21q2"]
+
+[ext_resource type="Script" path="res://scripts/smooth_movement/smooth_movement.gd" id="1_88rjn"]
+
+[node name="SmoothMovement" type="Timer"]
+one_shot = true
+script = ExtResource("1_88rjn")