Set up framework for more advance pickup behaviours.

scripts/pickups/pickup_behavior_controller.gd

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+class_name PickupBehaviorController extends Area2D
+
+## Controls visual movement (bob, shake) and drift of a pickup.
+## Attach to the root Area2D node of your pickup scene.
+
+@export var behavior: PickupBehavior
+@export var drift_behavior: PickupDriftBehavior
+
+
+var _icon_node: TextureRect
+var _spawn_position: Vector2 = Vector2.ZERO
+
+
+func _ready() -> void:
+    # Find the runtime-added icon node.
+    for child in get_children():
+        if child is TextureRect:
+            _icon_node = child as TextureRect
+            break
+    # Capture the initial spawn position.
+    _spawn_position = global_position
+
+    if behavior != null:
+        behavior.start()
+
+
+func _process(delta: float) -> void:
+    if behavior == null or drift_behavior == null:
+        return
+
+    var alpha: float = behavior.process(delta)
+
+    if _icon_node != null:
+        _icon_node.visible = alpha > 0.01
+        if behavior != null and behavior.fade_in_duration > 0 and _icon_node is CanvasItem:
+            _icon_node.modulate.a = alpha
+
+    var offset := _compute_animation_offset()
+    var drift_offset := _compute_drift_offset()
+
+    position = _spawn_position + Vector2(drift_offset.x, drift_offset.y)
+
+    if _icon_node != null:
+        _icon_node.position = offset
+
+
+func _compute_animation_offset() -> Vector2:
+    # Returns the bob + shake offset applied to the icon node.
+    var result := Vector2.ZERO
+
+    if behavior == null:
+        return result
+
+    # Bob (vertical oscillation).
+    if behavior.bob_enabled:
+        var bob_angle := _elapsed_time() * TAU * behavior.bob_frequency
+        result.y += sin(bob_angle) * behavior.bob_amplitude
+
+    # Shake (subtle jitter).
+    if behavior.shake_enabled:
+        var shake_angle := _elapsed_time() * TAU * behavior.shake_frequency
+        result.x += sin(shake_angle) * behavior.shake_amplitude
+
+    return result
+
+
+func _compute_drift_offset() -> Vector2:
+    # Returns the global drift position offset from initial spawn position.
+    if drift_behavior == null:
+        return Vector2.ZERO
+
+    match drift_behavior.drift_type:
+        PickupDriftBehavior.DriftType.STATIONARY:
+            return Vector2.ZERO
+
+        PickupDriftBehavior.DriftType.SINE_WAVE:
+            var t := _elapsed_time() * drift_behavior.wave_frequency
+            var travel_speed: float = drift_behavior.drift_speed
+            if drift_behavior.reverse_direction:
+                travel_speed *= -1.0
+
+            var offset := Vector2.ZERO
+            if drift_behavior.drift_along_x:
+                # Travels along X; waves on Y.
+                offset.x = travel_speed * _elapsed_time()
+                offset.y = sin(t + drift_behavior.phase_offset) * drift_behavior.wave_amplitude
+            else:
+                # Travels along Y; waves on X.
+                offset.y = travel_speed * _elapsed_time()
+                offset.x = sin(t + drift_behavior.phase_offset) * drift_behavior.wave_amplitude
+            return offset
+
+        PickupDriftBehavior.DriftType.LEAF_FALL:
+            var leaf_t := _elapsed_time() * drift_behavior.wave_frequency
+            var travel_speed: float = drift_behavior.fall_speed
+            if drift_behavior.reverse_direction:
+                travel_speed *= -1.0
+
+            var offset := Vector2.ZERO
+            if drift_behavior.drift_along_x:
+                # Travels along X; waves on Y.
+                offset.x = travel_speed * _elapsed_time()
+                offset.y = sin(leaf_t + drift_behavior.phase_offset) * drift_behavior.wave_amplitude
+            else:
+                # Travels along Y; waves on X.
+                offset.y = travel_speed * _elapsed_time()
+                offset.x = sin(leaf_t + drift_behavior.phase_offset) * drift_behavior.wave_amplitude
+            return offset
+
+        PickupDriftBehavior.DriftType.DIAGONAL:
+            var dir: float = 1.0 if drift_behavior.diagonal_forward else -1.0
+            if drift_behavior.reverse_direction:
+                dir *= -1.0
+
+            var offset := Vector2.ZERO
+            if drift_behavior.drift_along_x:
+                # Travels along X; secondary on Y.
+                offset.x = dir * drift_behavior.drift_speed * _elapsed_time()
+                offset.y = dir * (drift_behavior.drift_speed * 0.5) * _elapsed_time()
+            else:
+                # Travels along Y; secondary on X.
+                offset.y = dir * drift_behavior.drift_speed * _elapsed_time()
+                offset.x = dir * (drift_behavior.drift_speed * 0.5) * _elapsed_time()
+            return offset
+
+    return Vector2.ZERO
+
+
+func _elapsed_time() -> float:
+    if behavior == null:
+        return 0.0
+    return behavior._elapsed

scripts/pickups/pickup_behavior_controller.gd.uid

@@ -0,0 +1 @@
+uid://c4a7husvaq2eo