Refactor IsometricCamera3D vol. 2

source/match/IsometricCamera3D.gd

@@ -13,17 +13,16 @@ const EXPECTED_PROJECTION = PROJECTION_ORTHOGONAL
 @export var movement_speed = 1.1
 @export var bounding_planes: Array[Plane] = []
 @export_group("Rotation")
-@export var mouse_rotation_speed = 0.005
+@export var mouse_rotation_speed = 0.005  # [rad/px]
 @export var arrowkey_rotation_speed = 2  # [rad/s]
 @export var default_y_rotation_degrees = 0.0
 @export var reference_plane_for_rotation = Plane(Vector3.UP, 0.0)
 @export_group("View")
 @export var visible_height_min = -10
 @export var visible_height_max = 10
 
-var _pivot_point_2d = null
-var _pivot_point_3d = null
-var _camera_point_3d = null
+var _mouse_pos_when_rotation_started = null
+var _camera_global_pos_when_rotation_started = null
 
 
 func _ready():
@@ -79,8 +78,10 @@ func _try_handling_movement(delta: float) -> bool:
 		* Vector2(movement_speed, movement_speed * 2.0)
 		* size
 	)
-	var camera_move_vector = Vector3(scaled_screen_move_vector.x, 0, scaled_screen_move_vector.y)
-	camera_move_vector = camera_move_vector.rotated(Vector3(0, 1, 0), rotation.y)
+	var camera_move_vector = (
+		Vector3(scaled_screen_move_vector.x, 0, scaled_screen_move_vector.y)
+		. rotated(Vector3(0, 1, 0), rotation.y)
+	)
 	global_translate(camera_move_vector)
 	_align_position_to_bounding_planes()
 	return true
@@ -135,7 +136,7 @@ func _try_handling_arrowkey_rotation(delta: float):
 		* arrowkey_rotation_speed
 	)
 	if not is_zero_approx(angle_radians):
-		_rotate_by(angle_radians)
+		_rotate_from_reference_position_by(global_position, angle_radians)
 
 
 func _try_handling_mouse_rotation(event: InputEvent):
@@ -146,19 +147,21 @@ func _try_handling_mouse_rotation(event: InputEvent):
 			_start_rotation(event)
 		elif not event.is_pressed() and event.button_index == MOUSE_BUTTON_MIDDLE:
 			_stop_rotation()
-	elif event is InputEventMouseMotion:
+	elif event is InputEventMouseMotion and _is_rotating():
 		var mouse_pos = event.position
-		if _is_rotating():
-			_rotate(mouse_pos)
+		var angle_radians = (
+			(mouse_pos.x - _mouse_pos_when_rotation_started.x) * mouse_rotation_speed
+		)
+		_rotate_from_reference_position_by(_camera_global_pos_when_rotation_started, angle_radians)
 
 
 func _reset_rotation():
-	var pivot_point_3d = _calculate_pivot_point_3d()
-	if pivot_point_3d == null:
+	var pivot_point = _calculate_pivot_point()
+	if pivot_point == null:
 		return
 	var camera_point_3d = global_transform.origin
 	var camera_point_2d = Vector2(camera_point_3d.x, camera_point_3d.z)
-	var pivot_point_2d = Vector2(pivot_point_3d.x, pivot_point_3d.z)
+	var pivot_point_2d = Vector2(pivot_point.x, pivot_point.z)
 	var pivot_to_camera_distance_2d = camera_point_2d.distance_to(pivot_point_2d)
 	var new_camera_point_2d = (
 		pivot_point_2d
@@ -170,54 +173,38 @@ func _reset_rotation():
 	global_transform.origin = Vector3(
 		new_camera_point_2d.x, camera_point_3d.y, new_camera_point_2d.y
 	)
-	global_transform = global_transform.looking_at(pivot_point_3d, Vector3(0, 1, 0))
+	global_transform = global_transform.looking_at(pivot_point, Vector3(0, 1, 0))
 
 
 func _start_rotation(event: InputEvent):
-	_pivot_point_3d = _calculate_pivot_point_3d()
-	if _pivot_point_3d != null:
-		_pivot_point_2d = event.position
-		_camera_point_3d = global_transform.origin
+	_mouse_pos_when_rotation_started = event.position
+	_camera_global_pos_when_rotation_started = global_transform.origin
 
 
 func _stop_rotation():
-	_pivot_point_2d = null
-
-
-func _rotate(mouse_pos: Vector2):
-	var strength = mouse_pos.x - _pivot_point_2d.x
-	var camera_point_2d = Vector2(_camera_point_3d.x, _camera_point_3d.z)
-	var pivot_point_2d = Vector2(_pivot_point_3d.x, _pivot_point_3d.z)
-	var diff_vec = camera_point_2d - pivot_point_2d
-	var rotated_diff_vec = diff_vec.rotated(strength * mouse_rotation_speed)
-	var new_camera_point_2d = pivot_point_2d + rotated_diff_vec
-	global_transform.origin = Vector3(
-		new_camera_point_2d.x, _camera_point_3d.y, new_camera_point_2d.y
-	)
-	global_transform = global_transform.looking_at(_pivot_point_3d, Vector3(0, 1, 0))
+	_mouse_pos_when_rotation_started = null
 
 
-func _rotate_by(angle_radians: float):
-	var pivot_point_3d = _calculate_pivot_point_3d()
-	if pivot_point_3d == null:
+func _rotate_from_reference_position_by(reference_position: Vector3, angle_radians: float):
+	var pivot_point = _calculate_pivot_point()
+	if pivot_point == null:
 		return
-	var camera_point_3d = global_transform.origin
-	var camera_point_2d = Vector2(camera_point_3d.x, camera_point_3d.z)
-	var pivot_point_2d = Vector2(pivot_point_3d.x, pivot_point_3d.z)
-	var diff_vec = camera_point_2d - pivot_point_2d
-	var rotated_diff_vec = diff_vec.rotated(angle_radians)
-	var new_camera_point_2d = pivot_point_2d + rotated_diff_vec
-	global_transform.origin = Vector3(
-		new_camera_point_2d.x, camera_point_3d.y, new_camera_point_2d.y
+
+	var diff_vec_yless = reference_position * Vector3(1, 0, 1) - pivot_point * Vector3(1, 0, 1)
+	var rotated_diff_vec_yless = diff_vec_yless.rotated(-Vector3.UP, angle_radians)
+	var rotated_reference_position = (
+		pivot_point
+		+ Vector3(rotated_diff_vec_yless.x, reference_position.y, rotated_diff_vec_yless.z)
 	)
-	global_transform = global_transform.looking_at(pivot_point_3d, Vector3(0, 1, 0))
+	global_position = rotated_reference_position
+	global_transform = global_transform.looking_at(pivot_point, Vector3.UP)
 
 
 func _is_rotating() -> bool:
-	return _pivot_point_2d != null
+	return _mouse_pos_when_rotation_started != null
 
 
-func _calculate_pivot_point_3d() -> Vector3:
+func _calculate_pivot_point() -> Vector3:
 	var screen_center_pos_2d = get_viewport().size / 2.0
 	return get_ray_intersection_with_plane(screen_center_pos_2d, reference_plane_for_rotation)
 
@@ -261,7 +248,7 @@ func _align_camera_far_to_size(a_size: float):
 
 
 func _align_position_to_bounding_planes():
-	var pivot_point = _calculate_pivot_point_3d()
+	var pivot_point = _calculate_pivot_point()
 	var aligned_pivot_point = _clamp_position_to_bounding_planes(pivot_point)
 	var diff = aligned_pivot_point - pivot_point
 	global_transform.origin += diff