[godot] Fix SpineSlotNode Y-down scale regression

Author: badlogic

CHANGELOG.md

@@ -323,6 +323,7 @@
   - Fixed `SpineAnimationTrack` editor preview paths for nested `AnimationPlayer` roots, and prevented inactive tracks from clearing `SpineSprite` preview animations.
   - Fixed GDExtension animation mix editing in the Godot inspector.
   - Fixed `SpineBoneNode` and `SpineSlotNode` transforms when bones use negative scale or shear, and applied `SpineBoneNode` Drive mode before world transforms are computed.
+  - Fixed `SpineSlotNode` and global bone transforms exposing the runtime Y-down coordinate conversion as negative Godot Node2D Y scale.
   - Updated Godot 4.x CI builds to Godot 4.6.2.
   - Fixed Godot 4.6 Windows editor CI builds by installing Direct3D 12 SDK dependencies before building Godot.
   - Fixed Godot 4.6 GDExtension builds with the latest `godot-cpp` by including the required `Ref` support header in `SpineCommon.h`, updated `SpineEventData` for the `EventData.setupPose` API change, and refreshed vendored `spine-cpp` sources during clean setup.

spine-godot/spine_godot/SpineBone.cpp

@@ -190,6 +190,8 @@ Transform2D SpineBone::get_global_transform() {
 	Transform2D local;
 	local[0] = Vector2(applied_pose.getA(), applied_pose.getC());
 	local[1] = Vector2(applied_pose.getB(), applied_pose.getD());
+	// Bone::setYDown(true) is a runtime coordinate conversion for Godot. Don't expose it as an authored Node2D Y scale.
+	if (spine::Bone::isYDown()) local[1] = Vector2(-local[1].x, -local[1].y);
 	local[2] = Vector2(applied_pose.getWorldX(), applied_pose.getWorldY());
 	return get_spine_owner()->get_global_transform() * local;
 }
@@ -205,6 +207,7 @@ void SpineBone::set_global_transform(Transform2D transform) {
 	auto bone = get_spine_object();
 	Transform2D inverse_sprite_transform = get_spine_owner()->get_global_transform().affine_inverse();
 	Transform2D local = inverse_sprite_transform * transform;
+	if (spine::Bone::isYDown()) local[1] = Vector2(-local[1].x, -local[1].y);
 	auto &applied_pose = bone->getAppliedPose();
 	applied_pose.setA(local[0].x);
 	applied_pose.setC(local[0].y);