Snap To Floor improperly offsets node

fix for issue #44282

AABB for collision geometry was being calculated based on parent nodes transform without consideration for collision geometries translation.
Also hopefully clarified logic for selecting starting point for ray cast

(cherry picked from commit 4f171afecc283af407e53fb0553028ff99a9d696)

editor/plugins/spatial_editor_plugin.cpp

@@ -5823,17 +5823,20 @@ void SpatialEditor::snap_selected_nodes_to_floor() {
 			// Priorities for snapping to floor are CollisionShapes, VisualInstances and then origin
 			Set<VisualInstance *> vi = _get_child_nodes<VisualInstance>(sp);
 			Set<CollisionShape *> cs = _get_child_nodes<CollisionShape>(sp);
+			bool found_valid_shape = false;
 
 			if (cs.size()) {
 				AABB aabb;
-				bool found_valid_shape = false;
-				if (cs.front()->get()->get_shape().is_valid()) {
-					aabb = sp->get_global_transform().xform(cs.front()->get()->get_shape()->get_debug_mesh()->get_aabb());
+				Set<CollisionShape *>::Element *I = cs.front();
+				if (I->get()->get_shape().is_valid()) {
+					CollisionShape *collision_shape = cs.front()->get();
+					aabb = collision_shape->get_global_transform().xform(collision_shape->get_shape()->get_debug_mesh()->get_aabb());
 					found_valid_shape = true;
 				}
-				for (Set<CollisionShape *>::Element *I = cs.front(); I; I = I->next()) {
-					if (I->get()->get_shape().is_valid()) {
-						aabb.merge_with(sp->get_global_transform().xform(I->get()->get_shape()->get_debug_mesh()->get_aabb()));
+				for (I = I->next(); I; I = I->next()) {
+					CollisionShape *col_shape = I->get();
+					if (col_shape->get_shape().is_valid()) {
+						aabb.merge_with(col_shape->get_global_transform().xform(col_shape->get_shape()->get_debug_mesh()->get_aabb()));
 						found_valid_shape = true;
 					}
 				}
@@ -5841,10 +5844,9 @@ void SpatialEditor::snap_selected_nodes_to_floor() {
 					Vector3 size = aabb.size * Vector3(0.5, 0.0, 0.5);
 					from = aabb.position + size;
 					position_offset.y = from.y - sp->get_global_transform().origin.y;
-				} else {
-					from = sp->get_global_transform().origin;
 				}
-			} else if (vi.size()) {
+			}
+			if (!found_valid_shape && vi.size()) {
 				AABB aabb = vi.front()->get()->get_transformed_aabb();
 				for (Set<VisualInstance *>::Element *I = vi.front(); I; I = I->next()) {
 					aabb.merge_with(I->get()->get_transformed_aabb());
@@ -5852,7 +5854,7 @@ void SpatialEditor::snap_selected_nodes_to_floor() {
 				Vector3 size = aabb.size * Vector3(0.5, 0.0, 0.5);
 				from = aabb.position + size;
 				position_offset.y = from.y - sp->get_global_transform().origin.y;
-			} else {
+			} else if (!found_valid_shape) {
 				from = sp->get_global_transform().origin;
 			}