From 85d2982a295d7ff8bfbf931efb0c27bb84b02c8c Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 6 Sep 2023 13:04:29 +0100
Subject: [PATCH] Added View::share(const View&) method

---
 include/vsg/app/View.h |  5 ++++-
 src/vsg/app/View.cpp   | 18 +++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/include/vsg/app/View.h b/include/vsg/app/View.h
index 72ce9b819..a2393da8d 100644
--- a/include/vsg/app/View.h
+++ b/include/vsg/app/View.h
@@ -26,7 +26,7 @@ namespace vsg
     public:
         View();
 
-        // share the viewID, mask and camera's ViewportState
+        // share the specified view's children, viewID, mask and camera ViewportState
         View(const View& view);
 
         explicit View(ref_ptr<Camera> in_camera, ref_ptr<Node> in_scenegraph = {});
@@ -49,6 +49,9 @@ namespace vsg
         void accept(ConstVisitor& visitor) const override { t_accept(*this, visitor); }
         void accept(RecordTraversal& visitor) const override { t_accept(*this, visitor); }
 
+        /// share the specified view's viewID, mask, camera ViewportState, with this View
+        void share(const View& view);
+
         /// camera controls the viewport state and projection and view matrices
         ref_ptr<Camera> camera;
 
diff --git a/src/vsg/app/View.cpp b/src/vsg/app/View.cpp
index db2044a74..d54373d73 100644
--- a/src/vsg/app/View.cpp
+++ b/src/vsg/app/View.cpp
@@ -76,7 +76,7 @@ View::View(const View& view):
     viewID(sharedViewID(view.viewID)),
     mask(view.mask)
 {
-    if (view.camera)
+    if (view.camera && view.camera->viewportState)
     {
         camera = vsg::Camera::create();
         camera->viewportState = view.camera->viewportState;
@@ -95,3 +95,19 @@ View::~View()
 {
     releaseViewID(viewID);
 }
+
+void View::share(const View& view)
+{
+    if (viewID != view.viewID)
+    {
+        releaseViewID(viewID);
+        const_cast<uint32_t&>(viewID) = sharedViewID(view.viewID);
+    }
+
+    mask = view.mask;
+    if (view.camera && view.camera->viewportState)
+    {
+        if (!camera) camera = vsg::Camera::create();
+        camera->viewportState = view.camera->viewportState;
+    }
+}