From 1bc204a87f19a9368bfe68705375da891ff45839 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 19 Nov 2009 11:21:05 +0000
Subject: [PATCH] From J.P. Delport, "simple addition to make the scroll wheel
 work in the example."

---
 examples/osgviewerWX/osgviewerWX.cpp | 13 +++++++++++++
 examples/osgviewerWX/osgviewerWX.h   |  1 +
 2 files changed, 14 insertions(+)

diff --git a/examples/osgviewerWX/osgviewerWX.cpp b/examples/osgviewerWX/osgviewerWX.cpp
index 518fbc96a..0a7ac616f 100644
--- a/examples/osgviewerWX/osgviewerWX.cpp
+++ b/examples/osgviewerWX/osgviewerWX.cpp
@@ -127,6 +127,7 @@ BEGIN_EVENT_TABLE(OSGCanvas, wxGLCanvas)
     EVT_MIDDLE_UP           (OSGCanvas::OnMouseUp)
     EVT_RIGHT_UP            (OSGCanvas::OnMouseUp)
     EVT_MOTION              (OSGCanvas::OnMouseMotion)
+    EVT_MOUSEWHEEL          (OSGCanvas::OnMouseWheel)
 END_EVENT_TABLE()
 
 OSGCanvas::OSGCanvas(wxWindow *parent, wxWindowID id,
@@ -229,6 +230,18 @@ void OSGCanvas::OnMouseMotion(wxMouseEvent &event)
         _graphics_window->getEventQueue()->mouseMotion(event.GetX(), event.GetY());
 }
 
+void OSGCanvas::OnMouseWheel(wxMouseEvent &event)
+{
+    int delta = event.GetWheelRotation() / event.GetWheelDelta() * event.GetLinesPerAction();
+
+    if (_graphics_window.valid()) {
+        _graphics_window->getEventQueue()->mouseScroll(
+            delta>0 ? 
+            osgGA::GUIEventAdapter::SCROLL_UP : 
+            osgGA::GUIEventAdapter::SCROLL_DOWN);
+    }
+}
+
 void OSGCanvas::UseCursor(bool value)
 {
     if (value)
diff --git a/examples/osgviewerWX/osgviewerWX.h b/examples/osgviewerWX/osgviewerWX.h
index 53c06ff90..a79368c9e 100644
--- a/examples/osgviewerWX/osgviewerWX.h
+++ b/examples/osgviewerWX/osgviewerWX.h
@@ -34,6 +34,7 @@ public:
     void OnMouseDown(wxMouseEvent &event);
     void OnMouseUp(wxMouseEvent &event);
     void OnMouseMotion(wxMouseEvent &event);
+    void OnMouseWheel(wxMouseEvent &event);
 
     void UseCursor(bool value);