From a1ab1a0eccc32ec3ed571329dac8d8b251a73cd4 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Thu, 25 Aug 2016 10:25:49 +0100
Subject: [PATCH] Added AdjustSphereSegmentCallback to provide '<' and '>' key
 controls over the azim and elev range of the sphere segment

---
 .../osgspheresegment/osgspheresegment.cpp     | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/examples/osgspheresegment/osgspheresegment.cpp b/examples/osgspheresegment/osgspheresegment.cpp
index b818d8b11..0f0360808 100644
--- a/examples/osgspheresegment/osgspheresegment.cpp
+++ b/examples/osgspheresegment/osgspheresegment.cpp
@@ -354,6 +354,51 @@ osg::Vec3 computeTerrainIntersection(osg::Node* subgraph,float x,float y)
 }
 
 
+class AdjustSphereSegmentCallback : public osgGA::GUIEventHandler
+{
+public:
+    void scaleSphereSegment(osgSim::SphereSegment* ss, float scale)
+    {
+        if (!ss) return;
+
+
+        osg::Vec3 direction_vec;
+        float azRange, elevRange;
+        ss->getArea(direction_vec, azRange, elevRange);
+
+        OSG_NOTICE<<std::endl<<"AdjustSphereSegmentCallback : scaling azRange"<<azRange<<", scale="<<scale<<std::endl;
+        ss->setArea(direction_vec, azRange*scale, elevRange*scale);
+    }
+
+    virtual bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& /*aa*/, osg::Object* object, osg::NodeVisitor* /*nv*/)
+    {
+        if (ea.getHandled()) return false;
+
+        switch(ea.getEventType())
+        {
+            case(osgGA::GUIEventAdapter::KEYDOWN):
+            {
+                if (ea.getKey()=='>')
+                {
+                    scaleSphereSegment(dynamic_cast<osgSim::SphereSegment*>(object), 1.1f);
+                    return true;
+                }
+                else if (ea.getKey()=='<')
+                {
+                    scaleSphereSegment(dynamic_cast<osgSim::SphereSegment*>(object), 1.0f/1.1f);
+                }
+                break;
+            }
+            default:
+                break;
+        }
+        return false;
+    }
+
+
+};
+
+
 //////////////////////////////////////////////////////////////////////////////
 // MAIN SCENE GRAPH BUILDING FUNCTION
 //////////////////////////////////////////////////////////////////////////////
@@ -605,6 +650,8 @@ void build_world(osg::Group *root, unsigned int testCase, bool useOverlay, osgSi
                 ss->getParent(0)->addChild(ss->computeIntersectionSubgraph(terrainToSS, terrainGeode.get()));
             }
 
+            ss->setEventCallback(new AdjustSphereSegmentCallback);
+
         }
     }