Added support for "pixel-size-on-screen" rendering to feature model /…

… tiled feature model.

src/osgEarth/FeatureDisplayLayout

@@ -116,6 +116,27 @@ namespace osgEarth
          optional<float>& minRange() { return _minRange; }
          const optional<float>& minRange() const { return _minRange; }
 
+        /**
+         * Whether features are loaded based on range.  If not, pixels on screen
+         * is used.  Default = range
+         */
+         optional<bool>& useRange() { return _useRange; }
+         const optional<bool>& useRange() const { return _useRange; }
+
+        /**
+         * When using pixel size on screen instead of range, this specifies the maximum
+         * number of pixels at which to display the feature at a given LOD
+         */
+         optional<float>& maxPixels() { return _maxPixels;}
+         const optional<float>& maxPixels() const { return _maxPixels;}
+
+        /**
+         * When using pixel size on screen instead of range, this specifies the minimum
+         * number of pixels at which to display the feature at a given LOD
+         */
+         optional<float>& minPixels() { return _minPixels; }
+         const optional<float>& minPixels() const { return _minPixels; }
+
         /**
          * Whether to crop geometry to fit within the cell extents when chopping
          * a feature level up into grid cells. By default, this is false, meaning 
@@ -184,6 +205,9 @@ namespace osgEarth
         optional<float> _tileSizeFactor;
         optional<float> _minRange;
         optional<float> _maxRange;
+        optional<float> _minPixels;
+        optional<float> _maxPixels;
+        optional<bool>  _useRange;
         optional<bool>  _cropFeatures;
         optional<float> _priorityOffset;
         optional<float> _priorityScale;

src/osgEarth/FeatureDisplayLayout.cpp

@@ -71,6 +71,9 @@ FeatureDisplayLayout::FeatureDisplayLayout( const Config& conf ) :
 _tileSizeFactor( 3.5f ),
 _minRange      ( 0.0f ),
 _maxRange      ( 0.0f ),
+_minPixels     ( 0.0f ),
+_maxPixels     ( 0.0f ),
+_useRange      ( true ),
 _cropFeatures  ( false ),
 _priorityOffset( 0.0f ),
 _priorityScale ( 1.0f ),
@@ -91,6 +94,9 @@ FeatureDisplayLayout::fromConfig( const Config& conf )
     conf.get( "min_expiry_time",  _minExpiryTime );
     conf.get( "min_range",        _minRange );
     conf.get( "max_range",        _maxRange );
+    conf.get( "min_pixels",       _minPixels);
+    conf.get( "max_pixels",       _maxPixels);
+    conf.get( "use_range",        _useRange);
     conf.get("paged", _paged);
     ConfigSet children = conf.children( "level" );
     for( ConfigSet::const_iterator i = children.begin(); i != children.end(); ++i )
@@ -109,6 +115,9 @@ FeatureDisplayLayout::getConfig() const
     conf.set( "min_expiry_time",  _minExpiryTime );
     conf.set( "min_range",        _minRange );
     conf.set( "max_range",        _maxRange );
+    conf.set( "min_pixels",       _minPixels );
+    conf.set( "max_pixels",       _maxPixels );
+    conf.set( "use_range",        _useRange );
     conf.set("paged", _paged);
     for( Levels::const_iterator i = _levels.begin(); i != _levels.end(); ++i )
         conf.add( i->second.getConfig() );

src/osgEarth/FeatureModelGraph.cpp

@@ -269,8 +269,20 @@ namespace
         p->setLoadFunction(func);
         p->setCenter(bs.center());
         p->setRadius(bs.radius());
-        p->setMinRange(minRange);
-        p->setMaxRange(maxRange);
+        if( layout.useRange().get() )
+        {    
+            p->setMinRange(minRange);
+            p->setMaxRange(maxRange);
+        }
+        else
+        {
+            if( layout.minPixels().isSet() )
+                p->setMinPixels(layout.minPixels().get());
+
+            if( layout.maxPixels().isSet() )
+                p->setMaxPixels(layout.maxPixels().get());
+        }
+
         p->setPriorityScale(layout.priorityScale().get());
         p->setSceneGraphCallbacks(sgCallbacks);
         return p;

src/osgEarth/SimplePager

@@ -65,6 +65,8 @@ namespace osgEarth { namespace Util
         float getPriorityOffset() const { return _priorityOffset; }
         void setPriorityOffset(float value) { _priorityOffset = value; }
 
+        void setMinPixel(float value) { _minPixel = value; _useRange = false; }
+
         void setEnableCancelation(bool value);
         bool getEnableCancelation() const;
 
@@ -120,6 +122,8 @@ namespace osgEarth { namespace Util
 
         bool _additive;
         double _rangeFactor;
+        bool _useRange;
+        float _minPixel;
         unsigned int _minLevel;
         unsigned int _maxLevel;
         osg::ref_ptr<const Profile> _profile;

src/osgEarth/SimplePager.cpp

@@ -23,6 +23,8 @@ SimplePager::SimplePager(const osgEarth::Map* map, const osgEarth::Profile* prof
 _map(map),
 _profile( profile ),
 _rangeFactor( 6.0 ),
+_useRange(true),
+_minPixel(0.0),
 _additive(false),
 _minLevel(0),
 _maxLevel(30),
@@ -235,8 +237,11 @@ SimplePager::createPagedNode(const TileKey& key, ProgressCallback* progress)
         loadRange = (float)(tileRadius * _rangeFactor);
         pagedNode->setRefinePolicy(_additive ? REFINE_ADD : REFINE_REPLACE);
     }
-
-    pagedNode->setMaxRange(loadRange);
+
+    if (_useRange)
+        pagedNode->setMaxRange(loadRange);
+    else
+        pagedNode->setMinPixels(_minPixel);
 
     //OE_INFO << "PagedNode2: key="<<key.str()<<" hasChildren=" << hasChildren << ", range=" << loadRange << std::endl;
 

src/osgEarth/TiledFeatureModelLayer

@@ -52,6 +52,7 @@ namespace osgEarth
             Options(const ConfigOptions& options);
             OE_OPTION_LAYER(FeatureSource, featureSource);
             OE_OPTION(bool, additive);
+            OE_OPTION(float, minPixel);
             virtual Config getConfig() const;
         protected: // LayerOptions
             virtual void mergeConfig(const Config& conf);        
@@ -79,6 +80,9 @@ namespace osgEarth
         void setAdditive(const bool& value);
         const bool& getAdditive() const;
 
+        void setMinPixel(const float& value);
+        const float& getMinPixel() const;
+
         //! Forces a rebuild on this FeatureModelLayer.
         void dirty();    
 

src/osgEarth/TiledFeatureModelLayer.cpp

@@ -48,8 +48,11 @@ GeometryCompilerOptions(options)
 void TiledFeatureModelLayer::Options::fromConfig(const Config& conf)
 {
     additive().setDefault(false);
+    minPixel().setDefault(512.0);
 
     conf.get("additive", additive());
+    conf.get("min_pixel", minPixel());
+
     featureSource().get(conf, "features");
 }
 
@@ -65,6 +68,7 @@ TiledFeatureModelLayer::Options::getConfig() const
     conf.merge(gcConf);
 
     conf.set("additive", additive());
+    conf.set("min_pixel", minPixel());
 
     featureSource().set(conf, "features");
 
@@ -82,6 +86,7 @@ void TiledFeatureModelLayer::Options::mergeConfig(const Config& conf)
 OE_LAYER_PROPERTY_IMPL(TiledFeatureModelLayer, bool, AlphaBlending, alphaBlending);
 OE_LAYER_PROPERTY_IMPL(TiledFeatureModelLayer, bool, EnableLighting, enableLighting);
 OE_LAYER_PROPERTY_IMPL(TiledFeatureModelLayer, bool, Additive, additive);
+OE_LAYER_PROPERTY_IMPL(TiledFeatureModelLayer, float, MinPixel, minPixel);
 
 TiledFeatureModelLayer::~TiledFeatureModelLayer()
 {
@@ -267,6 +272,11 @@ TiledFeatureModelLayer::create()
             fmg->setOwnerName(getName());
             fmg->setFilterChain(chain.get());
             fmg->setAdditive(*_options->additive());
+            if (_options->minPixel().isSet())
+            {
+                fmg->setMinPixel(_options->minPixel().get());
+            }
+
             fmg->build();
 
             _root->removeChildren(0, _root->getNumChildren());