From 17756d53f839ab922456a7ff7b56e614d1851d41 Mon Sep 17 00:00:00 2001
From: Glenn Waldron <gwaldron@gmail.com>
Date: Thu, 10 Oct 2024 14:49:21 -0400
Subject: [PATCH] FeatureImage: add simple point rasterization (with demo)

---
 src/osgEarth/FeatureRasterizer.cpp | 23 ++++++++++++++++
 src/osgEarth/Geometry              | 43 +++++++++++++++++++++++-------
 src/osgEarth/Geometry.cpp          | 26 +++++++++---------
 tests/feature_rasterize.earth      | 16 ++++++++++-
 4 files changed, 84 insertions(+), 24 deletions(-)

diff --git a/src/osgEarth/FeatureRasterizer.cpp b/src/osgEarth/FeatureRasterizer.cpp
index 34a7ccdb66..c754467cea 100644
--- a/src/osgEarth/FeatureRasterizer.cpp
+++ b/src/osgEarth/FeatureRasterizer.cpp
@@ -723,6 +723,7 @@ FeatureRasterizer::render_blend2d(
     _inverted = true;
 
     // find the symbology:
+    const PointSymbol* masterPoint = style.get<PointSymbol>();
     const LineSymbol* masterLine = style.getSymbol<LineSymbol>();
     const PolygonSymbol* masterPoly = style.getSymbol<PolygonSymbol>();
     const CoverageSymbol* masterCov = style.getSymbol<CoverageSymbol>();
@@ -865,6 +866,28 @@ FeatureRasterizer::render_blend2d(
         }
     }
 
+    if (masterPoint)
+    {
+        float width = masterPoint->size().value();
+
+        ctx.setFillStyle(BLRgba(
+            masterPoint->fill()->color().r(), masterPoint->fill()->color().g(), masterPoint->fill()->color().b(), masterPoint->fill()->color().a()));
+
+        for (const auto& feature : features)
+        {
+            feature->getGeometry()->forEachPart([&](const Geometry* part)
+                {
+                    for (auto& p : *part)
+                    {
+                        double x = frame.xf * (p.x() - frame.xmin);
+                        double y = frame.yf * (p.y() - frame.ymin);
+                        y = ctx.targetHeight() - y;
+                        ctx.fillCircle(x, y, width / 2.0);
+                    }
+                });
+        }
+    }
+
     if (masterText || masterSkin)
     {   
         // Sort the features based their location.  We do this to ensure that features collected in a metatiling
diff --git a/src/osgEarth/Geometry b/src/osgEarth/Geometry
index 95e00e1208..813ecc5b28 100644
--- a/src/osgEarth/Geometry
+++ b/src/osgEarth/Geometry
@@ -256,17 +256,18 @@ namespace osgEarth
         //! Whether a closed geometry contains the 2D point
         virtual bool contains2D(double x, double y) const { return false; }
 
-        //! Iterate over all the parts of a geometry
-        void forEachPart(const std::function<void(Geometry*)>& func) { forEachPart(true, func); }
 
-        //! Iterate over all the parts of a geometry
-        void forEachPart(bool includePolygonHoles, const std::function<void(Geometry*)>& func);
+        //! Iterate over all the parts of a geometry (signature = void(Geometry* part))
+        template<typename CALLABLE>
+        inline void forEachPart(bool includePolygonHoles, CALLABLE&& func);
+        template<typename CALLABLE>
+        inline void forEachPart(CALLABLE&& func) { forEachPart(true, func); };
 
-        //! Iterate over all the parts of a geometry
-        void forEachPart(const std::function<void(const Geometry*)>& func) const { forEachPart(true, func); }
-
-        //! Iterate over all the parts of a geometry
-        void forEachPart(bool includePolygonHoles, const std::function<void(const Geometry*)>& func) const;
+        //! Iterate over all the parts of a CONST geometry (signature = void(const Geometry* part))
+        template<typename CALLABLE>
+        inline void forEachPart(bool includePolygonHoles, CALLABLE&& func) const;
+        template<typename CALLABLE>
+        inline void forEachPart(CALLABLE&& func) const { forEachPart(true, func); };
 
     public:
         inline Type getType() const { return _type; }
@@ -560,7 +561,9 @@ namespace osgEarth
         const Geometry* next();
 
         //! Visits each part and calls a user-defined functor
-        inline void forEach(const std::function<void(const Geometry* part)>& func) {
+        //! Signature = void(const Geometry* part)
+        template<typename CALLABLE>
+        inline void forEach(CALLABLE&& func) { //const std::function<void(const Geometry* part)>& func) {
             while (hasMore()) func(next());
         }
 
@@ -620,6 +623,26 @@ namespace osgEarth
         bool _closeLoop;
         Segment _current;
     };
+
+
+
+    //! Iterate over all the parts of a geometry
+    template<typename CALLABLE>
+    inline void Geometry::forEachPart(bool includePolygonHoles, CALLABLE&& func)
+    {
+        GeometryIterator i(this, includePolygonHoles);
+        i.forEach(func);
+    }
+
+    //! Iterate over all the parts of a geometry
+    template<typename CALLABLE>
+    inline void Geometry::forEachPart(bool includePolygonHoles, CALLABLE&& func) const
+    {
+        ConstGeometryIterator i(this, includePolygonHoles);
+        i.forEach(func);
+    }
+
+
 } // namespace osgEarth
 
 
diff --git a/src/osgEarth/Geometry.cpp b/src/osgEarth/Geometry.cpp
index 957f925762..ca0a6fc41d 100644
--- a/src/osgEarth/Geometry.cpp
+++ b/src/osgEarth/Geometry.cpp
@@ -696,19 +696,19 @@ Geometry::close()
         push_back( front() );
 }
 
-void
-Geometry::forEachPart(bool includePolygonHoles, const std::function<void(Geometry*)>& func)
-{
-    GeometryIterator i(this, includePolygonHoles);
-    i.forEach(func);
-}
-
-void
-Geometry::forEachPart(bool includePolygonHoles, const std::function<void(const Geometry*)>& func) const
-{
-    ConstGeometryIterator i(this, includePolygonHoles);
-    i.forEach(func);
-}
+//void
+//Geometry::forEachPart(bool includePolygonHoles, const std::function<void(Geometry*)>& func)
+//{
+//    GeometryIterator i(this, includePolygonHoles);
+//    i.forEach(func);
+//}
+//
+//void
+//Geometry::forEachPart(bool includePolygonHoles, const std::function<void(const Geometry*)>& func) const
+//{
+//    ConstGeometryIterator i(this, includePolygonHoles);
+//    i.forEach(func);
+//}
 
 //----------------------------------------------------------------------------
 
diff --git a/tests/feature_rasterize.earth b/tests/feature_rasterize.earth
index d41d881eea..e6e5a543f7 100644
--- a/tests/feature_rasterize.earth
+++ b/tests/feature_rasterize.earth
@@ -10,7 +10,7 @@ FeatureImage - rasterizes feature data into an image layer.
         <url>../data/world.shp</url>
     </OGRFeatures>
     
-    <FeatureImage name="World Boundaries">
+    <FeatureImage name="Rasterized polygons + lines">
         <features>world-data</features>
         <styles>        
             <style type="text/css">
@@ -23,4 +23,18 @@ FeatureImage - rasterizes feature data into an image layer.
         </styles>
     </FeatureImage>
   
+    <FeatureImage name="Rasterized points" min_level="5">
+        <ogrfeatures url="../data/cities_mercator.shp"/>
+        <styles>
+            <script language="javascript">
+              <![CDATA[
+                function get_style() {
+                    var rank = feature.properties.scalerank;
+                    return "{ point-fill:#7f7fff;point-size:" + (rank*2.5) + "; }";
+                }
+              ]]>
+            </script>
+            <selector style_expr="get_style();"/>
+        </styles>        
+    </FeatureImage>
 </Map>