Added offsetCurve function to Geometry

gwaldron · Feb 5, 2025 · 7b044a2 · 7b044a2
1 parent b33f680
commit 7b044a2
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Showing 2 changed files with 65 additions and 3 deletions.
diff --git a/src/osgEarth/Geometry b/src/osgEarth/Geometry
@@ -35,13 +35,12 @@ namespace osgEarth
     public:
         enum CapStyle  { CAP_DEFAULT, CAP_SQUARE, CAP_ROUND, CAP_FLAT };
         enum JoinStyle { JOIN_ROUND, JOIN_MITRE, JOIN_BEVEL};
-        BufferParameters( CapStyle capStyle =CAP_DEFAULT, JoinStyle joinStyle = JOIN_ROUND, int cornerSegs =0, bool singleSided=false, bool leftSide=false )
-            : _capStyle(capStyle), _joinStyle(joinStyle),_cornerSegs(cornerSegs), _singleSided(singleSided), _leftSide(leftSide) { }
+        BufferParameters( CapStyle capStyle =CAP_DEFAULT, JoinStyle joinStyle = JOIN_ROUND, int cornerSegs =0, bool singleSided=false )
+            : _capStyle(capStyle), _joinStyle(joinStyle),_cornerSegs(cornerSegs), _singleSided(singleSided) { }
         CapStyle  _capStyle;
         JoinStyle _joinStyle;
         int       _cornerSegs; // # of line segment making up a rounded corner
         bool      _singleSided; //Whether or not to do a single sided buffer
-        bool      _leftSide;    //If doing a single sided buffer are we buffering to the left?  If false, buffer to the right
     };
 
     typedef std::vector<osg::Vec3d> Vec3dVector;
@@ -156,6 +155,18 @@ namespace osgEarth
             osg::ref_ptr<Geometry>& output,
             const BufferParameters& bp =BufferParameters() ) const;
 
+        /**
+         * Runs an offset curve operation on this geometry and returns the
+         * result in the output parameter. Returns true if the op succeeded.
+        */
+        bool offsetCurve(
+            double distance,
+            int quadSegs,
+            BufferParameters::JoinStyle joinStyle,
+            double mitreLimit,
+            osg::ref_ptr<Geometry>& output
+            ) const;
+
         /**
          * Crops this geometry to the region represented by the crop polygon, returning
          * the result in the output parameter. Returns true if the op succeeded.

diff --git a/src/osgEarth/Geometry.cpp b/src/osgEarth/Geometry.cpp
@@ -247,6 +247,57 @@ Geometry::buffer(double distance,
 #endif // OSGEARTH_HAVE_GEOS
 }
 
+bool
+Geometry::offsetCurve(
+    double distance,
+    int quadSegs,
+    BufferParameters::JoinStyle joinStyle,
+    double mitreLimit,
+    osg::ref_ptr<Geometry>& output
+    ) const
+{
+#ifdef OSGEARTH_HAVE_GEOS
+
+    GEOSContextHandle_t handle = initGEOS_r(OSGEARTH_WarningHandler, OSGEARTH_GEOSErrorHandler);
+
+    GEOSGeometry* inGeom = GEOS::importGeometry(handle, this);
+    if (inGeom)
+    {
+        int  geosJoinStyle =
+            joinStyle == BufferParameters::JOIN_ROUND ? GEOSBufJoinStyles::GEOSBUF_JOIN_ROUND :
+            joinStyle == BufferParameters::JOIN_MITRE ? GEOSBufJoinStyles::GEOSBUF_JOIN_MITRE :
+            joinStyle == BufferParameters::JOIN_BEVEL ? GEOSBufJoinStyles::GEOSBUF_JOIN_BEVEL :
+            GEOSBufJoinStyles::GEOSBUF_JOIN_ROUND;
+
+        GEOSGeometry* outGeom = NULL;
+        outGeom = GEOSOffsetCurve_r(handle, inGeom, distance, quadSegs, geosJoinStyle, mitreLimit);
+        if (outGeom)
+        {
+            output = GEOS::exportGeometry(handle, outGeom);
+            // If the z value of the geometry is nan set it to 0
+            for (auto& p : output->asVector())
+            {
+                if (std::isnan(p.z()))
+                    p.z() = 0.0;
+            }
+            GEOSGeom_destroy_r(handle, outGeom);
+        }
+
+        GEOSGeom_destroy_r(handle, inGeom);
+    }
+
+    finishGEOS_r(handle);
+
+    return output.valid();
+
+#else // OSGEARTH_HAVE_GEOS
+
+    OE_WARN << LC << "Offset Curve failed - GEOS not available" << std::endl;
+    return false;
+
+#endif // OSGEARTH_HAVE_GEOS
+}
+
 namespace
 {
     // Function to check if a point is inside the clipping edge