Move conversion of tesselation to multipolygon to QgsTessellator

Also - add unit test - fix bad tesselation due to missing origins
qgis · Nov 26, 2017 · 006da6e · 006da6e
1 parent c0e732b
commit 006da6e
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Showing 4 changed files with 63 additions and 32 deletions.
diff --git a/src/3d/processing/qgsalgorithmtesselate.cpp b/src/3d/processing/qgsalgorithmtesselate.cpp
@@ -74,33 +74,6 @@ QgsTesselateAlgorithm *QgsTesselateAlgorithm::createInstance() const
   return new QgsTesselateAlgorithm();
 }
 
-QgsPoint getPointFromData( QVector< float >::const_iterator &it )
-{
-  // tesselator geometry is x, z, -y
-  double x = *it;
-  ++it;
-  double z = *it;
-  ++it;
-  double y = -( *it );
-  ++it;
-  return QgsPoint( x, y, z );
-}
-
-void tesselatePolygon( const QgsPolygon *polygon, QgsMultiPolygon *destination )
-{
-  QgsTessellator t( 0, 0, false );
-  t.addPolygon( *polygon, 0 );
-
-  QVector<float> data = t.data();
-  for ( auto it = data.constBegin(); it != data.constEnd(); )
-  {
-    QgsPoint p1 = getPointFromData( it );
-    QgsPoint p2 = getPointFromData( it );
-    QgsPoint p3 = getPointFromData( it );
-    destination->addGeometry( new QgsTriangle( p1, p2, p3 ) );
-  }
-}
-
 QgsFeature QgsTesselateAlgorithm::processFeature( const QgsFeature &feature, QgsProcessingFeedback * )
 {
   QgsFeature f = feature;
@@ -110,22 +83,26 @@ QgsFeature QgsTesselateAlgorithm::processFeature( const QgsFeature &feature, Qgs
       f.clearGeometry();
     else
     {
-      std::unique_ptr< QgsMultiPolygon > mp = qgis::make_unique< QgsMultiPolygon >();
+      QgsRectangle bounds = f.geometry().boundingBox();
+      QgsTessellator t( bounds.xMinimum(), bounds.yMinimum(), false );
+
       if ( f.geometry().isMultipart() )
       {
         const QgsMultiSurface *ms = qgsgeometry_cast< const QgsMultiSurface * >( f.geometry().constGet() );
         for ( int i = 0; i < ms->numGeometries(); ++i )
         {
           std::unique_ptr< QgsPolygon > p( qgsgeometry_cast< QgsPolygon * >( ms->geometryN( i )->segmentize() ) );
-          tesselatePolygon( p.get(), mp.get() );
+          t.addPolygon( *p, 0 );
         }
       }
       else
       {
         std::unique_ptr< QgsPolygon > p( qgsgeometry_cast< QgsPolygon * >( f.geometry().constGet()->segmentize() ) );
-        tesselatePolygon( p.get(), mp.get() );
+        t.addPolygon( *p, 0 );
       }
-      f.setGeometry( QgsGeometry( std::move( mp ) ) );
+      QgsGeometry g( t.asMultiPolygon() );
+      g.translate( bounds.xMinimum(), bounds.yMinimum() );
+      f.setGeometry( g );
     }
   }
   return f;

diff --git a/src/3d/qgstessellator.cpp b/src/3d/qgstessellator.cpp
@@ -17,8 +17,10 @@
 
 #include "qgscurve.h"
 #include "qgsgeometry.h"
+#include "qgsmultipolygon.h"
 #include "qgspoint.h"
 #include "qgspolygon.h"
+#include "qgstriangle.h"
 #include "qgis_sip.h"
 
 #include "poly2tri/poly2tri.h"
@@ -397,3 +399,29 @@ void QgsTessellator::addPolygon( const QgsPolygon &polygon, float extrusionHeigh
       _makeWalls( *polygon.interiorRing( i ), true, extrusionHeight, mData, mAddNormals, mOriginX, mOriginY );
   }
 }
+
+QgsPoint getPointFromData( QVector< float >::const_iterator &it )
+{
+  // tesselator geometry is x, z, -y
+  double x = *it;
+  ++it;
+  double z = *it;
+  ++it;
+  double y = -( *it );
+  ++it;
+  return QgsPoint( x, y, z );
+}
+
+std::unique_ptr<QgsMultiPolygon> QgsTessellator::asMultiPolygon() const
+{
+  std::unique_ptr< QgsMultiPolygon > mp = qgis::make_unique< QgsMultiPolygon >();
+  const QVector<float> data = mData;
+  for ( auto it = data.constBegin(); it != data.constEnd(); )
+  {
+    QgsPoint p1 = getPointFromData( it );
+    QgsPoint p2 = getPointFromData( it );
+    QgsPoint p3 = getPointFromData( it );
+    mp->addGeometry( new QgsTriangle( p1, p2, p3 ) );
+  }
+  return mp;
+}
diff --git a/src/3d/qgstessellator.h b/src/3d/qgstessellator.h
@@ -19,9 +19,10 @@
 #include "qgis_3d.h"
 
 class QgsPolygon;
+class QgsMultiPolygon;
 
 #include <QVector>
-
+#include <memory>
 
 /**
  * \ingroup 3d
@@ -48,6 +49,11 @@ class _3D_EXPORT QgsTessellator
     //! Returns size of one vertex entry in bytes
     int stride() const { return mStride; }
 
+    /**
+     * Returns the triangulation as a multipolygon geometry.
+     */
+    std::unique_ptr< QgsMultiPolygon > asMultiPolygon() const;
+
   private:
     double mOriginX, mOriginY;
     bool mAddNormals;

diff --git a/tests/src/3d/testqgstessellator.cpp b/tests/src/3d/testqgstessellator.cpp
@@ -20,6 +20,7 @@
 #include "qgspoint.h"
 #include "qgspolygon.h"
 #include "qgstessellator.h"
+#include "qgsmultipolygon.h"
 
 /**
  * Simple structure to record an expected triangle from tessellator.
@@ -115,6 +116,7 @@ class TestQgsTessellator : public QObject
 
     void testBasic();
     void testWalls();
+    void asMultiPolygon();
 
   private:
 };
@@ -191,6 +193,24 @@ void TestQgsTessellator::testWalls()
   QVERIFY( checkTriangleOutput( tZ.data(), false, tc ) );
 }
 
+void TestQgsTessellator::asMultiPolygon()
+{
+  QgsPolygon polygon;
+  polygon.fromWkt( "POLYGON((1 1, 2 1, 3 2, 1 2, 1 1))" );
+
+  QgsPolygon polygonZ;
+  polygonZ.fromWkt( "POLYGONZ((1 1 1, 2 1 2, 3 2 3, 1 2 4, 1 1 1))" );
+
+  QgsTessellator t( 0, 0, false );
+  t.addPolygon( polygon, 0 );
+  QCOMPARE( t.asMultiPolygon()->asWkt(), QStringLiteral( "MultiPolygonZ (((1 2 0, 2 1 0, 3 2 0, 1 2 0)),((1 2 0, 1 1 0, 2 1 0, 1 2 0)))" ) );
+
+  QgsTessellator t2( 0, 0, false );
+  t2.addPolygon( polygonZ, 0 );
+  QCOMPARE( t2.asMultiPolygon()->asWkt(), QStringLiteral( "MultiPolygonZ (((1 2 4, 2 1 2, 3 2 3, 1 2 4)),((1 2 4, 1 1 1, 2 1 2, 1 2 4)))" ) );
+
+}
+
 
 QGSTEST_MAIN( TestQgsTessellator )
 #include "testqgstessellator.moc"