fix #39455

qgis · Oct 22, 2020 · 560cc73 · 560cc73
1 parent 67e7825
commit 560cc73
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Showing 3 changed files with 25 additions and 1 deletion.
diff --git a/src/3d/mesh/qgsmeshterraingenerator.cpp b/src/3d/mesh/qgsmeshterraingenerator.cpp
@@ -27,6 +27,7 @@
 #include "qgsmeshlayer3drenderer.h"
 #include "qgsterrainentity_p.h"
 #include "qgsterraintextureimage_p.h"
+#include "qgsmeshlayerutils.h"
 
 
 QgsMeshTerrainTileLoader::QgsMeshTerrainTileLoader( QgsTerrainEntity *terrain, QgsChunkNode *node, QgsMeshLayer *layer, const QgsMesh3DSymbol *symbol )
@@ -171,6 +172,27 @@ void QgsMeshTerrainGenerator::readXml( const QDomElement &elem )
   mSymbol->readXml( elem.firstChildElement( "symbol" ), rwc );
 }
 
+float QgsMeshTerrainGenerator::heightAt( double x, double y, const Qgs3DMapSettings &map ) const
+{
+  Q_UNUSED( map );
+  if ( !meshLayer()->triangularMesh() )
+    return std::numeric_limits<float>::quiet_NaN();
+
+  const QgsTriangularMesh triangularMesh = *meshLayer()->triangularMesh();
+  QgsPointXY point( x, y );
+  int faceIndex = triangularMesh.faceIndexForPoint( point );
+  if ( faceIndex < 0 || faceIndex >= triangularMesh.triangles().count() )
+    return std::numeric_limits<float>::quiet_NaN();
+
+  const QgsMeshFace &face = triangularMesh.triangles().at( faceIndex );
+
+  QgsPoint p1 = triangularMesh.vertices().at( face.at( 0 ) );
+  QgsPoint p2 = triangularMesh.vertices().at( face.at( 1 ) );
+  QgsPoint p3 = triangularMesh.vertices().at( face.at( 2 ) );
+
+  return QgsMeshLayerUtils::interpolateFromVerticesData( p1, p2, p3, p1.z(), p2.z(), p3.z(), point );
+}
+
 QgsMesh3DSymbol *QgsMeshTerrainGenerator::symbol() const
 {
   return mSymbol.get();

diff --git a/src/3d/mesh/qgsmeshterraingenerator.h b/src/3d/mesh/qgsmeshterraingenerator.h
@@ -84,13 +84,13 @@ class _3D_EXPORT QgsMeshTerrainGenerator: public QgsTerrainGenerator
     QgsRectangle extent() const override;
     void writeXml( QDomElement &elem ) const override;
     void readXml( const QDomElement &elem ) override;
+    float heightAt( double x, double y, const Qgs3DMapSettings &map ) const override;
 
   private:
     QgsMapLayerRef mLayer;
     QgsCoordinateReferenceSystem mCrs;
     QgsCoordinateTransformContext mTransformContext;
     std::unique_ptr< QgsMesh3DSymbol > mSymbol;
-
 };
 
 #endif // QGSMESHTERRAINGENERATOR_H
diff --git a/tests/src/3d/testqgs3drendering.cpp b/tests/src/3d/testqgs3drendering.cpp
@@ -350,6 +350,8 @@ void TestQgs3DRendering::testMeshTerrain()
 
   QImage img = Qgs3DUtils::captureSceneImage( engine, scene );
   QVERIFY( renderCheck( "mesh_terrain_1", img, 40 ) );
+
+  QCOMPARE( meshTerrain->heightAt( 1500, 2200, *map ), 200 );
 }
 
 void TestQgs3DRendering::testExtrudedPolygons()