Fix identify tool not finding points when using a single point click

and map crs != layer crs

python/core/auto_generated/pointcloud/qgspointclouddataprovider.sip.in

@@ -56,10 +56,10 @@ Ctor
 
     ~QgsPointCloudDataProvider();
 
-    QVector<QVariantMap> identify( double maxErrorInMapCoords, const QgsGeometry &extentGeometry, const QgsDoubleRange &extentZRange = QgsDoubleRange(), int pointsLimit = 1000 );
+    QVector<QVariantMap> identify( double maxError, const QgsGeometry &extentGeometry, const QgsDoubleRange &extentZRange = QgsDoubleRange(), int pointsLimit = 1000 );
 %Docstring
-Returns the list of points of the point cloud according to a  zoom level
-defined by ``maxErrorInMapCoords``, an extent ``geometry`` in the 2D plane
+Returns the list of points of the point cloud according to a zoom level
+defined by ``maxError`` (in layer coordinates), an extent ``geometry`` in the 2D plane
 and a range ``extentZRange`` for z values. The function will try to limit
 the number of points returned to ``pointsLimit`` points
 

src/core/pointcloud/qgspointclouddataprovider.cpp

@@ -318,7 +318,7 @@ struct MapIndexedPointCloudNode
 };
 
 QVector<QVariantMap> QgsPointCloudDataProvider::identify(
-  double maxErrorInMapCoords,
+  double maxError,
   const QgsGeometry &extentGeometry,
   const QgsDoubleRange &extentZRange, int pointsLimit )
 {
@@ -327,10 +327,10 @@ QVector<QVariantMap> QgsPointCloudDataProvider::identify(
   QgsPointCloudIndex *index = this->index();
   const IndexedPointCloudNode root = index->root();
 
-  QgsRectangle rootNodeExtentMapCoords = index->nodeMapExtent( root );
-  const double rootErrorInMapCoordinates = rootNodeExtentMapCoords.width() / index->span();
+  QgsRectangle rootNodeExtent = index->nodeMapExtent( root );
+  const double rootError = rootNodeExtent.width() / index->span();
 
-  QVector<IndexedPointCloudNode> nodes = traverseTree( index, root, maxErrorInMapCoords, rootErrorInMapCoordinates, extentGeometry, extentZRange );
+  QVector<IndexedPointCloudNode> nodes = traverseTree( index, root, maxError, rootError, extentGeometry, extentZRange );
 
   QgsPointCloudAttributeCollection attributeCollection = index->attributes();
   QgsPointCloudRequest request;

src/core/pointcloud/qgspointclouddataprovider.h

@@ -75,8 +75,8 @@ class CORE_EXPORT QgsPointCloudDataProvider: public QgsDataProvider
     ~QgsPointCloudDataProvider() override;
 
     /**
-     * Returns the list of points of the point cloud according to a  zoom level
-     * defined by \a maxErrorInMapCoords, an extent \a geometry in the 2D plane
+     * Returns the list of points of the point cloud according to a zoom level
+     * defined by \a maxError (in layer coordinates), an extent \a geometry in the 2D plane
      * and a range \a extentZRange for z values. The function will try to limit
      * the number of points returned to \a pointsLimit points
      *
@@ -85,7 +85,7 @@ class CORE_EXPORT QgsPointCloudDataProvider: public QgsDataProvider
      * \note this function does not handle elevation properties and you need to
      * change elevation coordinates yourself after returning from the function
      */
-    QVector<QVariantMap> identify( double maxErrorInMapCoords, const QgsGeometry &extentGeometry, const QgsDoubleRange &extentZRange = QgsDoubleRange(), int pointsLimit = 1000 );
+    QVector<QVariantMap> identify( double maxError, const QgsGeometry &extentGeometry, const QgsDoubleRange &extentZRange = QgsDoubleRange(), int pointsLimit = 1000 );
 
     /**
      * Returns flags containing the supported capabilities for the data provider.

src/core/pointcloud/qgspointcloudrenderer.cpp

@@ -204,17 +204,20 @@ QVector<QVariantMap> QgsPointCloudRenderer::identify( QgsPointCloudLayer *layer,
 
   const double maxErrorPixels = renderContext.convertToPainterUnits( maximumScreenError(), maximumScreenErrorUnit() );// in pixels
 
-  QgsRectangle rootNodeExtentMapCoords = index->nodeMapExtent( root );
+  const QgsRectangle rootNodeExtentLayerCoords = index->nodeMapExtent( root );
+  QgsRectangle rootNodeExtentMapCoords;
   try
   {
-    rootNodeExtentMapCoords = renderContext.coordinateTransform().transformBoundingBox( index->nodeMapExtent( root ) );
+    rootNodeExtentMapCoords = renderContext.coordinateTransform().transformBoundingBox( rootNodeExtentLayerCoords );
   }
   catch ( QgsCsException & )
   {
     QgsDebugMsg( QStringLiteral( "Could not transform node extent to map CRS" ) );
+    rootNodeExtentMapCoords = rootNodeExtentLayerCoords;
   }
 
-  const double rootErrorInMapCoordinates = rootNodeExtentMapCoords.width() / index->span(); // in map coords
+  const double rootErrorInMapCoordinates = rootNodeExtentMapCoords.width() / index->span();
+  const double rootErrorInLayerCoordinates = rootNodeExtentLayerCoords.width() / index->span();
 
   double mapUnitsPerPixel = renderContext.mapToPixel().mapUnitsPerPixel();
   if ( ( rootErrorInMapCoordinates < 0.0 ) || ( mapUnitsPerPixel < 0.0 ) || ( maxErrorPixels < 0.0 ) )
@@ -223,7 +226,8 @@ QVector<QVariantMap> QgsPointCloudRenderer::identify( QgsPointCloudLayer *layer,
     return selectedPoints;
   }
 
-  double maxErrorInMapCoordinates = maxErrorPixels * mapUnitsPerPixel;
+  const double maxErrorInMapCoordinates = maxErrorPixels * mapUnitsPerPixel;
+  const double maxErrorInLayerCoordinates = maxErrorInMapCoordinates * rootErrorInLayerCoordinates / rootErrorInMapCoordinates;
 
   QgsGeometry selectionGeometry = geometry;
   if ( geometry.type() == QgsWkbTypes::PointGeometry )
@@ -260,11 +264,20 @@ QVector<QVariantMap> QgsPointCloudRenderer::identify( QgsPointCloudLayer *layer,
     }
   }
 
-  selectedPoints = layer->dataProvider()->identify( maxErrorInMapCoordinates, selectionGeometry, renderContext.zRange() );
+  // selection geometry must be in layer CRS for QgsPointCloudDataProvider::identify
+  try
+  {
+    selectionGeometry.transform( renderContext.coordinateTransform(), QgsCoordinateTransform::ReverseTransform );
+  }
+  catch ( QgsCsException & )
+  {
+    QgsDebugMsg( QStringLiteral( "Could not transform geometry to layer CRS" ) );
+    return selectedPoints;
+  }
+
+  selectedPoints = layer->dataProvider()->identify( maxErrorInLayerCoordinates, selectionGeometry, renderContext.zRange() );
 
   selectedPoints.erase( std::remove_if( selectedPoints.begin(), selectedPoints.end(), [this]( const QMap<QString, QVariant> &point ) { return !this->willRenderPoint( point ); } ), selectedPoints.end() );
 
   return selectedPoints;
 }
-
-

src/core/pointcloud/qgspointcloudrenderer.h

@@ -284,8 +284,10 @@ class CORE_EXPORT QgsPointCloudRenderer
     /**
      * Returns the list of visible points of the point cloud layer \a layer and an extent defined by
      * a geometry in the 2D plane \a geometry.
+     *
+     * \warning The \a geometry value must be specified in the render context's destination CRS, not the layer's native CRS!
      */
-    QVector<QVariantMap> identify( QgsPointCloudLayer *layer, const QgsRenderContext &context,  const QgsGeometry &geometry ) SIP_SKIP;
+    QVector<QVariantMap> identify( QgsPointCloudLayer *layer, const QgsRenderContext &context, const QgsGeometry &geometry ) SIP_SKIP;
 
     /**
      * Checks whether the point holding \a pointAttributes attributes will be rendered

src/gui/qgsmaptoolidentify.cpp

@@ -508,25 +508,12 @@ bool QgsMapToolIdentify::identifyVectorTileLayer( QList<QgsMapToolIdentify::Iden
 bool QgsMapToolIdentify::identifyPointCloudLayer( QList<QgsMapToolIdentify::IdentifyResult> *results, QgsPointCloudLayer *layer, const QgsGeometry &geometry, const QgsIdentifyContext &identifyContext )
 {
   Q_UNUSED( identifyContext )
-  QgsCoordinateTransform ct( mCanvas->mapSettings().destinationCrs(), layer->crs(), mCanvas->mapSettings().transformContext() );
   QgsPointCloudRenderer *renderer = layer->renderer();
 
-  QgsGeometry transformedGeometry = geometry;
-
-  if ( ct.isValid() )
-  {
-    try
-    {
-      transformedGeometry.transform( ct );
-    }
-    catch ( QgsCsException & )
-    {
-      return false;
-    }
-  }
-
   QgsRenderContext context = QgsRenderContext::fromMapSettings( mCanvas->mapSettings() );
-  const QVector<QVariantMap> points = renderer->identify( layer, context, transformedGeometry );
+  context.setCoordinateTransform( QgsCoordinateTransform( layer->crs(), mCanvas->mapSettings().destinationCrs(), mCanvas->mapSettings().transformContext() ) );
+
+  const QVector<QVariantMap> points = renderer->identify( layer, context, geometry );
   int id = 0;
   const QgsPointCloudLayerElevationProperties *elevationProps = qobject_cast< const QgsPointCloudLayerElevationProperties *>( layer->elevationProperties() );
   for ( const QVariantMap &pt : points )