qgstriangularmesh.h

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/***************************************************************************
                         qgstriangularmesh.h
                         -------------------
    begin                : April 2018
    copyright            : (C) 2018 by Peter Petrik
    email                : zilolv at gmail dot com
 ***************************************************************************/
 
/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSTRIANGULARMESH_H
#define QGSTRIANGULARMESH_H
 
 
#define SIP_NO_FILE
 
#include <memory>
 
#include "qgis_core.h"
#include "qgscoordinatetransform.h"
#include "qgsgeometry.h"
#include "qgsmeshdataprovider.h"
#include "qgsmeshspatialindex.h"
#include "qgstopologicalmesh.h"
 
#include <QList>
#include <QSet>
#include <QVector>
#include <QVector3D>
 
class QgsRenderContext;
class QgsRectangle;

class CORE_EXPORT QgsTriangularMesh // TODO rename to QgsRendererMesh in QGIS 4
{
  public:
 
    QgsTriangularMesh();
    ~QgsTriangularMesh();

    bool update( QgsMesh *nativeMesh, const QgsCoordinateTransform &transform );

    bool update( QgsMesh *nativeMesh );

    const QVector<QgsMeshVertex> &vertices() const ;

    const QVector<QgsMeshFace> &triangles() const ;

    const QVector<QgsMeshEdge> &edges() const ;

    Q_DECL_DEPRECATED const QVector<QgsMeshVertex> &centroids() const ;

    const QVector<QgsMeshVertex> &faceCentroids() const ;

    const QVector<QgsMeshVertex> &edgeCentroids() const ;

    const QVector<int> &trianglesToNativeFaces() const ;

    const QVector<int> &edgesToNativeEdges() const ;

    QgsPointXY transformFromLayerToTrianglesCoordinates( const QgsPointXY &point ) const;

    int faceIndexForPoint( const QgsPointXY &point ) const ;

    int faceIndexForPoint_v2( const QgsPointXY &point ) const;

    int nativeFaceIndexForPoint( const QgsPointXY &point ) const ;

    QList<int> nativeFaceIndexForRectangle( const QgsRectangle &rectangle ) const ;

    QList<int> faceIndexesForRectangle( const QgsRectangle &rectangle ) const ;

    QList<int> edgeIndexesForRectangle( const QgsRectangle &rectangle ) const ;

 
    QVector<QVector3D> vertexNormals( float vertScale ) const;

    QVector<QgsTriangularMesh *> simplifyMesh( double reductionFactor, int minimumTrianglesCount = 10 ) const;

    double averageTriangleSize() const;

    int levelOfDetail() const;

    QgsRectangle extent() const;

    bool contains( const QgsMesh::ElementType &type ) const;

    class Changes
    {
      public:

        Changes() = default;

        Changes( const QgsTopologicalMesh::Changes &topologicalChanges, const QgsMesh &nativeMesh );
 
      private:
        // triangular mesh elements that can be changed if the triangular mesh is updated, are not stored and have to be retrieve
        QVector<QgsMeshVertex> mAddedVertices;
        QList<int> mVerticesIndexesToRemove;
        QList<int> mChangedVerticesCoordinates;
        mutable QList<double> mOldZValue;
        QList<double> mNewZValue;
        QList<QgsPointXY> mOldXYValue;
        QList<QgsPointXY> mNewXYValue;
 
        QVector<QgsMeshFace> mNativeFacesToAdd;
        QList<int> mNativeFaceIndexesToRemove;
        QVector<QgsMeshFace> mNativeFacesToRemove;
        QList<int> mNativeFaceIndexesGeometryChanged;
        QVector<QgsMeshFace> mNativeFacesGeometryChanged;
        mutable QList<int> mTriangleIndexesGeometryChanged;
 
        mutable int mTrianglesAddedStartIndex = 0;  // defined each time the changes are apply
        mutable QList<int> mRemovedTriangleIndexes; // defined when changes are apply the first time
 
        friend class QgsTriangularMesh;
    };

    void applyChanges( const Changes &changes );

    void reverseChanges( const Changes &changes, const QgsMesh &nativeMesh );

    QgsMeshVertex nativeToTriangularCoordinates( const QgsMeshVertex &vertex ) const;

    QgsMeshVertex triangularToNativeCoordinates( const QgsMeshVertex &vertex ) const;

    QgsRectangle nativeExtent();
 
  private:

    void triangulate( const QgsMeshFace &face, int nativeIndex );
 
    void addVertex( const QgsMeshVertex &vertex );
 
    QgsMeshVertex transformVertex( const QgsMeshVertex &vertex, Qgis::TransformDirection direction ) const;
 
    // calculate the centroid of the native mesh, mNativeMeshCentroids container must have the emplacment for the corresponding centroid before calling this method
    QgsMeshVertex calculateCentroid( const QgsMeshFace &nativeFace ) const;
 
    // check clock wise and calculate average size of triangles
    void finalizeTriangles();
 
    // vertices: map CRS; 0-N ... native vertices, N+1 - len ... extra vertices
    // faces are derived triangles
    QgsMesh mTriangularMesh;
    QVector<int> mTrianglesToNativeFaces; //len(mTrianglesToNativeFaces) == len(mTriangles). Mapping derived -> native
    QVector<int> mEdgesToNativeEdges; //len(mEdgesToNativeEdges) == len(mEdges). Mapping derived -> native
 
    // centroids of the native faces in map CRS
    QVector<QgsMeshVertex> mNativeMeshFaceCentroids;
 
    // centroids of the native edges in map CRS
    QVector<QgsMeshVertex> mNativeMeshEdgeCentroids;
 
    QgsMeshSpatialIndex mSpatialFaceIndex;
    QgsMeshSpatialIndex mSpatialEdgeIndex;
    QgsCoordinateTransform mCoordinateTransform; //coordinate transform used to convert native mesh vertices to map vertices
 
    mutable QgsRectangle mExtent;
    mutable bool mIsExtentValid = false;
 
    // average size of the triangles
    double mAverageTriangleSize = 0;
    int mLod = 0;
 
    const QgsTriangularMesh *mBaseTriangularMesh = nullptr;
 
    friend class TestQgsTriangularMesh;
};
 
 
#endif // QGSTRIANGULARMESH_H