qgsquantizedmeshtiles.h

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/***************************************************************************
                             qgsquantizedmeshtiles.h
                             ----------------------------
    begin                : May 2024
    copyright            : (C) 2024 by David Koňařík
    email                : dvdkon at konarici dot cz
 
 ***************************************************************************
 *                                                                         *
 *   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 QGSQUANTIZEDMESHTILED_H
#define QGSQUANTIZEDMESHTILED_H
 
#include "qgis_core.h"
#include "qgsexception.h"
#include "qgsmeshdataprovider.h"
#include "qgsrectangle.h"
 
#include <qbytearray.h>
 
#define SIP_NO_FILE
 
#define TINYGLTF_NO_STB_IMAGE       // we use QImage-based reading of images
#define TINYGLTF_NO_STB_IMAGE_WRITE // we don't need writing of images
#include "tiny_gltf.h"
 
 
// Definition copied from format spec: https://github.com/CesiumGS/quantized-mesh
#pragma pack( push, 1 )
struct QgsQuantizedMeshHeader
{
    // The center of the tile in Earth-centered Fixed coordinates.
    double CenterX;
    double CenterY;
    double CenterZ;
 
    // The minimum and maximum heights in the area covered by this tile.
    // The minimum may be lower and the maximum may be higher than
    // the height of any vertex in this tile in the case that the min/max vertex
    // was removed during mesh simplification, but these are the appropriate
    // values to use for analysis or visualization.
    float MinimumHeight;
    float MaximumHeight;
 
    // The tile’s bounding sphere.  The X,Y,Z coordinates are again expressed
    // in Earth-centered Fixed coordinates, and the radius is in meters.
    double BoundingSphereCenterX;
    double BoundingSphereCenterY;
    double BoundingSphereCenterZ;
    double BoundingSphereRadius;
 
    // The horizon occlusion point, expressed in the ellipsoid-scaled Earth-centered Fixed frame.
    // If this point is below the horizon, the entire tile is below the horizon.
    // See http://cesiumjs.org/2013/04/25/Horizon-culling/ for more information.
    double HorizonOcclusionPointX;
    double HorizonOcclusionPointY;
    double HorizonOcclusionPointZ;
 
    uint32_t vertexCount;
};
#pragma pack( pop )

class CORE_EXPORT QgsQuantizedMeshParsingException : public QgsException
{
  public:
    using QgsException::QgsException;
};
 
struct CORE_EXPORT QgsQuantizedMeshTile
{
    QgsQuantizedMeshHeader mHeader;
    std::vector<uint16_t> mVertexCoords;
    std::vector<float> mNormalCoords;
    std::vector<uint32_t> mTriangleIndices;
    std::vector<uint32_t> mWestVertices;
    std::vector<uint32_t> mSouthVertices;
    std::vector<uint32_t> mEastVertices;
    std::vector<uint32_t> mNorthVertices;
    std::map<uint8_t, std::vector<char>> mExtensions;
 
    QgsQuantizedMeshTile( const QByteArray &data );
    // For some reason, commonly available QM tiles often have a very high (as
    // much as 50%) percentage of degenerate triangles. They don't harm our
    // rendering, but removing them could improve performance and makes working
    // with the data easier.
    void removeDegenerateTriangles();
    void generateNormals();
    tinygltf::Model toGltf( bool addSkirt = false, double skirtDepth = 0, bool withTextureCoords = false );
    // Make sure to call removeDegenerateTriangles() beforehand!
    QgsMesh toMesh( QgsRectangle tileBounds );
};
 
#endif // QGSQUANTIZEDMESHTILED_H