OpenSpace/modules/globebrowsing/tile/tiledataset.h

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2017                                                               *
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#ifndef __OPENSPACE_MODULE_GLOBEBROWSING___TILE_DATASET___H__
#define __OPENSPACE_MODULE_GLOBEBROWSING___TILE_DATASET___H__

#include <modules/globebrowsing/tile/textureformat.h>
#include <modules/globebrowsing/tile/tile.h>
#include <modules/globebrowsing/tile/tiledepthtransform.h>
#include <modules/globebrowsing/tile/tiledatalayout.h>
#include <modules/globebrowsing/tile/tiledataset.h>
#include <modules/globebrowsing/tile/pixelregion.h>

#include <ghoul/glm.h>
#include <ghoul/opengl/ghoul_gl.h>
#include <ghoul/opengl/texture.h>

#include <gdal.h>
#include <string>

class GDALDataset;
class GDALRasterBand;

namespace openspace {
namespace globebrowsing {

class RawTile;
class GeodeticPatch;

class TileDataset {
public:
    struct Configuration {
        bool doPreProcessing;
        int minimumTilePixelSize;
        GLuint dataType = 0; // default = no datatype reinterpretation
    };

        
    /**
    * Opens a GDALDataset in readonly mode and calculates meta data required for 
    * reading tile using a TileIndex.
    *
    * \param gdalDatasetDesc  - A path to a specific file or raw XML describing the dataset 
    * \param minimumPixelSize - minimum number of pixels per side per tile requested 
    * \param datatype         - datatype for storing pixel data in requested tile
    */
    TileDataset(const std::string& gdalDatasetDesc, const Configuration& config);

    ~TileDataset();


    //////////////////////////////////////////////////////////////////////////////////
    //                              Public interface                                //
    //////////////////////////////////////////////////////////////////////////////////
    std::shared_ptr<RawTile> readTileData(TileIndex tileIndex);
    std::shared_ptr<RawTile> defaultTileData();
    int maxChunkLevel();
    TileDepthTransform getDepthTransform();
    const TileDataLayout& getDataLayout();
    void reset();
    float noDataValueAsFloat();


    const static glm::ivec2 tilePixelStartOffset;
    const static glm::ivec2 tilePixelSizeDifference;
    const static PixelRegion padding; // same as the two above


private:
    struct IODescription {
        struct ReadData {
            int overview;
            PixelRegion region;
        } read;
        
        struct WriteData {
            PixelRegion region;
            size_t bytesPerLine;
            size_t totalNumBytes;
        } write;
        
        IODescription cut(PixelRegion::Side side, int pos);
    };
    

    //////////////////////////////////////////////////////////////////////////////////
    //                                Initialization                                //
    //////////////////////////////////////////////////////////////////////////////////

    void initialize();
    void ensureInitialized();
    TileDepthTransform calculateTileDepthTransform();
    int calculateTileLevelDifference(int minimumPixelSize);


    //////////////////////////////////////////////////////////////////////////////////
    //                            GDAL helper methods                               //
    //////////////////////////////////////////////////////////////////////////////////

    void gdalEnsureInitialized();
    void setGdalProxyConfiguration();
    GDALDataset* gdalDataset(const std::string& gdalDatasetDesc);
    bool gdalHasOverviews() const;
    int gdalOverview(const PixelRegion::PixelRange& baseRegionSize) const;
    int gdalOverview(const TileIndex& tileIndex) const;
    int gdalVirtualOverview(const TileIndex& tileIndex) const;
    PixelRegion gdalPixelRegion(const GeodeticPatch& geodeticPatch) const;
    PixelRegion gdalPixelRegion(GDALRasterBand* rasterBand) const;
    GDALRasterBand* gdalRasterBand(int overview, int raster = 1) const;


    //////////////////////////////////////////////////////////////////////////////////
    //                          ReadTileData helper functions                       //
    //////////////////////////////////////////////////////////////////////////////////

    /**
        Returns the geo transform from raster space to projection coordinates as defined
        by GDAL.

        If the transform is not available, the function returns a transform to map
        the pixel coordinates to cover the whole geodetic lat long space.
    */
    std::array<double, 6> getGeoTransform() const;

    PixelRegion::PixelCoordinate geodeticToPixel(const Geodetic2& geo) const;
    Geodetic2 pixelToGeodetic(const PixelRegion::PixelCoordinate& p) const;
    IODescription getIODescription(const TileIndex& tileIndex) const;
    char* readImageData(IODescription& io, CPLErr& worstError) const;
    CPLErr rasterIO(GDALRasterBand* rasterBand, const IODescription& io, char* dst) const;
    CPLErr repeatedRasterIO(GDALRasterBand* rasterBand, const IODescription& io, char* dst, int depth = 0) const;
    std::shared_ptr<TileMetaData> getTileMetaData(std::shared_ptr<RawTile> result, const PixelRegion& region) const;
    CPLErr postProcessErrorCheck(std::shared_ptr<const RawTile> ioResult, const IODescription& io) const;



    //////////////////////////////////////////////////////////////////////////////////
    //                              Member variables                                //
    //////////////////////////////////////////////////////////////////////////////////

    // init data
    struct InitData {
        std::string initDirectory;
        std::string gdalDatasetDesc;
        int minimumPixelSize;
        GLuint dataType;
    } _initData;
        
    struct Cached {
        int _maxLevel = -1;
        double _tileLevelDifference;
    } _cached;

    const Configuration _config;


    GDALDataset* _dataset;
    TileDepthTransform _depthTransform;
    TileDataLayout _dataLayout;

    static bool GdalHasBeenInitialized;
    bool hasBeenInitialized;
};

} // namespace globebrowsing
} // namespace openspace

#endif // __OPENSPACE_MODULE_GLOBEBROWSING___TILE_DATASET___H__