OpenSpace/modules/globebrowsing/tile/tile.h

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

#include <modules/globebrowsing/tile/tileindex.h>
#include <modules/globebrowsing/tile/tileuvtransform.h>

#include <memory>

namespace ghoul { namespace opengl {
    class Texture;
}}

namespace openspace {
namespace globebrowsing {

struct TileMetaData;
struct TileUvTransform;

/**
 * Defines a status and may have a Texture and TileMetaData
 */
class Tile {
public:
     /**
     * Describe if this Tile is good for usage (OK) or otherwise
     * the reason why it is not.
     */
    enum class Status {
        /**
         * E.g when texture data is not currently in memory.
         * texture and tileMetaData are both null
         */
        Unavailable,

        /**
         * Can be set by <code>TileProvider</code>s if the requested
         * <code>TileIndex</code> is undefined for that particular
         * provider.
         * texture and metaData are both null
         */
        OutOfRange,

        /**
         * An IO Error happend
         * texture and metaData are both null
         */
        IOError,

        /**
         * The Texture is uploaded to the GPU and good for usage.
         * texture is defined. metaData may be defined.
         */
        OK
    };
    
    Tile(ghoul::opengl::Texture* texture,
         std::shared_ptr<TileMetaData> metaData,
         Status status);
    ~Tile() = default;

    std::shared_ptr<TileMetaData> metaData() const { return _metaData; };
    Status status() const { return _status; };
    ghoul::opengl::Texture* texture() const {
        return _texture;
    };

    static glm::vec2 compensateSourceTextureSampling(glm::vec2 startOffset, 
        glm::vec2 sizeDiff, glm::uvec2 resolution, glm::vec2 tileUV);
    static glm::vec2 TileUvToTextureSamplePosition(const TileUvTransform& uvTransform,
        glm::vec2 tileUV, glm::uvec2 resolution);
    /**
    * A tile with status unavailable that any user can return to
    * indicate that a tile was unavailable.
    */
    static const Tile TileUnavailable;

private:
    ghoul::opengl::Texture* _texture;
    std::shared_ptr<TileMetaData> _metaData;
    Status _status;
};

} // namespace globebrowsing
} // namespace openspace


#endif // __OPENSPACE_MODULE_GLOBEBROWSING___TILE___H__