OpenSpace/modules/globebrowsing/tile/tile.h

/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2016                                                               *
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#ifndef __OPENSPACE_MODULE_GLOBEBROWSING___TILE___H__
#define __OPENSPACE_MODULE_GLOBEBROWSING___TILE___H__

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

#include <ghoul/opengl/texture.h>

#include <cpl_error.h>
#include <memory>
#include <vector>

namespace openspace {
namespace globebrowsing {

struct TileMetaData {
    std::vector<float> maxValues;
    std::vector<float> minValues;
    std::vector<bool> hasMissingData;

    void serialize(std::ostream& s);
    static TileMetaData deserialize(std::istream& s);
};

struct TextureFormat {
    ghoul::opengl::Texture::Format ghoulFormat;
    GLuint glFormat;
};
    
using namespace ghoul::opengl;
    
struct RawTile {
    RawTile();

    char* imageData;
    glm::uvec3 dimensions;
    std::shared_ptr<TileMetaData> tileMetaData;
    TileIndex tileIndex;
    CPLErr error;
    size_t nBytesImageData;

    void serializeMetaData(std::ostream& s);
    static RawTile deserializeMetaData(std::istream& s);
   
    static RawTile createDefaultRes();
};

struct TileUvTransform {
    glm::vec2 uvOffset;
    glm::vec2 uvScale;
};

/**
 * Defines a status and may have a Texture and TileMetaData
 */
struct Tile {
    std::shared_ptr<Texture> texture;
    std::shared_ptr<TileMetaData> metaData;

    /**
     * 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 
    } status;
        
    /**
     * Instantiates a new tile with a single color. 
     * 
     * \param size The size of texture to be created
     * \param color defined RGBA values in range 0-255.
     *
     * \returns a Tile with status OK and the a texture 
     * with the requested size and color
     */
    static Tile createPlainTile(const glm::uvec2& size, const glm::uvec4& color);

    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;
};

} // namespace globebrowsing
} // namespace openspace


#endif  // __OPENSPACE_MODULE_GLOBEBROWSING___TILE___H__