OpenSpace/modules/globebrowsing/tile/tileprovider/texttileprovider.h

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

#include <modules/globebrowsing/globebrowsingmodule.h>
#include <modules/globebrowsing/tile/tileprovider/tileprovider.h>
#include <modules/globebrowsing/cache/lrucache.h>
#include <modules/globebrowsing/tile/tiletextureinitdata.h>

#include <ghoul/opengl/ghoul_gl.h>

namespace ghoul { namespace fontrendering {
class Font;
class FontRenderer;
}}

namespace openspace {
namespace globebrowsing {
namespace tileprovider {

/**
 * Enables a simple way of providing tiles with any type of rendered text. 
 * Internally it handles setting up a FBO for rendering the text, and defines a new 
 * interface, consisting of only a single method for subclasses to implement: 
 * renderText(const FontRenderer&, const TileIndex&) const;
 */
class TextTileProvider : public TileProvider {
public:
    /**
     * Default constructor with default values for texture and font size
     */
    TextTileProvider(const TileTextureInitData& initData, size_t fontSize = 48);
    virtual ~TextTileProvider() override;

    // The TileProvider interface below is implemented in this class
    virtual Tile getTile(const TileIndex& tileIndex) override;
    virtual Tile::Status getTileStatus(const TileIndex& index) override;
    virtual TileDepthTransform depthTransform() override;
    virtual void update() override;
    virtual void reset() override;
    virtual int maxLevel() override;

    /**
     * Allow overriding of hash function. 
     * Default is <code>TileIndex::hashKey()</code>
     *
     * \param tileIndex tileIndex to hash
     * \returns hashkey used for in LRU cache for this tile
     */
    virtual TileIndex::TileHashKey toHash(const TileIndex& tileIndex) const;
        
    /**
     * Uses the fontRenderer to render some text onto the tile texture provided in 
     * backgroundTile(const TileIndex& tileIndex). 
     * 
     * \param fontRenderer used for rendering text onto texture
     * \param tileIndex associated with the tile to be rendered onto
     */
    virtual void renderText(const ghoul::fontrendering::FontRenderer& fontRenderer,
        const TileIndex& tileIndex) const = 0;

protected:
    const TileTextureInitData _initData;
    std::shared_ptr<ghoul::fontrendering::Font> _font;
    size_t _fontSize;

private:
    Tile
        createChunkIndexTile(const TileIndex& tileIndex);
    std::unique_ptr<ghoul::fontrendering::FontRenderer> _fontRenderer;
	
    GLuint _fbo;
  
    cache::MemoryAwareTileCache* _tileCache;
};

} // namespace tileprovider
} // namespace globebrowsing
} // namespace openspace

#endif // __OPENSPACE_MODULE_GLOBEBROWSING___TEXT_TILE_PROVIDER___H__