OpenSpace/modules/globebrowsing/rendering/layershadermanager.h

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

#include <modules/globebrowsing/rendering/layer/layermanager.h>

#include <array>
#include <string>

namespace ghoul {
namespace opengl {
class ProgramObject;
}
}

namespace openspace {
namespace globebrowsing {

class RenderableGlobe;

/**
 * This class has ownership of an updated shader program for rendering tiles.
 */
class LayerShaderManager {
public:
    /**
     * Data needed for shader preprocessing before compiling a layered texture shader
     * program.
     *
     * If a <code>LayerShaderPreprocessingData</code> is compared with another it can
     * be determined wheter or not a <code>LayerShaderManager</code> needs to
     * recompile its shader program. For each <code>TextureGroup</code> there is
     * information about how many layers it has and whether or not to blend the texture
     * levels.
     */
    struct LayerShaderPreprocessingData {
        /**
         * Settings per texture group that contains shader preprocessing information.
         */
        struct LayerGroupPreprocessingData {
            int lastLayerIdx;
            bool layerBlendingEnabled;
            bool operator==(const LayerGroupPreprocessingData& other) const;
        };
        
        std::array<LayerGroupPreprocessingData, layergroupid::NUM_LAYER_GROUPS>
        layeredTextureInfo;
        std::vector<std::pair<std::string, std::string> > keyValuePairs;
        bool operator==(const LayerShaderPreprocessingData& other) const;

        static LayerShaderPreprocessingData get(const RenderableGlobe&);
    };
    
    LayerShaderManager(
        const std::string& shaderName,
        const std::string& vsPath,
        const std::string& fsPath);
    ~LayerShaderManager();

    /**
     * Returns a pointer to a <code>ProgramObject</code> for rendering tiles.
     */
    ghoul::opengl::ProgramObject* programObject() const;

    bool updatedOnLastCall();
    
    void recompileShaderProgram(LayerShaderPreprocessingData preprocessingData);

private:
        
    std::unique_ptr<ghoul::opengl::ProgramObject> _programObject;
    LayerShaderPreprocessingData _preprocessingData;

    const std::string _shaderName;
    const std::string _vsPath;
    const std::string _fsPath;

    bool _updatedOnLastCall;
};

} // namespace globebrowsing
} // namespace openspace

#endif // __OPENSPACE_MODULE_GLOBEBROWSING___LAYER_SHADER_MANAGER___H__