OpenSpace/modules/base/rendering/renderableconstellationbounds.h

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

#include <openspace/rendering/renderable.h>
#include <openspace/properties/scalarproperty.h>
#include <openspace/properties/selectionproperty.h>
#include <ghoul/opengl/programobject.h>
#include <array>

namespace openspace {

/**
 * This class renders the constellation bounds as defined in
 * http://cdsarc.u-strasbg.fr/viz-bin/Cat?cat=VI%2F49. It contains the bounds on the
 * celestial sky for the different constellations and is used to determine in which region
 * of the sky a specific object is located.
 * The bounds are drawn as lines on a sphere with variable radius, set by the
 * <code>_distance</code> property. Currently, all constellation bounds are lines, which
 * leads to artifacts if the radius is very small.
 * Renderable configuration attributes:
 * <code>File</code> [string] (required): The file that contains the bounds and the
 * abbreviations for the different constellations
 * <code>ConstellationFile</code> [string]: The file that contains the mapping between
 * abbreviations and full names. If the file is omitted, the abbreviations are used as the
 * full names.
 * <code>ReferenceFrame</code> [string]: The reference frame in which the points contained
 * in the <code>File</code> are stored in. Defaults to <code>J2000</code>
 */
class RenderableConstellationBounds : public Renderable {
public:
	RenderableConstellationBounds(const ghoul::Dictionary& dictionary);
	~RenderableConstellationBounds();

	bool initialize() override;
	bool deinitialize() override;

	bool isReady() const override;

	void render(const RenderData& data) override;
	void update(const UpdateData& data) override;

private:
	/// Stores the constellation bounds
	struct ConstellationBound {
		std::string constellationAbbreviation; ///< The abbreviation of the constellation
		std::string constellationFullName;
		bool isEnabled;
		size_t startIndex; ///< The index of the first vertex describing the bounds
		size_t nVertices; ///< The number of vertices describing the bounds
	};

	/**
	 * Loads the file specified in <code>_vertexFilename</code> and fills the
	 * <code>_constellationBounds</code> variable, as well as the
	 * <code>_vertexValues</code> list. If this method fails, the content of either
	 * destination is undefined.
	 * \return <code>true</code> if the loading succeeded, <code>false</code> otherwise
	 */
	bool loadVertexFile();

	/**
	 * Loads the file specified in <code>_constellationFilename</code> that contains the
	 * mapping between abbreviations and full names of constellations.
	 * \return <code>true</code> if the loading succeeded, <code>false</code> otherwise
	 */
	bool loadConstellationFile();

	/// Fills the <code>_constellationSelection</code> property with all constellations
	void fillSelectionProperty();

	/**
	 * Callback method that gets triggered when <code>_constellationSelection</code>
	 * changes.
	 */
	void selectionPropertyHasChanged();

	std::string _vertexFilename; ///< The filename containing the constellation bounds
	std::string _constellationFilename; ///< The file containing constellation names

    std::unique_ptr<ghoul::opengl::ProgramObject> _program;

	/// The list of all loaded constellation bounds
	std::vector<ConstellationBound> _constellationBounds;
	
	typedef std::array<float, 3> Vertex;
	std::vector<Vertex> _vertexValues; ///< A list of all vertices of all bounds

	/// The radius of the celestial sphere onto which the bounds are drawn
	properties::FloatProperty _distance;

	/// The property that stores all indices of constellations that should be drawn
	properties::SelectionProperty _constellationSelection;

	std::string _originReferenceFrame; ///< Reference frame in which bounds are defined
	
	/// Used to translate between the origin reference frame and the target frame
	glm::dmat3 _stateMatrix;

	GLuint _vao;
	GLuint _vbo;
};

} // namespace openspace

#endif // __RENDERABLECONSTELLATIONBOUNDS_H__