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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2021                                                               *
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#ifndef __OPENSPACE_MODULE_SPACECRAFTINSTRUMENTS___RENDERABLEFOV___H__
#define __OPENSPACE_MODULE_SPACECRAFTINSTRUMENTS___RENDERABLEFOV___H__

#include <openspace/rendering/renderable.h>

#include <openspace/properties/scalar/boolproperty.h>
#include <openspace/properties/scalar/doubleproperty.h>
#include <openspace/properties/scalar/floatproperty.h>
#include <openspace/properties/vector/vec3property.h>
#include <openspace/util/spicemanager.h>
#include <ghoul/glm.h>
#include <ghoul/opengl/ghoul_gl.h>
#include <ghoul/opengl/uniformcache.h>

namespace ghoul::opengl {
    class ProgramObject;
    class Texture;
} // namespace ghoul::opengl

namespace openspace {

namespace documentation { struct Documentation; }

class RenderableFov : public Renderable {
public:
    RenderableFov(const ghoul::Dictionary& dictionary);

    void initializeGL() override;
    void deinitializeGL() override;

    bool isReady() const override;

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

    static documentation::Documentation Documentation();

private:
    // Checks the field of view of the instrument for the current \p time against all of
    // the potential targets are returns the first name of the target that is in field of
    // view, the previous target, or the closest target to the space craft. The second
    // return value is whether the target is currently in the field of view
    std::pair<std::string,bool> determineTarget(double time);

    void updateGPU();
    void insertPoint(std::vector<float>& arr, glm::vec4 p, glm::vec4 c);

    glm::vec3 squareColor(float t) const {
        return _colors.active.value() * t + _colors.square.value() * (1 - t);
    }

    glm::vec3 endColor(float t) const {
        return _colors.active.value() * t + _colors.intersectionEnd.value() * (1 - t);
    }

    glm::vec3 fovColor(float t) const {
        return _colors.active.value() * t + _colors.targetInFieldOfView.value() * (1 - t);
    }

    void computeIntercepts(const UpdateData& data, const std::string& target,
        bool isInFov);

    glm::dvec3 orthogonalProjection(const glm::dvec3& vecFov, double time,
        const std::string& target) const;
    glm::dvec3 checkForIntercept(const glm::dvec3& ray, double time,
        const std::string& target) const;

    // properties
    properties::FloatProperty _lineWidth;
    properties::BoolProperty _drawSolid;
    properties::DoubleProperty _standOffDistance;
    ghoul::opengl::ProgramObject* _program = nullptr;
    UniformCache(modelViewProjection, defaultColorStart, defaultColorEnd, activeColor,
        targetInFieldOfViewColor, intersectionStartColor, intersectionEndColor,
        squareColor, interpolation) _uniformCache;

    // instance variables
    bool _rebuild = false;

    bool _simplifyBounds = false;

    //std::vector<float> _fovBounds;
    //std::vector<float> _fovPlane;

    std::string _previousTarget;
    bool _drawFOV = false;

    struct {
        std::string spacecraft;
        std::string name;
        std::string referenceFrame;
        SpiceManager::AberrationCorrection aberrationCorrection;

        std::vector<glm::dvec3> bounds;
        glm::dvec3 boresight = glm::dvec3(0.0);
        std::vector<std::string> potentialTargets;
    } _instrument;

    float _interpolationTime = 0.f;

    struct RenderInformation {
        // Differentiating different vertex types
        using VertexColorType = int32_t;
        // This needs to be synced with the fov_vs.glsl shader
        static const VertexColorType VertexColorTypeDefaultStart = 0;
        static const VertexColorType VertexColorTypeDefaultEnd = 1;
        static const VertexColorType VertexColorTypeInFieldOfView = 2;
        static const VertexColorType VertexColorTypeActive = 3;
        static const VertexColorType VertexColorTypeIntersectionStart = 4;
        static const VertexColorType VertexColorTypeIntersectionEnd = 5;
        static const VertexColorType VertexColorTypeSquare = 6;

        struct VBOData {
            GLfloat position[3];
            VertexColorType color;
        };

        GLuint vao = 0;
        GLuint vbo = 0;
        // @SPEEDUP: Add an ibo to reduce the number of vertices drawn
        std::vector<VBOData> data;
        bool isDirty = true;
    };

    RenderInformation _orthogonalPlane;
    RenderInformation _fieldOfViewBounds;

    struct {
        properties::Vec3Property defaultStart; // Start color for uninteresting times
        properties::Vec3Property defaultEnd; // End color for uninteresting times
        properties::Vec3Property active; // Color use when a field-of-view is projecting
        properties::Vec3Property targetInFieldOfView; // Color to use for target in fov
        properties::Vec3Property intersectionStart; // Color at the start of intersection
        properties::Vec3Property intersectionEnd; // Color at the end of intersection
        properties::Vec3Property square; // Color for the orthogonal square
    } _colors;
};

} // namespace openspace

#endif // __OPENSPACE_MODULE_SPACECRAFTINSTRUMENTS___RENDERABLEFOV___H__