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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2024                                                               *
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#include <modules/spacecraftinstruments/rendering/renderablemodelprojection.h>

#include <modules/spacecraftinstruments/util/imagesequencer.h>
#include <openspace/documentation/documentation.h>
#include <openspace/documentation/verifier.h>
#include <openspace/engine/globals.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/scene/scene.h>
#include <openspace/util/distanceconversion.h>
#include <openspace/util/updatestructures.h>
#include <ghoul/filesystem/filesystem.h>
#include <ghoul/io/model/modelgeometry.h>
#include <ghoul/io/model/modelreader.h>
#include <ghoul/logging/logmanager.h>
#include <ghoul/opengl/textureunit.h>

namespace {
    constexpr openspace::properties::Property::PropertyInfo PerformShadingInfo = {
        "PerformShading",
        "Perform Shading",
        "If true, the model will be shaded based on the location of the Sun. If false, "
        "shading is disabled and the model is fully illuminated.",
        openspace::properties::Property::Visibility::NoviceUser
    };

    struct [[codegen::Dictionary(RenderableModelProjection)]] Parameters {
        // The file or files that should be loaded, that specifies the model to load. The
        // file can contain filesystem tokens or can be specified relative to the
        // location of the asset file.
        std::filesystem::path geometryFile;

        enum class [[codegen::map(openspace::DistanceUnit)]] ScaleUnit {
            Nanometer,
            Micrometer,
            Millimeter,
            Centimeter,
            Decimeter,
            Meter,
            Kilometer,
            Thou,
            Inch,
            Foot,
            Yard,
            Chain,
            Furlong,
            Mile
        };

        // The scale of the model. For example if the model is in centimeters
        // then `ModelScale = \"Centimeter\"` or `ModelScale = 0.01`.
        std::optional<std::variant<ScaleUnit, double>> modelScale;

        // By default the given `ModelScale` is used to scale down the model. By setting
        // this setting to true the scaling is inverted to that the model is instead
        // scaled up with the given `ModelScale`.
        std::optional<bool> invertModelScale;

        // Contains information about projecting onto this planet.
        ghoul::Dictionary projection
            [[codegen::reference("spacecraftinstruments_projectioncomponent")]];

        // [[codegen::verbatim(PerformShadingInfo.description)]]
        std::optional<bool> performShading;
    };
#include "renderablemodelprojection_codegen.cpp"
} // namespace

namespace openspace {

documentation::Documentation RenderableModelProjection::Documentation() {
    return codegen::doc<Parameters>("spacecraftinstruments_renderablemodelprojection");
}

RenderableModelProjection::RenderableModelProjection(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
    , _performShading(PerformShadingInfo, true)
{
    const Parameters p = codegen::bake<Parameters>(dictionary);

    const std::filesystem::path file = absPath(p.geometryFile);
    _geometry = ghoul::io::ModelReader::ref().loadModel(
        file,
        ghoul::io::ModelReader::ForceRenderInvisible::No,
        ghoul::io::ModelReader::NotifyInvisibleDropped::Yes
    );

    _invertModelScale = p.invertModelScale.value_or(_invertModelScale);

    if (p.modelScale.has_value()) {
        if (std::holds_alternative<Parameters::ScaleUnit>(*p.modelScale)) {
            const Parameters::ScaleUnit scaleUnit =
                std::get<Parameters::ScaleUnit>(*p.modelScale);
            const DistanceUnit distanceUnit = codegen::map<DistanceUnit>(scaleUnit);
            _modelScale = toMeter(distanceUnit);
        }
        else if (std::holds_alternative<double>(*p.modelScale)) {
            _modelScale = std::get<double>(*p.modelScale);
        }
        else {
            throw ghoul::MissingCaseException();
        }

        if (_invertModelScale) {
            _modelScale = 1.0 / _modelScale;
        }
    }

    addPropertySubOwner(_projectionComponent);
    _projectionComponent.initialize(identifier(), p.projection);

    _performShading = p.performShading.value_or(_performShading);
    addProperty(_performShading);
}

RenderableModelProjection::~RenderableModelProjection() {}

bool RenderableModelProjection::isReady() const {
    return (_programObject != nullptr) && _projectionComponent.isReady();
}

void RenderableModelProjection::initializeGL() {
    _programObject = global::renderEngine->buildRenderProgram(
        "ModelShader",
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModel_vs.glsl"),
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModel_fs.glsl")
    );

    ghoul::opengl::updateUniformLocations(*_programObject, _mainUniformCache);

    _fboProgramObject = ghoul::opengl::ProgramObject::Build(
        "ProjectionPass",
        absPath(
            "${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelProjection_vs.glsl"
        ),
        absPath(
            "${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelProjection_fs.glsl"
        )
    );

    ghoul::opengl::updateUniformLocations(*_fboProgramObject, _fboUniformCache);

    _depthFboProgramObject = ghoul::opengl::ProgramObject::Build(
        "DepthPass",
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelDepth_vs.glsl"),
        absPath("${MODULE_SPACECRAFTINSTRUMENTS}/shaders/renderableModelDepth_fs.glsl")
    );

    ghoul::opengl::updateUniformLocations(*_depthFboProgramObject, _depthFboUniformCache);

    _projectionComponent.initializeGL();

    _geometry->initialize();
    _geometry->calculateBoundingRadius();
    setBoundingSphere(_geometry->boundingRadius() * _modelScale);

    // Set Interaction sphere size to be 10% of the bounding sphere
    setInteractionSphere(boundingSphere() * 0.1);
}

void RenderableModelProjection::deinitializeGL() {
    if (_geometry) {
        _geometry->deinitialize();
    }

    _geometry = nullptr;

    _projectionComponent.deinitialize();

    global::renderEngine->removeRenderProgram(_programObject.get());
    _programObject = nullptr;
}

ghoul::opengl::Texture& RenderableModelProjection::baseTexture() const {
    return _projectionComponent.projectionTexture();
}

void RenderableModelProjection::render(const RenderData& data, RendererTasks&) {
    if (_projectionComponent.needsClearProjection()) {
        _projectionComponent.clearAllProjections();
    }

    const glm::vec3 up = data.camera.lookUpVectorCameraSpace();

    if (_shouldCapture && _projectionComponent.doesPerformProjection()) {
        for (const Image& i : _imageTimes) {
            try {
                const glm::mat4 projectorMat = attitudeParameters(i.timeRange.start, up);
                const std::shared_ptr<ghoul::opengl::Texture> t =
                    _projectionComponent.loadProjectionTexture(i.path, i.isPlaceholder);
                imageProjectGPU(*t, projectorMat);
            }
            catch (const SpiceManager::SpiceException& e) {
                LERRORC(e.component, e.what());
            }
        }
        _shouldCapture = false;
    }

    _programObject->activate();

    try {
        attitudeParameters(data.time.j2000Seconds(), up);
    }
    catch (const SpiceManager::SpiceException& e) {
        LERRORC(e.component, e.what());
    }
    _imageTimes.clear();

    // Calculate variables to be used as uniform variables in shader
    const glm::vec3 bodyPos = data.modelTransform.translation;

    // Model transform and view transform needs to be in double precision
    const glm::dmat4 modelTransform = glm::scale(
        calcModelTransform(data), glm::dvec3(_modelScale)
    );
    const glm::dmat4 modelViewTransform = calcModelViewTransform(data, modelTransform);

    // malej 2023-FEB-23: The light sources should probably not be hard coded
    const glm::vec3 directionToSun = glm::normalize(_sunPosition - bodyPos);
    const glm::vec3 directionToSunViewSpace = glm::normalize(
        glm::mat3(data.camera.combinedViewMatrix()) * directionToSun
    );

    _programObject->setUniform(_mainUniformCache.performShading, _performShading);
    _programObject->setUniform(
        _mainUniformCache.directionToSunViewSpace,
        directionToSunViewSpace
    );
    _programObject->setUniform(
        _mainUniformCache.modelViewTransform,
        glm::mat4(modelViewTransform)
    );
    _programObject->setUniform(
        _mainUniformCache.projectionTransform,
        data.camera.projectionMatrix()
    );
    _programObject->setUniform(
        _mainUniformCache.projectionFading,
        _projectionComponent.projectionFading()
    );

    ghoul::opengl::TextureUnit baseUnit;
    baseUnit.activate();
    _programObject->setUniform(_mainUniformCache.baseTexture, baseUnit);

    ghoul::opengl::TextureUnit projectionUnit;
    projectionUnit.activate();
    _projectionComponent.projectionTexture().bind();
    _programObject->setUniform(_mainUniformCache.projectionTexture, projectionUnit);

    _geometry->render(*_programObject, false);

    _programObject->deactivate();
}

void RenderableModelProjection::update(const UpdateData& data) {
    if (_programObject->isDirty()) {
        _programObject->rebuildFromFile();

        ghoul::opengl::updateUniformLocations(*_programObject, _mainUniformCache);
    }

    if (_fboProgramObject->isDirty()) {
        _fboProgramObject->rebuildFromFile();

        ghoul::opengl::updateUniformLocations(*_fboProgramObject, _fboUniformCache);
    }

    _projectionComponent.update();

    if (_depthFboProgramObject->isDirty()) {
        _depthFboProgramObject->rebuildFromFile();

        ghoul::opengl::updateUniformLocations(
            *_depthFboProgramObject,
            _depthFboUniformCache
        );
    }

    const double time = data.time.j2000Seconds();
    const double integrateFromTime = data.previousFrameTime.j2000Seconds();

    // Only project new images if time changed since last update.
    if (time > integrateFromTime && ImageSequencer::ref().isReady() &&
        _projectionComponent.doesPerformProjection())
    {
        _imageTimes = ImageSequencer::ref().imagePaths(
            _projectionComponent.projecteeId(),
            _projectionComponent.instrumentId(),
            time,
            integrateFromTime
        );
        _shouldCapture = !_imageTimes.empty();
    }

    glm::dmat3 stateMatrix = data.modelTransform.rotation;
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            _transform[i][j] = static_cast<float>(stateMatrix[i][j]);
        }
    }

    SceneGraphNode* sun = global::renderEngine->scene()->sceneGraphNode("Sun");
    if (sun) {
        _sunPosition = sun->worldPosition() - data.modelTransform.translation;
    }
    else {
        // If the Sun node doesn't exist, we assume that the light source is in the origin
        _sunPosition = -data.modelTransform.translation;
    }
}

void RenderableModelProjection::imageProjectGPU(
                                          const ghoul::opengl::Texture& projectionTexture,
                                                         const glm::mat4& projectorMatrix)
{
    if (_projectionComponent.needsShadowMap()) {
        _projectionComponent.depthMapRenderBegin();
        _depthFboProgramObject->activate();
        _depthFboProgramObject->setUniform(
            _depthFboUniformCache.ProjectorMatrix,
            projectorMatrix
        );
        _depthFboProgramObject->setUniform(
            _depthFboUniformCache.ModelTransform,
            _transform
        );

        _geometry->render(*_fboProgramObject, false, true);

        _depthFboProgramObject->deactivate();
        _projectionComponent.depthMapRenderEnd();
    }

    _projectionComponent.imageProjectBegin();
    _fboProgramObject->activate();

    ghoul::opengl::TextureUnit unitFbo;
    unitFbo.activate();
    projectionTexture.bind();
    _fboProgramObject->setUniform(_fboUniformCache.projectionTexture, unitFbo);

    _fboProgramObject->setUniform(
        _fboUniformCache.needShadowMap,
        _projectionComponent.needsShadowMap()
    );

    ghoul::opengl::TextureUnit unitDepthFbo;
    if (_projectionComponent.needsShadowMap()) {
        unitDepthFbo.activate();
        _projectionComponent.depthTexture().bind();
        _fboProgramObject->setUniform(_fboUniformCache.depthTexture, unitDepthFbo);
    }

    _fboProgramObject->setUniform(_fboUniformCache.ProjectorMatrix, projectorMatrix);
    _fboProgramObject->setUniform(_fboUniformCache.ModelTransform, _transform);
    _fboProgramObject->setUniform(_fboUniformCache.boresight, _boresight);

    _geometry->render(*_fboProgramObject, false, true);

    _fboProgramObject->deactivate();
    _projectionComponent.imageProjectEnd();
}

glm::mat4 RenderableModelProjection::attitudeParameters(double time, const glm::vec3& up)
{
    _instrumentMatrix = SpiceManager::ref().positionTransformMatrix(
        _projectionComponent.instrumentId(),
        "GALACTIC",
        time
    );

    SpiceManager::FieldOfViewResult res = SpiceManager::ref().fieldOfView(
        _projectionComponent.instrumentId()
    );
    _boresight = std::move(res.boresightVector);

    double lightTime = 0.0;
    const glm::dvec3 p = SpiceManager::ref().targetPosition(
        _projectionComponent.projectorId(),
        _projectionComponent.projecteeId(),
        "GALACTIC",
        _projectionComponent.aberration(),
        time,
        lightTime
    );

    const glm::vec3 cpos = p * 10000.0;

    const float distance = glm::length(cpos);
    const double radius = boundingSphere();
    return _projectionComponent.computeProjectorMatrix(
        cpos,
        _boresight,
        up,
        _instrumentMatrix,
        _projectionComponent.fieldOfViewY(),
        _projectionComponent.aspectRatio(),
        static_cast<float>(distance - radius),
        static_cast<float>(distance + radius),
        _boresight
    );
}

}  // namespace openspace