holesome/src/game/camera/tracking_view.cpp

#include "tracking_view.h"
#include "../../utilities/vector_utils.hpp"

TrackingView::TrackingView(float freeMoveRadius, float dynamicFollowRadius) : freeMoveRadius(freeMoveRadius),
                                                                              dynamicFollowRadius(dynamicFollowRadius),
                                                                              view(nullptr),
                                                                              hasViewChanged(false)
{
    trackables = std::vector<ITrackable *>();
    marker = new CircleObject(2, sf::Color::Yellow);
    Game::getInstance()->registerView(this);
}

TrackingView::~TrackingView()
{
    delete view;
    delete marker;
}

void TrackingView::lateUpdate()
{
    // Initialize if necessary
    if (view == nullptr)
    {
        initializeView();
    }

    processTrackableStates();

    // Update size
    // TODO: Update size based on length of tracked objects
    setSize(Game::getInstance()->window->getSize());

    if (!trackables.empty())
    {
        followTarget();
    }

    // Update window if necessary
    if (hasViewChanged)
    {
        Game::getInstance()->window->setView(*this->view);
        hasViewChanged = false;
    }
}

void TrackingView::initializeView()
{
    auto size = Game::getInstance()->window->getView().getSize();
    view = new sf::View({0, 0}, size);
}

void TrackingView::setSize(sf::Vector2u windowSize)
{
    // TODO: Maybe listen to resize events instead of checking every frame?
    // Is different?
    if (view->getSize().x == windowSize.x && view->getSize().y == windowSize.y)
    {
        // Nothing to do
        return;
    }

    sf::Vector2f viewSize = sf::Vector2f(windowSize.x, windowSize.y);
    view->setSize(viewSize);
    hasViewChanged = true;
}

sf::Vector2f TrackingView::getSize() const
{
    return view->getSize();
}

sf::Vector2f TrackingView::getCenter() const
{
    return view->getCenter();
}

void TrackingView::followTarget()
{
    auto trackingPoint = getCollectiveTrackingPoint();
    if (DEVELOPER_MODE) {
        marker->coordinates.set(IsometricCoordinates(trackingPoint));
    }

    // Calculate distance to target to check how to handle it
    auto currentCenter = view->getCenter();
    auto vectorToTarget = trackingPoint - currentCenter;
    float distanceToTarget = length(vectorToTarget);

    if (distanceToTarget <= freeMoveRadius)
    {
        // Nothing to do
        return;
    }

    // Move view to place tracking-point at edge of area
    auto deltaToDesiredView = normalize(vectorToTarget);

    if (distanceToTarget <= dynamicFollowRadius) {
        // Reduce delta to make it less jaring
        deltaToDesiredView *= VIEW_DYNAMIC_FOLLOW_SPEED * (distanceToTarget - freeMoveRadius);
    } else {
        // Hard follow
        deltaToDesiredView *= dynamicFollowRadius;
    }

    moveCenter(deltaToDesiredView);
}

void TrackingView::moveCenter(sf::Vector2<float> delta)
{
    view->move(delta);
    hasViewChanged = true;
}

void TrackingView::draw(sf::RenderWindow *window) const
{
    if (!DEVELOPER_MODE) {
        return;
    }

    marker->draw(window);
}

void TrackingView::addTrackable(ITrackable *trackable)
{
    trackables.push_back(trackable);
}

sf::Vector2f TrackingView::getCollectiveTrackingPoint() const
{
    sf::Vector2f minPoint = trackables[0]->getTrackablePosition();
    sf::Vector2f maxPoint = minPoint;

    // Find min and max point coordinates for x and y axis over all trackables
    for (auto trackable : trackables)
    {
        auto trackableCoordinates = trackable->getTrackablePosition();
        auto trackableSize = trackable->getTrackableSize();

        auto minPointX = trackableCoordinates.x - trackableSize.x / 2.f;
        auto maxPointX = trackableCoordinates.x + trackableSize.x / 2.f;
        auto minPointY = trackableCoordinates.y - trackableSize.y / 2.f;
        auto maxPointY = trackableCoordinates.y + trackableSize.y / 2.f;

        if (minPointX < minPoint.x)
        {
            minPoint.x = minPointX;
        }
        if (maxPointX > maxPoint.x)
        {
            maxPoint.x = maxPointX;
        }
        if (minPointY < minPoint.y)
        {
            minPoint.y = minPointY;
        }
        if (maxPointY > maxPoint.y)
        {
            maxPoint.y = maxPointY;
        }
    }

    return minPoint + (maxPoint - minPoint) / 2.f;
}

void TrackingView::processTrackableStates()
{
    // Remove trackables that have ended tracking
    std::remove_if(trackables.begin(), trackables.end(), [](ITrackable *trackable)
    {
        return trackable->getTrackableState() == TrackableState::END_TRACKING;
    });
}

void TrackingView::setCenter(sf::Vector2<float> newCenter)
{
    view->setCenter(newCenter);
    hasViewChanged = true;
}