holesome/src/game/camera/tracking_view.cpp

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

TrackingView::TrackingView(TrackingViewOptions options) : options(options),
                                                          view(new sf::View(options.initialCenter,
                                                                            options.minViewSize)),
                                                          trackables({})
{
    marker = new CircleObject(DB_CIRCLE_RADIUS, sf::Color::Yellow);
}

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

void TrackingView::lateUpdate()
{
    processTrackableStates();

    if (!trackables.empty())
    {
        followTrackables();
    }
    adjustSizeToTrackables();
}

void TrackingView::setSize(sf::Vector2f newSize)
{
    // Is different?
    auto size = getSize();
    if (size.x == newSize.x && size.y == newSize.y)
    {
        // Nothing to do
        return;
    }

    bool didAspectRationChange = false;
    auto prevRatio = size.x / size.y;
    auto newRatio = newSize.x / newSize.y;
    if (abs(prevRatio - newRatio) > 0.001)
    {
        didAspectRationChange = true;
    }

    if (options.softResizeSpeed != 0 && !didAspectRationChange)
    {
        // Smooth out transition to new size
        newSize = size + (newSize - size) * options.softResizeSpeed * FRAME_TIME.asSeconds();
    }

    view->setSize(newSize);
}

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

sf::Vector2f TrackingView::getSizeInWindow() const
{
    auto size = Game::getInstance()->window->getSize();
    auto viewPort = view->getViewport();
    return {static_cast<float>(size.x * viewPort.width), static_cast<float>(size.y * viewPort.height)};
}

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

void TrackingView::followTrackables()
{
    auto trackingPoint = getTrackingArea().getCenter();
    if (DB_TRACKING_VIEW_CENTER)
    {
        marker->coordinates->setIsometric(IsometricCoordinates(trackingPoint));
    }

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

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



    // Targets are outside of free move radius, follow them
    auto deltaToDesiredView = normalize(vectorToTarget);

    // Reduce delta to edge of free-move area to make it less jaring
    deltaToDesiredView *= distanceToTarget - getFreeMovementRadius();

    moveCenter(deltaToDesiredView);
}

void TrackingView::moveCenter(sf::Vector2<float> delta)
{
    if (options.softFollowSpeed != 0)
    {
        // Soft
        delta *= options.softFollowSpeed * FRAME_TIME.asSeconds();
    }

    view->move(delta);
}

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

    marker->draw(window);
}

void TrackingView::addTrackable(const std::shared_ptr<ITrackable> &trackable)
{
    trackables.push_back(trackable);

    // Set initial values if first trackable
    if (trackables.size() == 1)
    {
        view->setCenter(trackable->getTrackablePosition());
    }
}

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

TrackingArea TrackingView::getTrackingArea() const
{
    if (trackables.empty())
    {
        return TrackingArea();
    }

    auto initialTrackable = trackables[0];
    TrackingArea area = {
            initialTrackable->getTrackablePosition() - initialTrackable->getTrackableSize() / 2.f,
            initialTrackable->getTrackablePosition() + initialTrackable->getTrackableSize() / 2.f
    };

    // 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 topLeft = trackableCoordinates - trackableSize / 2.f;
        auto bottomRight = trackableCoordinates + trackableSize / 2.f;

        if (topLeft.x < area.topLeft.x)
        {
            area.topLeft.x = topLeft.x;
        }
        if (bottomRight.x > area.bottomRight.x)
        {
            area.bottomRight.x = bottomRight.x;
        }
        if (topLeft.y < area.topLeft.y)
        {
            area.topLeft.y = topLeft.y;
        }
        if (bottomRight.y > area.bottomRight.y)
        {
            area.bottomRight.y = bottomRight.y;
        }
    }

    return area;
}

void TrackingView::adjustSizeToTrackables()
{
    // Calculate new view size
    auto newViewSize = getTrackingArea().getSize();

    newViewSize = applyPadding(newViewSize);
    newViewSize = restrainToBounds(newViewSize);

    // Extend view to match aspect ratio
    auto windowSize = getSizeInWindow();
    auto aspectRatio = windowSize.x / windowSize.y;
    if (newViewSize.x / newViewSize.y > aspectRatio)
    {
        // Extend x-axis
        newViewSize.y = newViewSize.x / aspectRatio;
    } else
    {
        // Extend y-axis
        newViewSize.x = newViewSize.y * aspectRatio;
    }

    setSize(newViewSize);
}

sf::Vector2f TrackingView::restrainToBounds(sf::Vector2f viewSize) const
{
    // x-axis
    if (options.minViewSize.x > 0 && viewSize.x < options.minViewSize.x)
    {
        viewSize.x = options.minViewSize.x;
    } else if (options.maxViewSize.x > 0 && viewSize.x > options.maxViewSize.x)
    {
        viewSize.x = options.maxViewSize.x;
    }
    // y-axis
    if (options.minViewSize.y > 0 && viewSize.y < options.minViewSize.y)
    {
        viewSize.y = options.minViewSize.y;
    } else if (options.maxViewSize.y > 0 && viewSize.y > options.maxViewSize.y)
    {
        viewSize.y = options.maxViewSize.y;
    }
    return viewSize;
}

sf::Vector2f TrackingView::applyPadding(sf::Vector2f viewSize) const
{
    auto padding = options.viewSizePadding;
    if (!options.isAbsoluteViewSizePadding)
    {
        padding.x *= viewSize.x;
        padding.y *= viewSize.y;
    }
    return viewSize + padding;
}

float TrackingView::getFreeMovementRadius() const
{
    if (options.freeMoveThreshold <= 0)
    {
        return 0;
    }

    if (options.isAbsoluteFreeMoveThreshold)
    {
        return options.freeMoveThreshold;
    }

    auto windowSize = getSizeInWindow();
    float smallestSide = std::min(windowSize.x, windowSize.y);

    // Only half of the side, since we are calculating radius
    return smallestSide / 2.f * options.freeMoveThreshold;
}

void TrackingView::removeTrackable(const std::shared_ptr<ITrackable> &trackable)
{
    trackables.erase(
            std::remove_if(trackables.begin(), trackables.end(), [&trackable](const std::shared_ptr<ITrackable> &t)
            {
                return t == trackable;
            }), trackables.end());
}

void TrackingView::setViewport(sf::Vector2f center, sf::Vector2f size)
{
    // TODO: Resize content for viewport
    view->setViewport(sf::FloatRect(center.x, center.y, size.x, size.y));
}

void TrackingView::setViewForWindow()
{
    Game::getInstance()->window->setView(*this->view);
}