XMLGameEngine - engine.cpp

// engine.cpp
// XML Game Engine
// author: beefviper
// date: Sept 18, 2020

#include "engine.h"

xge::Engine::Engine(xge::Game& game) :
    game(game)
{
    xge::WindowDesc windowDesc = game.getWindowDesc();

    std::string name = windowDesc.name;

    int width = static_cast<int>(windowDesc.width);
    int height = static_cast<int>(windowDesc.height);
    sf::VideoMode videoMode(width, height);

    auto windowMode = (windowDesc.fullscreen == "true") ? sf::Style::Fullscreen : sf::Style::Default;

    window.create(videoMode, name, windowMode);
    window.setFramerateLimit(windowDesc.framerate);
}

sf::RenderWindow& xge::Engine::getWindow(void)
{
    return window;
}

bool xge::Engine::isRunning(void)
{
    return window.isOpen();
}

void xge::Engine::loop(void)
{
    while (window.isOpen())
    {
        sf::Event event;
        while (window.pollEvent(event))
        {
            switch (event.type)
            {
            case sf::Event::Closed:
                window.close();
                break;

            case sf::Event::KeyPressed:
                handleKeyPressed(game, event);
                break;

            case sf::Event::KeyReleased:
                handleKeyReleased(game, event);
                break;

            default:
                break;
            }
        }

        game.updateObjects();

        window.clear(xge::sfmlColor(game.getWindowDesc().background));

        for (auto name : game.getCurrentState().show)
        {
            window.draw(*game.getObject(name).sprite);
        }

        window.display();
    }
}

void xge::Engine::handleKeyPressed(xge::Game& game, sf::Event& event)
{
    if (!isKeyPressed[event.key.code])
    {
        isKeyPressed[event.key.code] = true;

        for (auto input : game.getCurrentState().input)
        {
            execute_action(game, event, input, true);
        }
    }
}

void xge::Engine::handleKeyReleased(xge::Game& game, sf::Event& event)
{

    isKeyPressed[event.key.code] = false;

    for (auto input : game.getCurrentState().input)
    {
        execute_action(game, event, input, false);
    }
}

void xge::Engine::execute_action(xge::Game& game, sf::Event& event, PairStringString& input, bool keyPressed)
{
    if (input.second == sfmlKeyToString(event.key.code))
    {

        std::string aObject = getObjectFromInput(input);
        std::string aCommand = getCommandFromInput(input);

        std::string aAction;

        if (aObject == "state")
        {
            if (keyPressed)
            {
                game.setCurrentState(aCommand);
            }
        }
        else if (&game.getObject(aObject) != nullptr)
        {
            aAction = game.getObject(aObject).action[aCommand];

            auto aStep = getValueFromAction(aAction);

            if (!keyPressed)
            {
                aStep = -aStep;
            }

            move(game.getObject(aObject), aCommand, aStep);
        }
    }
}

void xge::Engine::move(xge::Object& object, Engine::Direction direction, float step)
{
    switch (direction)
    {
    case Direction::Up:
        object.velocity.y -= step;
        break;
    case Direction::Down:
        object.velocity.y += step;
        break;
    case Direction::Left:
        object.velocity.x -= step;
        break;
    case Direction::Right:
        object.velocity.x += step;
        break;
    }
}

void xge::Engine::move(xge::Object& object, std::string direction, float step)
{
    move(object, mapDirection[direction], step);
}

std::string xge::Engine::getObjectFromInput(PairStringString input)
{
    auto sStart = 0;
    auto sEnd = input.first.find(".");
    return input.first.substr(sStart, sEnd);
}

std::string xge::Engine::getCommandFromInput(PairStringString input)
{
    auto sStart = input.first.rfind('.') + 1;
    auto sEnd = input.first.length();
    auto sLength = sEnd - sStart;

    return input.first.substr(sStart, sLength);
}

float xge::Engine::getValueFromAction(std::string action)
{
    auto sStart = action.find("(") + 1;
    auto sEnd = action.find(")");
    auto sLength = sEnd - sStart;
    auto sVar = action.substr(sStart, sLength);

    return game.getVariable(sVar);
}