sfml-snake/src/Snake.cpp at main · Sam1624/sfml-snake · GitHub

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#include "Snake.hpp"
#include "Config.hpp"
#include <SFML/Graphics/RectangleShape.hpp>
#include <SFML/Graphics/RenderWindow.hpp>
#include <SFML/Window/Keyboard.hpp>


Snake::Snake(sf::RenderWindow& window) : m_window(window), m_dir(Direction::Right) {
    m_body.clear();

    sf::RectangleShape head;
    head.setSize({SNAKE_SEGMENT_SIZE, SNAKE_SEGMENT_SIZE});
    head.setFillColor(sf::Color::Green);
    head.setPosition({(float)WINDOW_WIDTH / 2, (float)WINDOW_HEIGHT / 2});
    m_body.push_back(head);

    sf::RectangleShape bodySegment;
    bodySegment.setSize({SNAKE_SEGMENT_SIZE, SNAKE_SEGMENT_SIZE});
    bodySegment.setFillColor(sf::Color(0, 150, 0));

    bodySegment.setPosition({(float)WINDOW_WIDTH / 2 - SNAKE_SEGMENT_SIZE, (float)WINDOW_HEIGHT / 2});
    m_body.push_back(bodySegment);

    bodySegment.setPosition({(float)WINDOW_WIDTH / 2 - SNAKE_SEGMENT_SIZE * 2, (float)WINDOW_HEIGHT / 2});
    m_body.push_back(bodySegment);
}

void Snake::Grow() {
    m_shouldGrow = true;
}

void Snake::HandleInput() {
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::W) && m_dir != Direction::Down) {
        m_dir = Direction::Up;
    }
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::S) && m_dir != Direction::Up) {
        m_dir = Direction::Down;
    }
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::A) && m_dir != Direction::Right) {
        m_dir = Direction::Left;
    }
    if (sf::Keyboard::isKeyPressed(sf::Keyboard::D) && m_dir != Direction::Left) {
        m_dir = Direction::Right;
    }
}

bool Snake::Update() {
    if (m_moveClock.getElapsedTime() >= m_moveInterval) {
        sf::Vector2f newHeadPos = m_body.front().getPosition();

        switch (m_dir) {
            case Direction::Up:    newHeadPos.y -= SNAKE_SEGMENT_SIZE; break;
            case Direction::Down:  newHeadPos.y += SNAKE_SEGMENT_SIZE; break;
            case Direction::Left:  newHeadPos.x -= SNAKE_SEGMENT_SIZE; break;
            case Direction::Right: newHeadPos.x += SNAKE_SEGMENT_SIZE; break;
            case Direction::None:  break;
        }

        sf::RectangleShape newHead;
        newHead.setSize({SNAKE_SEGMENT_SIZE, SNAKE_SEGMENT_SIZE});
        newHead.setFillColor(sf::Color::Green);
        newHead.setPosition(newHeadPos);

        m_body.push_front(newHead);
        if (m_body.size() > 1) {
            m_body[1].setFillColor(sf::Color(0, 150, 0));
        }

        if (m_shouldGrow) {
            m_shouldGrow = false;
        } else {
            m_body.pop_back();
        }

        m_moveClock.restart();
        return true;
    }
    return false;
}

sf::Vector2f lerp(const sf::Vector2f& start, const sf::Vector2f& end, float t) {
    return start + (end - start) * t;
}

void Snake::Draw() {
    float alpha = m_moveClock.getElapsedTime().asSeconds() / m_moveInterval.asSeconds();
    if (alpha > 1.0f) alpha = 1.0f;

    sf::RectangleShape segmentShape({SNAKE_SEGMENT_SIZE, SNAKE_SEGMENT_SIZE});

    sf::Vector2f headPos = m_body.front().getPosition();
    sf::Vector2f nextHeadPos = headPos;
    switch (m_dir) {
            case Direction::Up:    nextHeadPos.y -= SNAKE_SEGMENT_SIZE; break;
            case Direction::Down:  nextHeadPos.y += SNAKE_SEGMENT_SIZE; break;
            case Direction::Left:  nextHeadPos.x -= SNAKE_SEGMENT_SIZE; break;
            case Direction::Right: nextHeadPos.x += SNAKE_SEGMENT_SIZE; break;
            case Direction::None:  break;
        }
    segmentShape.setPosition(lerp(headPos, nextHeadPos, alpha));
    segmentShape.setFillColor(sf::Color::Green);
    m_window.draw(segmentShape);

    for (size_t i = 1; i < m_body.size(); ++i) {
        sf::Vector2f currentPos = m_body[i].getPosition();
        sf::Vector2f prevPos = m_body[i - 1].getPosition();
        segmentShape.setPosition(lerp(currentPos, prevPos, alpha));
        segmentShape.setFillColor(sf::Color(0, 150, 0));
        m_window.draw(segmentShape);
    }
}

const sf::Vector2f& Snake::GetHeadPosition() const {
    return m_body.front().getPosition();
}

const std::deque<sf::RectangleShape>& Snake::GetBody() const {
    return m_body;
}

bool Snake::checkCollision() const {
    const sf::Vector2f& headPos = m_body.front().getPosition();

    if (headPos.x < 0 || headPos.x >= WINDOW_WIDTH ||
        headPos.y < 0 || headPos.y >= WINDOW_HEIGHT) {
        return true;
    }

    for (auto it = std::next(m_body.begin()); it != m_body.end(); ++it) {
        if (headPos == it->getPosition()) {
            return true;
        }
    }

    return false;
}