void Player::interact(Block *block) {
    switch(block->getType()) {
    case Type::GROUND:
        mState      = State::Ground;
        if(block->getCenter().y < getCenter().y) {
            // if player jumps into ceiling
            setPosition(getPosition().x, block->getPosition().y + block->getSize().y);
            mVelocity.y *= -0.45f;
        }
        else {
            setPosition(getPosition().x, block->getPosition().y - getSize().y);
            mVelocity.y = 0.f;
        }
        break;

    case Type::SPRINGBOARD:
        springJump(block->getPeriod());
        break;

    case Type::SPIKES:
    case Type::SAWBLADE:
        die();
        break;

    case Type::COIN:
        scoreUp(block);
        break;

    default : break;
    }
}