2D Game Grid Model from C++ to QML

DenverCoder21

Hello guys, I'm fairly new to Qt/QML and currently try to create a little Snake game. For this, I implemented a C++ model of a game board which has a two-dimensional array containing the states of the respective cell (empty, snake, fruit). I'd like to practice exposing custom models from C++ to QML, please bear that in mind in your answers (as in please no QML-only answers), thank you. ;-)

The best approach to me seemed to have my game board class subclass QAbstractTableModel, which I did as best as I could.
My problem now is the next step when it comes to using it in QML. So far I only found examples using role names - but the cells of a row don't have role names, just a state. Also I've seen examples that use a QML TableView with handwritten TableColumns added - but I want QML to display how many columns ever my model has.

Here is my code so far:

board.h

#pragma once

#include <vector>

#include <QAbstractTableModel>

class board : public QAbstractTableModel
{
  Q_OBJECT

public:
  enum class state
  {
    empty,
    snake,
    fruit
  };

  board(int width, int height);

  state get_state(int x, int y) const;
  void  set_state(int x, int y, state state);

  int rowCount(const QModelIndex& parent = QModelIndex()) const;
  int columnCount(const QModelIndex& parent = QModelIndex()) const;
  QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const;

private:
  std::vector<std::vector<state>> m_board;
};

Q_DECLARE_METATYPE(board::state)

board.cpp

#include "board.h"

board::board(int width, int height) :
  m_board(width, std::vector<state>(height, state::empty))
{
}

board::state board::get_state(int x, int y) const
{
  return m_board.at(x).at(y);
}

void board::set_state(int x, int y, board::state state)
{
  m_board.at(x).at(y) = state;
}

int board::rowCount(const QModelIndex&) const
{
  return m_board.size();
}

int board::columnCount(const QModelIndex&) const
{
  return m_board.at(0).size();
}

QVariant board::data(const QModelIndex& index, int role) const
{
  if(!index.isValid())
    return QVariant();

  if(role != Qt::DisplayRole)
    return QVariant();

  return qVariantFromValue(get_state(index.row(), index.column()));
}

I haven't written anything in QML, yet. Am I on the right path? What would I need to do in QML?

Thanks a lot!

p3c0

@DenverCoder21

So far I only found examples using role names - but the cells of a row don't have role names, just a state

If they dont then there's no way to get data from model to the view. The view will look completely blank.
Well honestly I cant tell if this is the best idea to use a model. May be you have already thought of the updating the model for eg. how to update each cell when the snake moves.

Btw. did you look at this Snake game ? Sorry it's QML-only ;). But you can try to fit the logic into model.

DenverCoder21

I found a solution, please see my own answer in here.