Raspbian 2 player chess game

[Quantum1982]

Sorry here is the code :
#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QImage>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);

QBrush greenBrush(Qt::green);
QBrush blueBrush(Qt::blue);
QPen outlinePen(Qt::black);
outlinePen.setWidth(2);

for (int i=0;i<8;i++)
    for (int j=0;j<8;j++)
        if ((i+j)%2==0)
        rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                   ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                   BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, blueBrush);
        else rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                        ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                        BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, greenBrush);


QString ChessPieces[12];

ChessPieces[0] = "C:/Users/User/Desktop/WhitePawn.jpg";
ChessPieces[1] = "C:/Users/User/Desktop/WhiteRook.jpg";
ChessPieces[2] = "C:/Users/User/Desktop/WhiteKnight.jpg";
ChessPieces[3] = "C:/Users/User/Desktop/WhiteBishop.jpg";
ChessPieces[4] = "C:/Users/User/Desktop/WhiteQueen.jpg";
ChessPieces[5] = "C:/Users/User/Desktop/WhiteKing.jpg";
ChessPieces[6] = "C:/Users/User/Desktop/BlackPawn.jpg";
ChessPieces[7] = "C:/Users/User/Desktop/BlackRook.jpg";
ChessPieces[8] = "C:/Users/User/Desktop/BlackKnight.jpg";
ChessPieces[9] = "C:/Users/User/Desktop/BlackBishop.jpg";
ChessPieces[10] = "C:/Users/User/Desktop/BlackQueen.jpg";
ChessPieces[11] = "C:/Users/User/Desktop/BlackKing.jpg";

QPixmap Pixmap("C:/Users/User/Desktop/WhiteQueen.jpg");
WhiteQueen = new QLabel(this);

WhiteQueen->setGeometry(50,50,100,100);
WhiteQueen->setPixmap(Pixmap);

}

MainWindow::~MainWindow()
{
delete ui;
}

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#define BOARD_X1 20
#define BOARD_Y1 20
#define SQUARE_WIDTH 50
#define SQUARE_HEIGHT 50

#include <QMainWindow>
#include <QGraphicsView>
#include <QGraphicsItem>
#include <QLabel>

class CChessBoard : public QGraphicsView
{
public:

};

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
QLabel *WhiteQueen;
MainWindow(QWidget *parent = nullptr);
~MainWindow();

private:
Ui::MainWindow *ui;
QGraphicsScene *scene;
QGraphicsRectItem *rectangle;
};
#endif // MAINWINDOW_H

[SGaist]

Are you doing anything else with rectangle ?

Since you are using the graphics view framework, why are you using QLabel for your chess pieces ?

[Quantum1982]

Well can I use an array of QImages instead ?

[SGaist]

QGraphicsPixmapItem

You really should take the time to explore the documentation.

[Quantum1982]

Yeah QGraphicsPixmapItem solves the problem

[Quantum1982]

I am having a problem loading multiple pixmaps ?

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QImage>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);

QBrush greenBrush(Qt::green);
QBrush blueBrush(Qt::blue);
QPen outlinePen(Qt::black);
outlinePen.setWidth(2);

for (int i=0;i<8;i++)
    for (int j=0;j<8;j++)
        if ((i+j)%2==0)
        rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                   ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                   BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, blueBrush);
        else rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                        ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                        BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, greenBrush);


QString ChessPieces[12];

ChessPieces[0] = "C:/Users/User/Desktop/WhitePawn.jpg";
ChessPieces[1] = "C:/Users/User/Desktop/WhiteRook.jpg";
ChessPieces[2] = "C:/Users/User/Desktop/WhiteKnight.jpg";
ChessPieces[3] = "C:/Users/User/Desktop/WhiteBishop.jpg";
ChessPieces[4] = "C:/Users/User/Desktop/WhiteQueen.jpg";
ChessPieces[5] = "C:/Users/User/Desktop/WhiteKing.jpg";
ChessPieces[6] = "C:/Users/User/Desktop/BlackPawn.jpg";
ChessPieces[7] = "C:/Users/User/Desktop/BlackRook.jpg";
ChessPieces[8] = "C:/Users/User/Desktop/BlackKnight.jpg";
ChessPieces[9] = "C:/Users/User/Desktop/BlackBishop.jpg";
ChessPieces[10] = "C:/Users/User/Desktop/BlackQueen.jpg";
ChessPieces[11] = "C:/Users/User/Desktop/BlackKing.jpg";

for (int i=0;i<8;i++)
    ChessPieceIndexes[i][1] = 0; // White Pawns
ChessPieceIndexes[0][0] = 1; // White Rook
ChessPieceIndexes[7][0] = 1; // White Rook

ChessPieceIndexes[1][0] = 2; // White Knight
ChessPieceIndexes[7][0] = 2; // White Knight

ChessPieceIndexes[2][0] = 3; // White Bishop
ChessPieceIndexes[6][0] = 3; // White Bishop

ChessPieceIndexes[3][0] = 4; // White Queen
ChessPieceIndexes[4][0] = 5; // White King


/*
WhiteQueen = new QLabel(this);

WhiteQueen->setGeometry(BOARD_X1+4*SQUARE_WIDTH,BOARD_Y1+4*SQUARE_HEIGHT,
                        BOARD_X1+4*SQUARE_WIDTH+SQUARE_WIDTH,BOARD_Y1+4*SQUARE_HEIGHT+SQUARE_HEIGHT);
WhiteQueen->setPixmap(Pixmap);
*/

QPixmap Pixmap(ChessPieces[0]); // White Pawn

for (int i=0;i<8;i++)
{
    QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
    item->setPos(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(7*SQUARE_HEIGHT));
    scene->addItem(item);
}
// White Rooks
Pixmap.load(ChessPieces[1]);
QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
item->setPos(BOARD_X1+(0*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
scene->addItem(item);

//QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
item->setPos(BOARD_X1+(7*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
scene->addItem(item);

// White Knights
Pixmap.load(ChessPieces[2]);
//QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
item->setPos(BOARD_X1+(1*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
scene->addItem(item);

}

MainWindow::~MainWindow()
{
delete ui;
}

[JonB]

@Quantum1982 said in Raspbian 2 player chess game:

Yeah QGraphicsPixmapItem solves the problem

Which is why I wrote earlier:

I'm not sure I would do this whole chess UI with widgets, probably a graphics scene with QGraphicsPixmapItems instead, but that's a whole different matter.

I am having a problem loading multiple pixmaps ?

I'm not following your code --- what is your problem?

[Quantum1982]

It's not adding the pixmapitems correctly. It adds the pawns but not the rooks ?

[JonB]

@Quantum1982
Check the return result from Pixmap.load(ChessPieces[1]);? And when developing code at least check the return result of every function which returns one, always, if only with a Q_ASSERT(false) in the failure case.

[SGaist]

Rather than using lists that does not allow you to properly reason about how your pieces are put on your chessboard, you should cleanup your code first.

Use proper naming for your variables. If you want to store the paths to your images in a single structure, use a QMap with a clear meaningful key using for example an enum.

Write your code in clear separate steps. Start by drawing the board, then put the pawns in place, then the king, queen, etc. Stop trying to make everything as compact as possible. You are losing time and not learning to do things properly. Write code that you and other people can understand.

[Quantum1982]

Ok. My debugger doesn't work or load. Are there settings that I need to configure ?

[Quantum1982]

When I put the pixmaps inside a loop, then it loads. But the other pieces don't ?

[JonB]

@Quantum1982
a. Debug your code. That's what developers do when things go wrong.
b. Deal with the warnings I see in the output window.

[Quantum1982]

My debugger doesn't load ?

[JonB]

@Quantum1982
a. So sort out your debugger. And if you cannot do that yourself we need more than "My debugger doesn't load". Any error messages? How do you know it does not load?

b. I didn't say you had to use the actual debugger. It's a luxury you should get working, but it's not a requirement for your issue(s). You could do lots of work yourself just by putting in judicious qDebug() statements. And by taking heed of my earlier suggestion to check return results and use Q_ASSERTs. So far your coding is progressing but you need to add such techniques. And it's not just that they solve issues, they also help you to understand what is going on, making future coding better. In the case of the QGraphicsScene::addItme warnings you don't even need any of this, just looking at your code should tell you.

[Quantum1982]

Ok.

I get the following error : Unable to create a debugging engine.

Also, is there a property in the QGraphicsView that I need to set to stop the last column and row from stretching to fit the output size ?

[Quantum1982]

I am now implementing the mouse clocking by the user.
I have this so far :

class MyGraphicsPixmapItem : public QGraphicsPixmapItem
{
public:
int SelectedSquareX, SelectedSquareY;
void mousePressEvent(QMouseEvent *eventPress);
};

What I am doing is I am getting the position of the mouse cursor when the user elft clicks, then I am storing the board coordinates in SelectedSquareX and SelectedSquareY.

But how should I declare the constructor ?

[jsulm]

@Quantum1982 said in Raspbian 2 player chess game:

But how should I declare the constructor ?

Like https://doc.qt.io/qt-5/qgraphicspixmapitem.html does maybe?

[Quantum1982]

Ok I will look into that.
Concerning the drawn chessboard I have the following :

As you can see the last column and row are being stretched to fir the graphicsview area.
Is there a setting that I need to configure that willl stop this ?

[Quantum1982]

Ok
I have made some progress.
This is what I have so far :

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#endif // MAINWINDOW_H

#define BOARD_X1 20
#define BOARD_Y1 20
#define SQUARE_WIDTH 50
#define SQUARE_HEIGHT 50

#define WHITE_PAWN 0
#define WHITE_ROOK 1
#define WHITE_KNIGHT 2
#define WHITE_BISHOP 3
#define WHITE_QUEEN 4
#define WHITE_KING 5

#define BLACK_PAWN 6
#define BLACK_ROOK 7
#define BLACK_KNIGHT 8
#define BLACK_BISHOP 9
#define BLACK_QUEEN 10
#define BLACK_KING 11

#include <QMainWindow>
#include <QGraphicsView>
#include <QGraphicsItem>
#include <QLabel>
#include <QMouseEvent>

class CChessBoard : public QGraphicsView
{
public:

};

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE



class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    QLabel *WhiteQueen;
    QString ChessPieces[12];

    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
    QGraphicsScene *scene;
    QGraphicsRectItem *rectangle;

    int ChessPieceIndexes[8][8]; // indexes to the image url
    void LoadPieceGraphics(void);
    void SetStartPosition(void);
};



class MyGraphicsPixmapItem : public QGraphicsPixmapItem
{
   public:
    int SelectedSquareX, SelectedSquareY;
    MyGraphicsPixmapItem(QGraphicsItem *parent = nullptr);
    void mousePressEvent(QMouseEvent *eventPress);
};

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QImage>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    scene = new QGraphicsScene(this);
    ui->graphicsView->setScene(scene);

   // MyGraphicsPixmapItem UserInput = MyGraphicsPixmapItem(QGraphicsItem *parent= nullptr);

    /* ///////////////////////////////////////////DRAW THE BOARD //////////////////////////////////////////////*/
    QBrush greenBrush(Qt::green);
    QBrush blueBrush(Qt::blue);
    QPen outlinePen(Qt::black);
    outlinePen.setWidth(2);

    for (int i=0;i<8;i++)
        for (int j=0;j<8;j++)
            if ((i+j)%2==0)
            rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                       ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                       BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, blueBrush);
            else rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                            ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                            BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, greenBrush);
   /* ///////////////////////////////////////////DRAW THE BOARD //////////////////////////////////////////////*/

    LoadPieceGraphics();
    SetStartPosition();

    /*
    WhiteQueen = new QLabel(this);
    QPixmap Pixmap(ChessPieces[4]); // White Queen

    WhiteQueen->setGeometry(BOARD_X1+4*SQUARE_WIDTH,BOARD_Y1+4*SQUARE_HEIGHT,
                            BOARD_X1+4*SQUARE_WIDTH+SQUARE_WIDTH,BOARD_Y1+4*SQUARE_HEIGHT+SQUARE_HEIGHT);
    WhiteQueen->setPixmap(Pixmap);
    WhiteQueen->setStyleSheet("background-color:rgba(0,0,255,0)");

    QLabel *BlackQueen = new QLabel(this);
    Pixmap.load(ChessPieces[10]); // Black Queen
    BlackQueen->setGeometry(BOARD_X1+4*SQUARE_WIDTH,BOARD_Y1+1*SQUARE_HEIGHT,
                            BOARD_X1+4*SQUARE_WIDTH+SQUARE_WIDTH,BOARD_Y1+1*SQUARE_HEIGHT+SQUARE_HEIGHT);
    BlackQueen->setPixmap(Pixmap);
    */

    QPixmap Pixmap(ChessPieces[0]); // White Pawn

    Pixmap.load(ChessPieces[0]);
    for (int i=0;i<8;i++)
    {
        QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
        item->setPos(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(7*SQUARE_HEIGHT));
        scene->addItem(item);
    }
    Pixmap.load(ChessPieces[1]);
    for (int i=0;i<8;i++)
    {
        QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
        item->setPos(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
        scene->addItem(item);
    }

    // White Rooks
    Pixmap.load(ChessPieces[1]);
    QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
    item->setPos(BOARD_X1+(0*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
    scene->addItem(item);

    Pixmap.load(ChessPieces[1]);
    //QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
    item->setPos(BOARD_X1+(7*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
    scene->addItem(item);

    // White Knights
    Pixmap.load(ChessPieces[2]);
    item->setPixmap(Pixmap);
    item->setPos(BOARD_X1+(1*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
    scene->addItem(item);

    item->setPos(BOARD_X1+(6*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
    scene->addItem(item);


    Pixmap.load(ChessPieces[6]); // Black Pawn
    for (int i=0;i<8;i++)
    {
        QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
        item->setPos(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(1*SQUARE_HEIGHT));
        scene->addItem(item);
    }

    Pixmap.load(ChessPieces[7]); // Black Rook
    item->setPixmap(Pixmap);
    item->setPos(BOARD_X1+(0*SQUARE_WIDTH),BOARD_Y1+(0*SQUARE_HEIGHT));
    scene->addItem(item);

    item->setPixmap(Pixmap);
    item->setPos(BOARD_X1+(7*SQUARE_WIDTH),BOARD_Y1+(0*SQUARE_HEIGHT));
    scene->addItem(item);

    Pixmap.load(ChessPieces[8]); // Black Knight
    item->setPixmap(Pixmap);
    item->setPos(BOARD_X1+(1*SQUARE_WIDTH),BOARD_Y1+(0*SQUARE_HEIGHT));
    scene->addItem(item);

    Pixmap.load(ChessPieces[9]); // Black Bishop
    item->setPixmap(Pixmap);
    item->setPos(BOARD_X1+(2*SQUARE_WIDTH),BOARD_Y1+(0*SQUARE_HEIGHT));
    scene->addItem(item);


}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::LoadPieceGraphics(void)
{
    ChessPieces[0] = "C:/Users/User/Desktop/WhitePawn.jpg";
    ChessPieces[1] = "C:/Users/User/Desktop/WhiteRook.jpg";
    ChessPieces[2] = "C:/Users/User/Desktop/WhiteKnight.jpg";
    ChessPieces[3] = "C:/Users/User/Desktop/WhiteBishop.jpg";
    ChessPieces[4] = "C:/Users/User/Desktop/WhiteQueen.jpg";
    ChessPieces[5] = "C:/Users/User/Desktop/WhiteKing.jpg";
    ChessPieces[6] = "C:/Users/User/Desktop/BlackPawn.jpg";
    ChessPieces[7] = "C:/Users/User/Desktop/BlackRook.jpg";
    ChessPieces[8] = "C:/Users/User/Desktop/BlackKnight.jpg";
    ChessPieces[9] = "C:/Users/User/Desktop/BlackBishop.jpg";
    ChessPieces[10] = "C:/Users/User/Desktop/BlackQueen.jpg";
    ChessPieces[11] = "C:/Users/User/Desktop/BlackKing.jpg";
}

void MainWindow::SetStartPosition(void)
{
    for (int i=0;i<8;i++)
        ChessPieceIndexes[i][1] = WHITE_PAWN; // White Pawns
    ChessPieceIndexes[0][0] = WHITE_ROOK; // White Rook
    ChessPieceIndexes[7][0] = WHITE_ROOK; // White Rook

    ChessPieceIndexes[1][0] = WHITE_KNIGHT; // White Knight
    ChessPieceIndexes[7][0] = WHITE_KNIGHT; // White Knight

    ChessPieceIndexes[2][0] = WHITE_BISHOP; // White Bishop
    ChessPieceIndexes[6][0] = WHITE_BISHOP; // White Bishop

    ChessPieceIndexes[3][0] = WHITE_QUEEN; // White Queen
    ChessPieceIndexes[4][0] = WHITE_KING; // White King

    for (int i=0;i<8;i++)
        ChessPieceIndexes[i][6] = BLACK_PAWN; // Black Pawns
    ChessPieceIndexes[0][7] = BLACK_ROOK; // Black Rook
    ChessPieceIndexes[7][7] = BLACK_ROOK; // Black Rook

    ChessPieceIndexes[1][7] = BLACK_KNIGHT; // Black Knight
    ChessPieceIndexes[7][7] = BLACK_KNIGHT; // Black Knight

    ChessPieceIndexes[2][7] = BLACK_BISHOP; // Black Bishop
    ChessPieceIndexes[6][7] = BLACK_BISHOP; // Black Bishop

    ChessPieceIndexes[3][7] = BLACK_QUEEN; // Black Queen
    ChessPieceIndexes[4][7] = BLACK_KING; // Black King

}


void MyGraphicsPixmapItem::mousePressEvent(QMouseEvent *eventPress)
{
    SelectedSquareX = eventPress->pos().x();
    SelectedSquareY = eventPress->pos().y();

}

[enter image description here][1]


  [1]: https://i.stack.imgur.com/XgstN.jpg

There are 3 issues which need clarification :

1. How do I stop the streching of the last column and row of the chess board ?

2. How do I make the chess pieces transparent ?

3. How do I implement the mouse click event so that a square gets highlighted when the user presses the left mouse button ?