How to stop an object of QGraphicsObjcet without using animation? - c++

Question

In this program I have a class inheriting of QGraphicsObject. This object (mario) go forward, go back and jump. For this jobs I changed mario's coordinate. But I have a problem. I want it to stop when collide with bricks. While I don't use of QPropertyAnimation how to stop this item.
extern mario* _mario=new mario;
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent)
{
size_of_plane_y=600;
size_of_plane_x=2000;
view=new QGraphicsView;
scene=new QGraphicsScene;
rec=new QGraphicsRectItem;
setCentralWidget(view);
view->setScene(scene);
scene->setSceneRect(0,0,size_of_plane_x,size_of_plane_y);
scene->addRect(scene->sceneRect());
x_scene=0;
y_scene=0;
int tmpb=8*30+120+10*30+120;
int tmpb2=10*30+120+8*30+120;
int firstb=100;
int firstb2=100+8*30+120;
for(int i=0;i<3;i++)
{
_brick=new brick(0,firstb,size_of_plane_y-180);
scene->addItem(_brick);
_brick2=new brick2(0,firstb2,size_of_plane_y-180);
scene->addItem(_brick2);
firstb+=tmpb;
firstb2+=tmpb2;
}
timer1=new QTimer(this);
timer1->setInterval(500);
connect(timer1,SIGNAL(timeout()),this,SLOT(up()));
};
void MainWindow::keyPressEvent(QKeyEvent *k)
{
switch (k->key())
{
case Qt::Key_J:
{
forward();
break;
}
case Qt::Key_Z:
{
timer1->start();
break;
}
case Qt::Key_F:
{
back();
break;
}
default:
break;
}
}
void MainWindow::forward()
{
if(ismovepossible(_mario->pos().x()+50,_mario->pos().y())==true)
{
_mario->setX(_mario->pos().x()+50);
scene->setSceneRect(x_scene+40,y_scene,size_of_plane_x,size_of_plane_y);
x_scene+=40;
}
}
void MainWindow::up()
{
static bool flag=0;
if(!flag)
{
if(ismovepossible(_mario->pos().x(),_mario->pos().y()-90)==true)
{
_mario->setY(_mario->pos().y()-90);
flag=1;
}
}
else
{
if(ismovepossible(_mario->pos().x(),_mario->pos().y()-90)==true)
{
_mario->setY(_mario->pos().y()+90);
timer1->stop();
flag=0;
}
}
}
void MainWindow::back()
{
if(ismovepossible(_mario->pos().x()-50,_mario->pos().y())==true)
{
_mario->setX(_mario->pos().x()-50);
scene->setSceneRect(x_scene-50,y_scene,size_of_plane_x,size_of_plane_y);
x_scene-=50;
}
}
////////////////edit
void MainWindow::projectile()//when user press Z and J simultaneity
{
static bool flag=0;
if(!flag)
{
if(ismovepossible(_mario->pos().x()+50,_mario->pos().y()-90)==true)
{
_mario->setY(_mario->pos().y()-90);
_mario->setX(_mario->pos().x()+50);
scene->setSceneRect(x_scene+50,y_scene,size_of_plane_x,size_of_plane_y);
x_scene-=50;
text->setPos(x_scene+200,10);
flag=1;
}
}
else
{
if(ismovepossible(_mario->pos().x(),_mario->pos().y()+90)==true)
{
_mario->setY(_mario->pos().y()+90);
timer2->stop();
flag=0;
}
}
}
/////////////////////add function
bool MainWindow::ismovepossible(int x, int y)
{
int dis_b=10*30+120+120;
int dis_b2=4*30+120+8*30+120;//8*30+120+120;
int firstb=100;
int endb=/*firstb*/100+8*30;
int firstb2=/*endb*/100+8*30+120;
int endb2=/*firstb2*/100+8*30+120+4*30;
int firstb3=/*endb2*/100+8*30+120+4*30+2*30;
int endb3=/*firstb3*/100+8*30+120+4*30+2*30+4*30;
int dis_b3=120+8*30+120+4*30+2*30;
if(y>size_of_plane_y-60 && y<=size_of_plane_y)
{
return false;
}
while(endb<size_of_plane_x)
{
if((y>size_of_plane_y-180 && y<size_of_plane_y-180+30)&&(x>firstb && x<endb))
{
return false;
}
else
{
firstb+=dis_b;
endb+=firstb;
}
}
while(endb2<size_of_plane_x)
{
if((y>size_of_plane_y-180 && y<size_of_plane_y-180+30)&&(x>firstb2 && x<endb2))
{
return false;
}
else
{
firstb2+=dis_b2;
endb2+=firstb2;
}
}
while(endb3<size_of_plane_x)
{
if((y>size_of_plane_y-180 && y<size_of_plane_y-180+30)&&(x>firstb3 && x<endb3))
{
return false;
}
else
{
firstb3+=dis_b3;
endb3+=firstb3;
}
}
return true;
}
class brick : public QGraphicsObject
{
Q_OBJECT
public:
explicit brick(QGraphicsItem *parent = 0,int x=100,int y=600-180);
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
QRectF boundingRect()const;
public slots:
void collision();
private:
int size_of_plane_y;
int start_x;
int start_y;
int size_brick;
};
brick::brick(QGraphicsItem *parent, int x, int y) : QGraphicsObject(parent)
{
size_of_plane_y=600;
start_x=x;
start_y=y;
size_brick=30;
connect(_mario,SIGNAL(xChanged()),this,SLOT(collision()));
connect(_mario,SIGNAL(yChanged()),this,SLOT(collision()));
}
void brick::collision()
{
if(this->collidesWithItem(_mario))
{
qDebug()<<"collision";
//what write here for stopping super mario?
}
}

Answer 1

I think you should modify your algorithm. The main problem here is you move mario before checking if there is a brick.
You move mario, you emit the signal xChanged() or yChanged(), check if you're on a brick or not ? Then you have to go back to the previous location ?
Since you know where you put your bricks, you can do something more like this:
void MainWindow::forward()
{
if(moveIsPossible(xDest, yDest))
{
_mario->setX(...);
[...]
}
In the moveIsPossible(xDest, yDest), you put the tuple (X,Y) of the future location, it returns true if you have no brick, no wall, no whatever you want, false otherwise.
Seeing your code, I just want to draw your attention on many thing:
Try to use const variable to put any configuration variable such as board size, brick size, etc ...
Try to create specific classes for specific function. forward(), back(), etc.. have not to be implemented in the mainwindow class.