degrees, radians can't learn to use them

timob256

trying to draw a circle with vertices

#ifndef KRUG_QT_H
#define KRUG_QT_H

#include <QMainWindow>
#include <QDebug>
#include <QPainter>
#include <QPen>
#include <QFont>
#include <QtMath>
#include <QPointF>


class Krug_qt : public QMainWindow
{
    Q_OBJECT

public:
    Krug_qt(QWidget *parent = 0);
    ~Krug_qt();

    void fillVertexArray();

    float R;        // радиус
    int p;          // Количество продольных срезов. Number of longitudinal slices.
    int q;          // Количество широтных срезов. Number of latitudinal slices.
    int kol_toch;

    QVector<float> integerVector;

protected:
    void paintEvent(QPaintEvent *event);
//     void keyPressEvent(QKeyEvent *event);
};

#endif // KRUG_QT_H

#include "krug_qt.h"

Krug_qt::Krug_qt(QWidget *parent)
    : QMainWindow(parent)
{
    R = 90.0;
    q = 24;
    p = 24;

    kol_toch = 180;
}

Krug_qt::~Krug_qt()
{

}

void Krug_qt::fillVertexArray()
{
    float grad = 360.0/kol_toch;
    float grad_kol_toch = 0.0;
    // градусы*M_PI/180 = радианы
    int j;
    for (j = 0; j <= kol_toch; ++j){
        integerVector.append(R * cos(grad_kol_toch*M_PI/180.0));
        integerVector.append(R * sin(grad_kol_toch*M_PI/180.0));
        grad_kol_toch = grad_kol_toch + grad;
    }
}

void Krug_qt::paintEvent(QPaintEvent *event)
{
    integerVector.clear();
    QPainter painter(this);                                   // Создаём объект отрисовщика
    QPen pen_abris(Qt::black, 2, Qt::SolidLine, Qt::FlatCap); // кисть обрисовки (компаса)
    painter.setRenderHint(QPainter::Antialiasing);            // убираем резкие кубики
    painter.setPen(pen_abris);                                // Устанавливаем кисть обрисовки
    fillVertexArray();                                        // Набираем массив
    painter.translate(this->width()/2, this->height()/2);     // смещение отрисовки

    qDebug() << integerVector.size();

    int f = 0;
    for(int i =0; i<integerVector.size()/2; ++i)
    {
        i++; f++;
        painter.drawPoint(QPointF(integerVector[--i],integerVector[i]));
        qDebug() << "f :"<<f;
    }
}

I don't know what I'm doing wrong

here is the geometry of the points

void Krug_qt::fillVertexArray()
{
    float grad = 360.0/kol_toch;
    float grad_kol_toch = 0.0;
    // градусы*M_PI/180 = радианы
    int j;
    for (j = 0; j <= kol_toch; ++j){
        integerVector.append(R * cos(grad_kol_toch*M_PI/180.0));
        integerVector.append(R * sin(grad_kol_toch*M_PI/180.0));
        grad_kol_toch = grad_kol_toch + grad;
    }
}

and

qDebug() << integerVector.size();

int f = 0;
for(int i =0; i<integerVector.size()/2; ++i)
{
    i++; f++;
    painter.drawPoint(QPointF(integerVector[--i],integerVector[i]));
    qDebug() << "f :"<<f;
}

timob256

understood. it should have been like this

int f = 0; int tocka_1 = 0; int tocka_2 = 0;
   for(int i =0; i<kol_toch; ++i)
   {
       tocka_2 =  tocka_1+1;
       painter.drawPoint(QPointF(integerVector[tocka_1],integerVector[tocka_2]));
       tocka_1 = tocka_1 +2;
       qDebug() << "i :"<<i;
   }

mchinand

@timob256 said in degrees, radians can't learn to use them:

for(int i =0; i<integerVector.size()/2; ++i)
{
i++; f++;
painter.drawPoint(QPointF(integerVector[--i],integerVector[i]));
qDebug() << "f :"<<f;
}

You're not traversing all of integerVector.
One way to do it would be:

for(int i = 0; i < integerVector.size()/2; ++i) {
     f++;
     painter.drawPoint(QPointF(integerVector[2 * i], integerVector[2 * i + 1]));
     qDebug() << "f :" << f;
 }

Your first loop could also be simplified by using the loop variable in your equations that populate integerVector (which doesn't contain integers) and use grad in your loop-increment statement.

JonB

degrees, radians can't learn to use them

Radians are for mathematicians, maybe physicists. Degrees are for the rest of us :)