mywidget.cpp

#include "myglwidget.h"

#include <QOpenGLContext>
#include <QOpenGLFunctions>
#include <QtMath>
#include <QDebug>

MyGlWidget::MyGlWidget(QWidget *parent) : QOpenGLWidget(parent)
{

}

void MyGlWidget::initializeGL()
{
    QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
    f->glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    f->glClearDepthf(1.0f);
    f->glEnable(GL_DEPTH_TEST);
    f->glDepthFunc(GL_LEQUAL);
}

void MyGlWidget::resizeGL(int w, int h)
{
    QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
    f->glViewport(0, 0, w, h);
    qDebug() <<w<<h;
    this->w = w;
    this->h = h;

    //   //setup the projection and switch to model view for transformations
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-1, 1, -1, 1, -1, 1);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}
void print_bitmap_string(/*void* font,*/ char* s)
{

      while (*s) {
         glutBitmapCharacter( GLUT_BITMAP_HELVETICA_18, *s);
         s++;
      }

}
void MyGlWidget::paintGL()
{
    QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
    f->glClear (GL_COLOR_BUFFER_BIT);
    f->glClear(GL_DEPTH_BUFFER_BIT);

    glLoadIdentity();
    glColor3f(0, 1, 0);
    glLineWidth(2);


    glBegin(GL_LINES);
    for (int i = 1; i < w; i += 10) {
        double x1 = i;
        double y1 = 0;
        double x2 = i;
        double y2 = h;

        x1 = 2*x1 / w - 1;
        y1 = 2*y1 / h - 1;

        x2 = 2*x2 / w - 1;
        y2 = 2*y2 / h - 1;

        glVertex2f(x1, y1);
        glVertex2f(x2, y2);
    }
    glEnd();

    {
       char* bitmap_font_names[7] = {"This is my firs text"};

       GLfloat x, y, ystep, yild, stroke_scale;

       /* Draw the strings, according to the current mode and font. */
       glTranslatef(0.5,-1.0,0);
       glColor4f(1.0, 1.0, 0.0, 0.0);
       x = -225.0;
       y = 70.0;
       ystep  = 100.0;
       yild   = 20.0;
          glRasterPos2f(-150, y+1.25*yild);
         print_bitmap_string(bitmap_font_names[0]);


    }


    f->glFlush ();
}