GLUT and gnuplot window not showing up at the same time

Question

I have the following functions whose objective is to display a GLUT window displaying a 3D object and a Gnuplot window to display a plot.

For that I use the Gnuplot-Iostream Interface. The plotting code is located inside a function as it will be updated when the user types on the keyboard.

The following code will only display the Gnuplot window after I close the GLUT window:

#include "gnuplot-iostream.h"
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

void displayGraph();
void displayGnuplot();
Gnuplot gp;

int main(int argc, char** argv) {

    displayGnuplot();

    glutInit(&argc,argv);
    glutInitWindowSize(1024, 1024);
    glutInitWindowPosition(1080,10);
    glutCreateWindow("Continuum Data");
    glutDisplayFunc(displayGraph);

    glutMainLoop();
}

void displayGraph(){
    /*
    Code to display in Glut window that will be updated
    */
}

void displayGnuplot(){

    bool displayGnuplot = true;
    gp << "set xrange [-2:2]\nset yrange [-2:2]\n";
    gp << "plot '-' with vectors title 'pts_A', '-' with vectors title 'pts_B'\n";
}

What works is declaring the Gnuplot instance inside the displayGraph function. Unfortunately this wont work for my case as each time the displayGraph function is called a new Gnuplot window is created whereas I just want the Gnuplot window updated.

I've also tried putting a condition around the creation of the Gnuplot window to no avail:

#include "gnuplot-iostream.h"
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

void displayGraph();
void displayGnuplot();
Gnuplot gp;

int main(int argc, char** argv) {

    displayGnuplot();

    glutInit(&argc,argv);
    glutInitWindowSize(1024, 1024);
    glutInitWindowPosition(1080,10);
    glutCreateWindow("Continuum Data");
    glutDisplayFunc(displayGraph);

    glutMainLoop();
}

void displayGraph(){
    /*
    Code to display in Glut window that will be updated
    */
}

void displayGnuplot(){

    if(!gnuplotExists){
        Gnuplot gp;
        gnuplotExists = true;
    }
    gp << "set xrange [-2:2]\nset yrange [-2:2]\n";
    gp << "plot '-' with vectors title 'pts_A', '-' with vectors title 'pts_B'\n";
}

I can see how my code was a bit confusing, I've updated it to separate the use of GLUT and Gnuplot. What I want is for the Gnuplot and GLUT windows to both appear at once. They don't really interact with each other. — Anthony Lethuillier, Dec 21 '17 at 20:30

score 0 · Accepted Answer · answered Dec 21 '17 at 23:59

I've found a solution using a different C++ interface to Gnuplot, namely gnuplot-cpp

#include "gnuplot_i.hpp" //Gnuplot class handles POSIX-Pipe-communikation with Gnuplot
#include <GL/glut.h>

void displayGraph();
void displayGnuplot();
Gnuplot g1("lines");

int main(int argc, char** argv) {

    displayGnuplot();

    glutInit(&argc,argv);
    glutInitWindowSize(1024, 1024);
    glutInitWindowPosition(1080,10);
    glutCreateWindow("Continuum Data");
    glutDisplayFunc(displayGraph);

    glutMainLoop();
}

void displayGraph(){

}

void displayGnuplot(){

    g1.set_title("Slopes\\nNew Line");
    g1.plot_slope(1.0,0.0,"y=x");
    g1.plot_slope(2.0,0.0,"y=2x");
    g1.plot_slope(-1.0,0.0,"y=-x");
    g1.unset_title();
    g1.showonscreen();
}

This solution works for me as it displays at the same time the GLUT and gnuplot window and both can be updated when the user issues commands.

GLUT and gnuplot window not showing up at the same time

1 Answers1