Keep the gluInit Window Open

Question

//OpenGL functions, open a window and initialize

void display(void)

{

glClearColor(0.0f, 1.0f, 0.0f, 1.0f);

glClear(GL_COLOR_BUFFER_BIT);

glLoadIdentity();

glBegin(GL_LINES);

I = 0.;

do

{

	glVertex3d(PLOTX[I], PLOTY[I], PLOTZ[I]);

	glVertex3d(PLOTX[I + 1], PLOTY[I + 1], PLOTZ[I + 1]);

	++I;

	//output the values to the plot routines in OpenGL

	cout << "Output of values to OpenGL Plot routines, I" << " " << PLOTX[I] << " " << PLOTY[I] << " " << PLOTZ[I] << " " << I << "\n";

	cout << "Output of values to OpenGL Plot routines, I+1" << " " << PLOTX[I] << " " << PLOTY[I] << " " << PLOTZ[I] << " " << I + 1 << "\n";

} while (I <= INOW);

glEnd;

//glFlush();

}

//rename glutInit as one already in library, to eliminate "already has a body"

void initWindow(int* argcp, char** argv)

{

glutInit(argcp, argv);

glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH);

glutInitWindowPosition(100, 200);

glutInitWindowSize(800, 700);

glutCreateWindow("This is a window title");

glutDisplayFunc(display);

glutIdleFunc(display);

//glutMainLoop();

glFlush();

}

int main(int argcp, char** argv)

.

.

.

{

Running the above OpenGL sequence with graphics output to a window that was created with glutInit. Before I can view the output to the window, it immediately closes. How can I keep it open until finished in OpenGL and glutInit? Sid Kraft

Answer 1

Hi @Sid Kraft ,

The window closes because glutMainLoop() is commented out. That function keeps GLUT processing window events and calls the display function you registered.

I would call it from main after initializing the window:

int main(int argc, char** argv)
{
    initWindow(&argc, argv);
    glutMainLoop();
    return 0;
}

Also change:

glEnd;

to:

glEnd();

The parentheses are required to call the function, as explained in Microsoft’s documentation for compiler warning C4551.

With those changes, the window should remain open and GLUT can call display(). If it stays open but only shows the green background, that would be a separate drawing or coordinate issue.

If this helps resolve your issue, I would appreciate it if you could follow this guidance. It may also help others who encounter the same problem. Thank you.

Answer 2

We are currently working the issue and will provide an update soon. Thank you for your patience.