OpenGL /GLUT Creating window after mainEventLoop() - c++

Question

I am developing a game in OpenGL/GLUT and I need to open a new window to show the score when the game is won.
In order to do this, i will call glutCreateWindow() and register the callbacks after calling mainEventLoop().
Is there a problem with this ? How should I do it properly ?

Answer 1

Is there a problem with this?
Yes.
Why don't you simply draw the results in the same window as the game?
Why are you using GLUT in the first place? It's not a very good framework for games. Better use GLFW or SDL.
How should I do it properly ?
By adding a small GUI system to your engine, that allows you to overlay the screen with stats (like a HUD) and a score screen.

Answer 2

You will need two display callback functions, display( ) and display2( ) for each window plus window = glutCreateWindow("Window 1"); and window2 = glutCreateWindow("Window 2");.
Code example :
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <GL/glut.h>
int window2 = 0, window = 0, width = 400, height = 400;
void display(void)
{
glClearColor(0.0, 1.0, 1.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
glLoadIdentity();
printf("display1\n");
glFlush();
}
void display2(void)
{
glClearColor(1.0, 0.0, 0.0, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
glLoadIdentity();
printf("display2\n");
glFlush();
}
void reshape (int w, int h)
{
glViewport(0,0,(GLsizei)w,(GLsizei)h);
glutPostRedisplay();
}
int main(int argc, char **argv)
{
// Initialization stuff
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGB);
glutInitWindowSize(width, height);
// Create window main
window = glutCreateWindow("Window 1");
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutInitWindowPosition(100,100);
// Create second window
window2 = glutCreateWindow("Window 2");
glutDisplayFunc(display2);
glutReshapeFunc(reshape);
// Enter Glut Main Loop and wait for events
glutMainLoop();
return 0;
}