I've been reading up on OpenGL, but I'm particularly interested in swapping out bitmaps from a buffer onto a screen and visa versa.

My main function is as follows:

int main(int argc, char** argv)
{
  init_font();
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_SINGLE);
  glutInitWindowSize(500,500);
  glutInitWindowPosition(0,0);
  glutCreateWindow("Griddle");
  glutDisplayFunc(renderFunction);
  glutMainLoop();    
  return 0;
}

void renderFunction()
{
  glClearColor(0.0, 0.0, 0.0, 0.0);
  glClear(GL_COLOR_BUFFER_BIT);
  glColor3f(1.0, 1.0, 1.0);
  glFlush();
}

This opens a window with a black backgound.

My understanding is that I should define a Framebuffer:

glGenFramebuffers(1, &frameBufferID);

and then bind it:

glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);

Am I correct in thinking that anything drawn on the FBO is rendered on the screen?

How can I assign a 2D array to a buffer and then render it to the screen?

To get data from a bitmap to the screen, copy the data into a texture using glTexImage2D. Then draw that texture to the screen on a quad

To get the data from the buffer you can use glReadPixels

Thanks for the responses.

Here's what I have:

#include <GL/glut.h>
void display(void)
{
 glClear(GL_COLOR_BUFFER_BIT);
 glFlush();
}
int main(int argc, char** argv)
{
 glutInit(&argc, argv);
 glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
 glutInitWindowSize(600, 600);
 glutInitWindowPosition(100, 10);
 glutCreateWindow(argv[0]);
 glutDisplayFunc(display);
 glutMainLoop();
 return 0;
}

This produces a black window.

What I want is to be able to have a white block at the bottom of the window in which to draw text.

I also want to be able to draw lines and text in the black area as depicted in the attached image.

[attachment=24729:opengl.png]

I want both areas to be drawn to off screen and to be bit blitted onto the screen as needed, so I need 2 (or more) separate scratch areas to draw to.