   basic gluLookAt questions..
  The source below is just a sample code that I got to play around with.. the gluLookAt function is put in the reshape function.. but is the reshape function loaded when the program runs aswell? what if I want to have a button that changes the view by calling gluLookAt, wouldnt this view be changed if I resized the window? /* * Copyright (c) 1993-1997, Silicon Graphics, Inc. * ALL RIGHTS RESERVED * Permission to use, copy, modify, and distribute this software for * any purpose and without fee is hereby granted, provided that the above * copyright notice appear in all copies and that both the copyright notice * and this permission notice appear in supporting documentation, and that * the name of Silicon Graphics, Inc. not be used in advertising * or publicity pertaining to distribution of the software without specific, * written prior permission. * * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE. * * US Government Users Restricted Rights * Use, duplication, or disclosure by the Government is subject to * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph * (c)(1)(ii) of the Rights in Technical Data and Computer Software * clause at DFARS 252.227-7013 and/or in similar or successor * clauses in the FAR or the DOD or NASA FAR Supplement. * Unpublished-- rights reserved under the copyright laws of the * United States.  Contractor/manufacturer is Silicon Graphics, * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311. * * OpenGL(R) is a registered trademark of Silicon Graphics, Inc. *//* *  planet.c *  This program shows how to composite modeling transformations *  to draw translated and rotated models. *  Interaction:  pressing the d D and y Y keys (day and year) *  alters the rotation of the planet around the sun. *  ESC key exits * *  modified smr may 03 - animate with stop s and Start S *  modified smr april 08 to test for single buffer and translates */#include <stdio.h>#include <GL/glut.h>#include <stdlib.h>static int year = 0, day = 0;void init(void){   glClearColor (0.0, 0.0, 0.0, 0.0);   glEnable(GL_DEPTH_TEST); // comment this out and see what happens.}void animate(void){  day = (day + 5) % 360;  year = (year + 1) % 360;  glutPostRedisplay();}void display(void){   glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);   glPushMatrix();glColor3f (1.0, 1.0, 1.0);glutSolidSphere(1.0, 20, 16);   /* draw sun */glRotatef ((GLfloat) year, 0.0, 1.0, 0.0);glTranslatef (-2.0, 0.0, 0.0); // try -2 on the x and note starting point of planetglRotatef ((GLfloat) day, 0.0, 1.0, 0.0);glColor3f (1.0, 1.0, 0.0);glutWireSphere(0.2, 10, 8);    /* draw smaller planet */   glPopMatrix();   glutSwapBuffers();   glFlush();}void reshape (int w, int h){   glViewport (0, 0, (GLsizei) w, (GLsizei) h);   glMatrixMode (GL_PROJECTION);   glLoadIdentity ();   gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);   glMatrixMode(GL_MODELVIEW);   glLoadIdentity();   gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);   //glTranslatef (0.0, 0.0, -3.0); // try the lookat or this. try values of 1.0 as well}void keyboard (unsigned char key, int x, int y){   switch (key) { case 'd':    day = (day + 10) % 360;    glutPostRedisplay();    break; case 'D':    day = (day - 10) % 360;    glutPostRedisplay();    break; case 'y':    year = (year + 5) % 360;    glutPostRedisplay();    break; case 'Y':    year = (year - 5) % 360;    glutPostRedisplay();    break; case 's': glutIdleFunc(NULL);    break; case 'S': glutIdleFunc(animate);    break; case 27:    exit(0);    break; default:    break;   }}int main(int argc, char** argv){   glutInit(&argc, argv);   glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);   //glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);   glutInitWindowSize (500, 500);   glutInitWindowPosition (100, 100);   glutCreateWindow (argv[0]);   init ();   glutDisplayFunc(display);   glutReshapeFunc(reshape);   glutKeyboardFunc(keyboard);   glutMainLoop();   return 0;}
Quote:but is the reshape function loaded when the program runs aswell?documentation: where the facts come from.Quote:what if I want to have a button that changes the view by calling gluLookAt, wouldnt this view be changed if I resized the window?Yes.   