list.c

OpenGL学习资料

/*
 * Copyright (c) 1993-1999, 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 * Unpublished-- rights reserved under the copyright laws of the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.
 */

/*
 *  list.c
 *  This program demonstrates how to make and execute a 
 *  display list.  Note that attributes, such as current 
 *  color and matrix, are changed.
 */
#include <GL/glut.h>
#include <stdlib.h>

GLuint listName;

static void init (void)
{
   listName = glGenLists (1);
   glNewList (listName, GL_COMPILE);
      glColor3f (1.0, 0.0, 0.0);  /*  current color red  */
      glBegin (GL_TRIANGLES);
      glVertex2f (0.0, 0.0);
      glVertex2f (1.0, 0.0);
      glVertex2f (0.0, 1.0);
      glEnd ();
      glTranslatef (1.5, 0.0, 0.0); /*  move position  */
   glEndList ();
   glShadeModel (GL_FLAT);
}

static void drawLine (void)
{
   glBegin (GL_LINES);
   glVertex2f (0.0, 0.5);
   glVertex2f (15.0, 0.5);
   glEnd ();
}

void display(void)
{
   GLuint i;

   glClear (GL_COLOR_BUFFER_BIT);
   glColor3f (0.0, 1.0, 0.0);  /*  current color green  */
   for (i = 0; i < 10; i++)    /*  draw 10 triangles    */
      glCallList (listName);
   drawLine ();  /*  is this line green?  NO!  */
                 /*  where is the line drawn?  */
   glFlush ();
}

void reshape(int w, int h)
{
   glViewport(0, 0, w, h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   if (w <= h) 
      gluOrtho2D (0.0, 2.0, -0.5 * (GLfloat) h/(GLfloat) w, 
         1.5 * (GLfloat) h/(GLfloat) w);
   else 
      gluOrtho2D (0.0, 2.0 * (GLfloat) w/(GLfloat) h, -0.5, 1.5); 
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
   switch (key) {
      case 27:
         exit(0);
         break;
   }
}

/*  Main Loop
 *  Open window with initial window size, title bar, 
 *  RGBA display mode, and handle input events.
 */
int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize(650, 50);
   glutCreateWindow(argv[0]);
   init ();
   glutReshapeFunc (reshape);
   glutDisplayFunc (display);
   glutKeyboardFunc (keyboard);
   glutMainLoop();
   return 0;
}