varray.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 * Unpublished-- rights reserved under the copyright laws of the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.
 */

/*
 *  varray.c
 *  This program demonstrates vertex arrays.
 */
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>

#ifdef GL_VERSION_1_1
#define POINTER 1
#define INTERLEAVED 2

#define DRAWARRAY 1
#define ARRAYELEMENT  2
#define DRAWELEMENTS 3

int setupMethod = POINTER;
int derefMethod = DRAWARRAY;

void setupPointers(void)
{
   static GLint vertices[] = {25, 25,
                       100, 325,
                       175, 25,
                       175, 325,
                       250, 25,
                       325, 325};
   static GLfloat colors[] = {1.0, 0.2, 0.2,
                       0.2, 0.2, 1.0,
                       0.8, 1.0, 0.2,
                       0.75, 0.75, 0.75,
                       0.35, 0.35, 0.35,
                       0.5, 0.5, 0.5};

   glEnableClientState (GL_VERTEX_ARRAY);
   glEnableClientState (GL_COLOR_ARRAY);

   glVertexPointer (2, GL_INT, 0, vertices);
   glColorPointer (3, GL_FLOAT, 0, colors);
}

void setupInterleave(void)
{
   static GLfloat intertwined[] =
      {1.0, 0.2, 1.0, 100.0, 100.0, 0.0,
       1.0, 0.2, 0.2, 0.0, 200.0, 0.0,
       1.0, 1.0, 0.2, 100.0, 300.0, 0.0,
       0.2, 1.0, 0.2, 200.0, 300.0, 0.0,
       0.2, 1.0, 1.0, 300.0, 200.0, 0.0,
       0.2, 0.2, 1.0, 200.0, 100.0, 0.0};
   
   glInterleavedArrays (GL_C3F_V3F, 0, intertwined);
}

void init(void) 
{
   glClearColor (0.0, 0.0, 0.0, 0.0);
   glShadeModel (GL_SMOOTH);
   setupPointers ();
}

void display(void)
{
   glClear (GL_COLOR_BUFFER_BIT);

   if (derefMethod == DRAWARRAY) 
      glDrawArrays (GL_TRIANGLES, 0, 6);
   else if (derefMethod == ARRAYELEMENT) {
      glBegin (GL_TRIANGLES);
      glArrayElement (2);
      glArrayElement (3);
      glArrayElement (5);
      glEnd ();
   }
   else if (derefMethod == DRAWELEMENTS) {
      GLuint indices[4] = {0, 1, 3, 4};

      glDrawElements (GL_POLYGON, 4, GL_UNSIGNED_INT, indices);
   }
   glFlush ();
}

void reshape (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
   gluOrtho2D (0.0, (GLdouble) w, 0.0, (GLdouble) h);
}

void mouse (int button, int state, int x, int y)
{
   switch (button) {
      case GLUT_LEFT_BUTTON:
         if (state == GLUT_DOWN) {
            if (setupMethod == POINTER) {
               setupMethod = INTERLEAVED;
               setupInterleave();
            }
            else if (setupMethod == INTERLEAVED) {
               setupMethod = POINTER;
               setupPointers();
            }
            glutPostRedisplay();
         }
         break;
      case GLUT_MIDDLE_BUTTON:
      case GLUT_RIGHT_BUTTON:
         if (state == GLUT_DOWN) {
            if (derefMethod == DRAWARRAY) 
               derefMethod = ARRAYELEMENT;
            else if (derefMethod == ARRAYELEMENT) 
               derefMethod = DRAWELEMENTS;
            else if (derefMethod == DRAWELEMENTS) 
               derefMethod = DRAWARRAY;
            glutPostRedisplay();
         }
         break;
      default:
         break;
   }
}

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

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize (350, 350); 
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init ();
   glutDisplayFunc(display); 
   glutReshapeFunc(reshape);
   glutMouseFunc(mouse);
   glutKeyboardFunc (keyboard);
   glutMainLoop();
   return 0;
}
#else
int main(int argc, char** argv)
{
    fprintf (stderr, "This program demonstrates a feature which is not in OpenGL Version 1.0.\n");
    fprintf (stderr, "If your implementation of OpenGL Version 1.0 has the right extensions,\n");
    fprintf (stderr, "you may be able to modify this program to make it run.\n");
    return 0;
}
#endif