www.pudn.com > openglbk.rar > bezsurf.c

/* 
 * 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 * Unpublished-- rights reserved under the copyright laws of the 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. 
 */ 
 
/*  bezsurf.c 
 *  This program renders a wireframe Bezier surface, 
 *  using two-dimensional evaluators. 
 */ 
#include  
#include  
 
GLfloat ctrlpoints[4][4][3] = { 
   {{-1.5, -1.5, 4.0}, {-0.5, -1.5, 2.0},  
    {0.5, -1.5, -1.0}, {1.5, -1.5, 2.0}},  
   {{-1.5, -0.5, 1.0}, {-0.5, -0.5, 3.0},  
    {0.5, -0.5, 0.0}, {1.5, -0.5, -1.0}},  
   {{-1.5, 0.5, 4.0}, {-0.5, 0.5, 0.0},  
    {0.5, 0.5, 3.0}, {1.5, 0.5, 4.0}},  
   {{-1.5, 1.5, -2.0}, {-0.5, 1.5, -2.0},  
    {0.5, 1.5, 0.0}, {1.5, 1.5, -1.0}} 
}; 
 
void display(void) 
{ 
   int i, j; 
 
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
   glColor3f(1.0, 1.0, 1.0); 
   glPushMatrix (); 
   glRotatef(85.0, 1.0, 1.0, 1.0); 
   for (j = 0; j <= 8; j++) { 
      glBegin(GL_LINE_STRIP); 
      for (i = 0; i <= 30; i++) 
         glEvalCoord2f((GLfloat)i/30.0, (GLfloat)j/8.0); 
      glEnd(); 
      glBegin(GL_LINE_STRIP); 
      for (i = 0; i <= 30; i++) 
         glEvalCoord2f((GLfloat)j/8.0, (GLfloat)i/30.0); 
      glEnd(); 
   } 
   glPopMatrix (); 
   glFlush(); 
} 
 
void init(void) 
{ 
   glClearColor (0.0, 0.0, 0.0, 0.0); 
   glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 
           0, 1, 12, 4, &ctrlpoints[0][0][0]); 
   glEnable(GL_MAP2_VERTEX_3); 
   glMapGrid2f(20, 0.0, 1.0, 20, 0.0, 1.0); 
   glEnable(GL_DEPTH_TEST); 
   glShadeModel(GL_FLAT); 
} 
 
void reshape(int w, int h) 
{ 
   glViewport(0, 0, (GLsizei) w, (GLsizei) h); 
   glMatrixMode(GL_PROJECTION); 
   glLoadIdentity(); 
   if (w <= h) 
      glOrtho(-4.0, 4.0, -4.0*(GLfloat)h/(GLfloat)w,  
              4.0*(GLfloat)h/(GLfloat)w, -4.0, 4.0); 
   else 
      glOrtho(-4.0*(GLfloat)w/(GLfloat)h,  
              4.0*(GLfloat)w/(GLfloat)h, -4.0, 4.0, -4.0, 4.0); 
   glMatrixMode(GL_MODELVIEW); 
   glLoadIdentity(); 
} 
 
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 | GLUT_DEPTH); 
   glutInitWindowSize (500, 500); 
   glutInitWindowPosition (100, 100); 
   glutCreateWindow (argv[0]); 
   init (); 
   glutDisplayFunc(display); 
   glutReshapeFunc(reshape); 
   glutKeyboardFunc(keyboard); 
   glutMainLoop(); 
   return 0; 
}