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 * Unpublished-- rights reserved under the copyright laws of the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

/*
 *  lines.c
 *  This program demonstrates geometric primitives and
 *  their attributes.
 */
#include <GL/glut.h>
#include <stdlib.h>

#define drawOneLine(x1,y1,x2,y2)  glBegin(GL_LINES);  \
   glVertex2f ((x1),(y1)); glVertex2f ((x2),(y2)); glEnd();

void init(void) 
{
   glClearColor (0.0, 0.0, 0.0, 0.0);
   glShadeModel (GL_FLAT);
}

void display(void)
{
   int i;

   glClear (GL_COLOR_BUFFER_BIT);

/* select white for all lines  */
   glColor3f (1.0, 1.0, 1.0);

/* in 1st row, 3 lines, each with a different stipple  */
   glEnable (GL_LINE_STIPPLE);
   
   glLineStipple (1, 0x0101);  /*  dotted  */
   drawOneLine (50.0, 125.0, 150.0, 125.0);
   glLineStipple (1, 0x00FF);  /*  dashed  */
   drawOneLine (150.0, 125.0, 250.0, 125.0);
   glLineStipple (1, 0x1C47);  /*  dash/dot/dash  */
   drawOneLine (250.0, 125.0, 350.0, 125.0);

/* in 2nd row, 3 wide lines, each with different stipple */
   glLineWidth (5.0);
   glLineStipple (1, 0x0101);  /*  dotted  */
   drawOneLine (50.0, 100.0, 150.0, 100.0);
   glLineStipple (1, 0x00FF);  /*  dashed  */
   drawOneLine (150.0, 100.0, 250.0, 100.0);
   glLineStipple (1, 0x1C47);  /*  dash/dot/dash  */
   drawOneLine (250.0, 100.0, 350.0, 100.0);
   glLineWidth (1.0);

/* in 3rd row, 6 lines, with dash/dot/dash stipple  */
/* as part of a single connected line strip         */
   glLineStipple (1, 0x1C47);  /*  dash/dot/dash  */
   glBegin (GL_LINE_STRIP);
   for (i = 0; i < 7; i++)
      glVertex2f (50.0 + ((GLfloat) i * 50.0), 75.0);
   glEnd ();

/* in 4th row, 6 independent lines with same stipple  */
   for (i = 0; i < 6; i++) {
      drawOneLine (50.0 + ((GLfloat) i * 50.0), 50.0,
         50.0 + ((GLfloat)(i+1) * 50.0), 50.0);
   }

/* in 5th row, 1 line, with dash/dot/dash stipple    */
/* and a stipple repeat factor of 5                  */
   glLineStipple (5, 0x1C47);  /*  dash/dot/dash  */
   drawOneLine (50.0, 25.0, 350.0, 25.0);

   glDisable (GL_LINE_STIPPLE);
   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 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 (400, 150); 
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   init ();
   glutDisplayFunc(display); 
   glutReshapeFunc(reshape);
   glutKeyboardFunc(keyboard);
   glutMainLoop();
   return 0;
}