SGI Developer Toolbox 6.1/SGI Developer Toolbox 6.1 - Disc 1.iso/toolbox/src/exampleCode/opengl/GLUT/progs/examples/oclip.c

C/C++ Source or Header | 1996-11-11 | 5.5 KB | 204 lines

/* Copyright (c) Mark J. Kilgard, 1994. */

/**
 * (c) Copyright 1993, 1994, 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 * Unpublished-- rights reserved under the copyright laws of the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(TM) is a trademark of Silicon Graphics, Inc.
 */
/*----------------------------------------------------------------------------
 *
 * oclip.c : openGL (motif) example showing how to use arbitrary clipping plane.
 *
 * Author : Yusuf Attarwala
 *          SGI - Applications
 * Date   : Mar 93
 *
 *    note : the main intent of this program is to demo the arbitrary
 *           clipping functionality, hence the rendering is kept
 *           simple (wireframe) and only one clipping plane is used.
 *
 *    press  left   button to move object
 *           right  button to move clipping plane
 *
 *
 *---------------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>

#include <GL/glut.h>

/* function declarations */

void
    drawScene(void),
    setMatrix(void),
    animateClipPlane(void),
    animation(void),
    resize(int w, int h),
    keyboard(unsigned char c, int x, int y);


/* global variables */

float         ax,ay,az;             /* angles for animation */
GLUquadricObj *quadObj;             /* used in drawscene */
GLdouble planeEqn[] = {0.707,0.707,0.0,0.0};   /* initial clipping plane eqn */

int count = 0;
int clip_count = 0;

void
menu(int choice)
{
        switch (choice) {
        case 1 :
            count = 90;
            glutIdleFunc(animation);
            break;
        case 2 :
            animateClipPlane();
            break;
        }
}

int
main(int argc, char** argv)
{
    glutInit(&argc, argv);

    quadObj = gluNewQuadric ();   /* this will be used in drawScene */
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE);
    glutCreateWindow("Arbitrary clip plane");

    ax = 10.0;
    ay = -10.0;
    az = 0.0;

    glutDisplayFunc(drawScene);
    glutReshapeFunc(resize);
    glutKeyboardFunc(keyboard);
    glutCreateMenu(menu);
    glutAddMenuEntry("Rotate", 1);
    glutAddMenuEntry("Move clip plane", 2);
    glutAttachMenu(GLUT_RIGHT_BUTTON);
    glutMainLoop();
    return 0;             /* ANSI C requires main to return int. */
}

void
drawScene(void)
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glClear(GL_COLOR_BUFFER_BIT);

    glPushMatrix();
    gluQuadricDrawStyle (quadObj, GLU_LINE);
    glColor3f (1.0, 1.0, 0.0);
    glRotatef (ax,1.0,0.0,0.0);
    glRotatef (-ay,0.0, 1.0, 0.0);

    glClipPlane(GL_CLIP_PLANE0,planeEqn);      /* define clipping plane */
    glEnable(GL_CLIP_PLANE0);                  /* and enable it */

    gluCylinder (quadObj, 2.0,5.0,10.0,20,8);  /* draw a cone */

    glDisable(GL_CLIP_PLANE0);
    glPopMatrix();

    glutSwapBuffers();
}

void
setMatrix(void)
{
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-15.0,15.0,-15.0,15.0,-10.0,10.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void
animation(void)
{
   if(count) {
        ax += 5.0;
        ay -= 2.0;
        az += 5.0;
        if (ax >= 360)  ax = 0.0;
        if (ay <= -360) ay = 0.0;
        if (az >= 360)  az = 0.0;
        glutPostRedisplay();
        count--;
    }
    if(clip_count) {
    static int sign = 1;

        planeEqn[3] += sign*0.5;
        if (planeEqn[3] > 4.0) sign = -1;
        else if (planeEqn[3] < -4.0) sign = 1;
        glutPostRedisplay();
        clip_count--;
    }
    if(count <= 0 && clip_count <= 0) glutIdleFunc(NULL);
}

void
animateClipPlane(void)
{
    clip_count = 5;
    glutIdleFunc(animation);
}

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

void
resize(int w, int h)
{
    glViewport(0, 0, w, h);
    setMatrix();
}