OpenGLUT 0.6.3 development - OpenGLUT: surface.c File Reference
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# surface.c File Reference

## Detailed Description

This program draws a NURBS surface in the shape of a symmetrical hill.

    /* aux2glut conversion Copyright (c) Mark J. Kilgard, 1994, 1995 */

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     * Unpublished-- rights reserved under the copyright laws of the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

    #include <GL/openglut.h>
    #include <stdlib.h>

    GLfloat ctlpoints[4][4][3];
    int showPoints = 0;

    GLUnurbsObj *theNurb;

    /*
     *  Initializes the control points of the surface to a small hill.
     *  The control points range from -3 to +3 in x, y, and z
     */
    void init_surface(void)
    {
        int u, v;
        for (u = 0; u < 4; u++) {
        for (v = 0; v < 4; v++) {
            ctlpoints[u][v][0] = 2.0*((GLfloat)u - 1.5);
            ctlpoints[u][v][1] = 2.0*((GLfloat)v - 1.5);

            if ( (u == 1 || u == 2) && (v == 1 || v == 2))
            ctlpoints[u][v][2] = 7.0;
            else
            ctlpoints[u][v][2] = -3.0;
        }
        }
    }

    /*  Initialize material property and depth buffer.
     */
    void myinit(void)
    {
        GLfloat mat_diffuse[] = { 0.7, 0.7, 0.7, 1.0 };
        GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
        GLfloat mat_shininess[] = { 100.0 };

        glClearColor (0.0, 0.0, 0.0, 1.0);
        glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
        glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
        glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);

        glEnable(GL_LIGHTING);
        glEnable(GL_LIGHT0);
        glDepthFunc(GL_LESS);
        glEnable(GL_DEPTH_TEST);
        glEnable(GL_AUTO_NORMAL);
        glEnable(GL_NORMALIZE);

        init_surface();

        theNurb = gluNewNurbsRenderer();
        gluNurbsProperty(theNurb, GLU_SAMPLING_TOLERANCE, 25.0);
        gluNurbsProperty(theNurb, GLU_DISPLAY_MODE, GLU_FILL);

        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        glTranslatef (0.0, 0.0, -5.0);
    }

    void display(void)
    {
        GLfloat knots[8] = {0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0};
        int i, j;

        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glPushMatrix();
        glRotatef(330.0, 1.,0.,0.);
        glScalef (0.25, 0.25, 0.25);

        gluBeginSurface(theNurb);
        gluNurbsSurface(theNurb,
            8, knots,
            8, knots,
            4 * 3,
            3,
            &ctlpoints[0][0][0],
            4, 4,
            GL_MAP2_VERTEX_3);
        gluEndSurface(theNurb);

        if(showPoints) {
        glPointSize(5.0);
        glDisable(GL_LIGHTING);
        glColor3f(1.0, 1.0, 0.0);
        glBegin(GL_POINTS);
        for(i=0;i<4;i++) {
          for(j=0;j<4;j++) {
        glVertex3f(ctlpoints[i][j][0], ctlpoints[i][j][1], ctlpoints[i][j][2]);
          }
        }
        glEnd();
        glEnable(GL_LIGHTING);
        }

        glPopMatrix();
        glutSwapBuffers();
    }

    void reshape(int w, int h)
    {
        glViewport(0, 0, w, h);
        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective (45.0, (GLdouble)w/(GLdouble)h, 3.0, 8.0);

        glMatrixMode(GL_MODELVIEW);
    }

    void
    menu(int value)
    {
        switch (value) {
        case 0:
        case 1:
            showPoints = value;
        break;
        case 2:
            gluNurbsProperty(theNurb, GLU_DISPLAY_MODE, GLU_FILL);
        break;
        case 3:
            gluNurbsProperty(theNurb, GLU_DISPLAY_MODE, GLU_OUTLINE_POLYGON);
        break;
        }
        glutPostRedisplay();
    }

    int down = 0, lastx;

    /* ARGSUSED1 */
    void
    motion(int x, int y)
    {
        if (down) {
            glRotatef(lastx - x, 0, 1, 0);
            lastx = x;
            glutPostRedisplay();
        }
    }

    /* ARGSUSED3 */
    void
    mouse(int button, int state, int x, int y)
    {
        if (button == GLUT_LEFT_BUTTON) {
            if (state == GLUT_DOWN) {
                lastx = x;
                down = 1;
            } else {
                down = 0;
            }
        }
    }

    static void
    key(unsigned char k, int x, int y)
    {
      switch (k) {
      case 27:  /* Escape */
        exit(0);
        break;
      default:
        return;
      }
      glutPostRedisplay();
    }

    /* Main Loop */
    int
    main(int argc, char** argv)
    {
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGB);
        glutCreateWindow(argv[0]);
        myinit();
        glutReshapeFunc(reshape);
        glutDisplayFunc(display);
        glutCreateMenu(menu);
        glutAddMenuEntry("Show control points", 1);
        glutAddMenuEntry("Hide control points", 0);
        glutAddMenuEntry("Solid", 2);
        glutAddMenuEntry("Wireframe", 3);
        glutAttachMenu(GLUT_RIGHT_BUTTON);
        glutMouseFunc(mouse);
        glutMotionFunc(motion);
        glutKeyboardFunc(key);
        glutMainLoop();
        return 0;             /* ANSI C requires main to return int. */
    }

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