src/redbook/trim.c

   1 /*
   2  * Copyright (c) 1993-1997, Silicon Graphics, Inc.
   3  * ALL RIGHTS RESERVED
   4  * Permission to use, copy, modify, and distribute this software for
   5  * any purpose and without fee is hereby granted, provided that the above
   6  * copyright notice appear in all copies and that both the copyright notice
   7  * and this permission notice appear in supporting documentation, and that
   8  * the name of Silicon Graphics, Inc. not be used in advertising
   9  * or publicity pertaining to distribution of the software without specific,
  10  * written prior permission.
  11  *
  12  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
  13  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  14  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  15  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  16  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  17  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
  18  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
  19  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
  20  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
  21  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
  22  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
  23  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  * US Government Users Restricted Rights
  26  * Use, duplication, or disclosure by the Government is subject to
  27  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  28  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  29  * clause at DFARS 252.227-7013 and/or in similar or successor
  30  * clauses in the FAR or the DOD or NASA FAR Supplement.
  31  * Unpublished-- rights reserved under the copyright laws of the
  32  * United States.  Contractor/manufacturer is Silicon Graphics,
  33  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
  34  *
  35  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  36  */
  37
  38 /*
  39  *  trim.c
  40  *  This program draws a NURBS surface in the shape of a
  41  *  symmetrical hill, using both a NURBS curve and pwl
  42  *  (piecewise linear) curve to trim part of the surface.
  43  */
  44 #include <stdlib.h>
  45 #include "glut_wrap.h"
  46 #include <stdio.h>
  47
  48
  49 GLfloat ctlpoints[4][4][3];
  50
  51 GLUnurbsObj *theNurb;
  52
  53 /*
  54  *  Initializes the control points of the surface to a small hill.
  55  *  The control points range from -3 to +3 in x, y, and z
  56  */
  57 static void init_surface(void)
  58 {
  59    int u, v;
  60    for (u = 0; u < 4; u++) {
  61       for (v = 0; v < 4; v++) {
  62          ctlpoints[u][v][0] = 2.0*((GLfloat)u - 1.5);
  63          ctlpoints[u][v][1] = 2.0*((GLfloat)v - 1.5);
  64
  65          if ( (u == 1 || u == 2) && (v == 1 || v == 2))
  66             ctlpoints[u][v][2] = 3.0;
  67          else
  68             ctlpoints[u][v][2] = -3.0;
  69       }
  70    }
  71 }
  72
  73 static void GLAPIENTRY nurbsError(GLenum errorCode)
  74 {
  75    const GLubyte *estring;
  76
  77    estring = gluErrorString(errorCode);
  78    fprintf (stderr, "Nurbs Error: %s\n", (char *) estring);
  79    exit (0);
  80 }
  81
  82 /*  Initialize material property and depth buffer.
  83  */
  84 static void init(void)
  85 {
  86    GLfloat mat_diffuse[] = { 0.7, 0.7, 0.7, 1.0 };
  87    GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };
  88    GLfloat mat_shininess[] = { 100.0 };
  89
  90    glClearColor (0.0, 0.0, 0.0, 0.0);
  91    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
  92    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
  93    glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
  94
  95    glEnable(GL_LIGHTING);
  96    glEnable(GL_LIGHT0);
  97    glEnable(GL_DEPTH_TEST);
  98    glEnable(GL_AUTO_NORMAL);
  99    glEnable(GL_NORMALIZE);
 100
 101    init_surface();
 102
 103    theNurb = gluNewNurbsRenderer();
 104    gluNurbsProperty(theNurb, GLU_SAMPLING_TOLERANCE, 25.0);
 105    gluNurbsProperty(theNurb, GLU_DISPLAY_MODE, GLU_FILL);
 106    gluNurbsCallback(theNurb, GLU_ERROR, nurbsError);
 107 }
 108
 109 static void display(void)
 110 {
 111    GLfloat knots[8] = {0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0};
 112    GLfloat edgePt[5][2] = /* counter clockwise */
 113       {{0.0, 0.0}, {1.0, 0.0}, {1.0, 1.0}, {0.0, 1.0}, {0.0, 0.0}};
 114    GLfloat curvePt[4][2] = /* clockwise */
 115       {{0.25, 0.5}, {0.25, 0.75}, {0.75, 0.75}, {0.75, 0.5}};
 116    GLfloat curveKnots[8] =
 117       {0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0};
 118    GLfloat pwlPt[4][2] = /* clockwise */
 119       {{0.75, 0.5}, {0.5, 0.25}, {0.25, 0.5}};
 120
 121    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 122    glPushMatrix();
 123    glRotatef(330.0, 1.,0.,0.);
 124    glScalef (0.5, 0.5, 0.5);
 125
 126    gluBeginSurface(theNurb);
 127    gluNurbsSurface(theNurb, 8, knots, 8, knots,
 128                    4 * 3, 3, &ctlpoints[0][0][0],
 129                    4, 4, GL_MAP2_VERTEX_3);
 130    gluBeginTrim (theNurb);
 131       gluPwlCurve (theNurb, 5, &edgePt[0][0], 2, GLU_MAP1_TRIM_2);
 132    gluEndTrim (theNurb);
 133    gluBeginTrim (theNurb);
 134       gluNurbsCurve (theNurb, 8, curveKnots, 2,
 135                      &curvePt[0][0], 4, GLU_MAP1_TRIM_2);
 136       gluPwlCurve (theNurb, 3, &pwlPt[0][0], 2, GLU_MAP1_TRIM_2);
 137    gluEndTrim (theNurb);
 138    gluEndSurface(theNurb);
 139
 140    glPopMatrix();
 141    glFlush();
 142 }
 143
 144 static void reshape(int w, int h)
 145 {
 146    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
 147    glMatrixMode(GL_PROJECTION);
 148    glLoadIdentity();
 149    gluPerspective (45.0, (GLdouble)w/(GLdouble)h, 3.0, 8.0);
 150
 151    glMatrixMode(GL_MODELVIEW);
 152    glLoadIdentity();
 153    glTranslatef (0.0, 0.0, -5.0);
 154 }
 155
 156 /* ARGSUSED1 */
 157 static void keyboard(unsigned char key, int x, int y)
 158 {
 159    switch (key) {
 160       case 27:
 161          exit(0);
 162          break;
 163    }
 164 }
 165
 166 /*  Main Loop
 167  */
 168 int main(int argc, char** argv)
 169 {
 170    glutInit(&argc, argv);
 171    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 172    glutInitWindowSize (500, 500);
 173    glutInitWindowPosition (100, 100);
 174    glutCreateWindow(argv[0]);
 175    init();
 176    glutReshapeFunc(reshape);
 177    glutDisplayFunc(display);
 178    glutKeyboardFunc (keyboard);
 179    glutMainLoop();
 180    return 0;
 181 }