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/*
* Copyright (c) 1993-1997, 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* Unpublished-- rights reserved under the copyright laws of the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.
*/
/*
* trim.c
* This program draws a NURBS surface in the shape of a
* symmetrical hill, using both a NURBS curve and pwl
* (piecewise linear) curve to trim part of the surface.
*/
#include <stdlib.h>
#include <GL/glut.h>
#include <stdio.h>
#ifndef CALLBACK
#define CALLBACK
#endif
GLfloat ctlpoints[4][4][3];
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] = 3.0;
else
ctlpoints[u][v][2] = -3.0;
}
}
}
void nurbsError(GLenum errorCode)
{
const GLubyte *estring;
estring = gluErrorString(errorCode);
fprintf (stderr, "Nurbs Error: %s\n", (char *) estring);
exit (0);
}
/* Initialize material property and depth buffer.
*/
void init(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, 0.0);
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);
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);
gluNurbsCallback(theNurb, GLU_ERROR,
(GLvoid (CALLBACK*) ()) nurbsError);
}
void display(void)
{
GLfloat knots[8] = {0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0};
GLfloat edgePt[5][2] = /* counter clockwise */
{{0.0, 0.0}, {1.0, 0.0}, {1.0, 1.0}, {0.0, 1.0}, {0.0, 0.0}};
GLfloat curvePt[4][2] = /* clockwise */
{{0.25, 0.5}, {0.25, 0.75}, {0.75, 0.75}, {0.75, 0.5}};
GLfloat curveKnots[8] =
{0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0};
GLfloat pwlPt[4][2] = /* clockwise */
{{0.75, 0.5}, {0.5, 0.25}, {0.25, 0.5}};
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(330.0, 1.,0.,0.);
glScalef (0.5, 0.5, 0.5);
gluBeginSurface(theNurb);
gluNurbsSurface(theNurb, 8, knots, 8, knots,
4 * 3, 3, &ctlpoints[0][0][0],
4, 4, GL_MAP2_VERTEX_3);
gluBeginTrim (theNurb);
gluPwlCurve (theNurb, 5, &edgePt[0][0], 2, GLU_MAP1_TRIM_2);
gluEndTrim (theNurb);
gluBeginTrim (theNurb);
gluNurbsCurve (theNurb, 8, curveKnots, 2,
&curvePt[0][0], 4, GLU_MAP1_TRIM_2);
gluPwlCurve (theNurb, 3, &pwlPt[0][0], 2, GLU_MAP1_TRIM_2);
gluEndTrim (theNurb);
gluEndSurface(theNurb);
glPopMatrix();
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective (45.0, (GLdouble)w/(GLdouble)h, 3.0, 8.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef (0.0, 0.0, -5.0);
}
/* ARGSUSED1 */
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(0);
break;
}
}
/* Main Loop
*/
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();
glutReshapeFunc(reshape);
glutDisplayFunc(display);
glutKeyboardFunc (keyboard);
glutMainLoop();
return 0;
}
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