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31  * Unpublished-- rights reserved under the copyright laws of the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  *  movelight.c
40  *  This program demonstrates when to issue lighting and
41  *  transformation commands to render a model with a light
42  *  which is moved by a modeling transformation (rotate or
43  *  translate).  The light position is reset after the modeling
44  *  transformation is called.  The eye position does not change.
45  *
46  *  A sphere is drawn using a grey material characteristic.
47  *  A single light source illuminates the object.
48  *
49  *  Interaction:  pressing the left mouse button alters
50  *  the modeling transformation (x rotation) by 30 degrees.
51  *  The scene is then redrawn with the light in a new position.
52  */
53 #include "glut_wrap.h"
54 #include <stdlib.h>
55 
56 static int spin = 0;
57 
58 /*  Initialize material property, light source, lighting model,
59  *  and depth buffer.
60  */
init(void)61 static void init(void)
62 {
63    glClearColor (0.0, 0.0, 0.0, 0.0);
64    glShadeModel (GL_SMOOTH);
65    glEnable(GL_LIGHTING);
66    glEnable(GL_LIGHT0);
67    glEnable(GL_DEPTH_TEST);
68 }
69 
70 /*  Here is where the light position is reset after the modeling
71  *  transformation (glRotated) is called.  This places the
72  *  light at a new position in world coordinates.  The cube
73  *  represents the position of the light.
74  */
display(void)75 static void display(void)
76 {
77    GLfloat position[] = { 0.0, 0.0, 1.5, 1.0 };
78 
79    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
80    glPushMatrix ();
81    gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
82 
83    glPushMatrix ();
84    glRotated ((GLdouble) spin, 1.0, 0.0, 0.0);
85    glLightfv (GL_LIGHT0, GL_POSITION, position);
86 
87    glTranslated (0.0, 0.0, 1.5);
88    glDisable (GL_LIGHTING);
89    glColor3f (0.0, 1.0, 1.0);
90    glutWireCube (0.1);
91    glEnable (GL_LIGHTING);
92    glPopMatrix ();
93 
94    glutSolidTorus (0.275, 0.85, 8, 15);
95    glPopMatrix ();
96    glFlush ();
97 }
98 
reshape(int w,int h)99 static void reshape (int w, int h)
100 {
101    glViewport (0, 0, (GLsizei) w, (GLsizei) h);
102    glMatrixMode (GL_PROJECTION);
103    glLoadIdentity();
104    gluPerspective(40.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
105    glMatrixMode(GL_MODELVIEW);
106    glLoadIdentity();
107 }
108 
109 /* ARGSUSED2 */
mouse(int button,int state,int x,int y)110 static void mouse(int button, int state, int x, int y)
111 {
112    switch (button) {
113       case GLUT_LEFT_BUTTON:
114          if (state == GLUT_DOWN) {
115             spin = (spin + 30) % 360;
116             glutPostRedisplay();
117          }
118          break;
119       default:
120          break;
121    }
122 }
123 
124 /* ARGSUSED1 */
keyboard(unsigned char key,int x,int y)125 static void keyboard(unsigned char key, int x, int y)
126 {
127    switch (key) {
128       case 27:
129          exit(0);
130          break;
131    }
132 }
133 
main(int argc,char ** argv)134 int main(int argc, char** argv)
135 {
136    glutInit(&argc, argv);
137    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
138    glutInitWindowSize (500, 500);
139    glutInitWindowPosition (100, 100);
140    glutCreateWindow (argv[0]);
141    init ();
142    glutDisplayFunc(display);
143    glutReshapeFunc(reshape);
144    glutMouseFunc(mouse);
145    glutKeyboardFunc(keyboard);
146    glutMainLoop();
147    return 0;
148 }
149