3 * 3-D gear wheels. This program is in the public domain.
8 /* Conversion to GLUT by Mark J. Kilgard */
16 #define M_PI 3.14159265
20 static GLint Frames
= 0;
25 Draw a gear wheel. You'll probably want to call this function when
26 building a display list since we do a lot of trig here.
28 Input: inner_radius - radius of hole at center
29 outer_radius - radius at center of teeth
31 teeth - number of teeth
32 tooth_depth - depth of tooth
37 gear(GLfloat inner_radius
, GLfloat outer_radius
, GLfloat width
,
38 GLint teeth
, GLfloat tooth_depth
)
46 r1
= outer_radius
- tooth_depth
/ 2.0;
47 r2
= outer_radius
+ tooth_depth
/ 2.0;
49 da
= 2.0 * M_PI
/ teeth
/ 4.0;
51 glShadeModel(GL_FLAT
);
53 glNormal3f(0.0, 0.0, 1.0);
56 glBegin(GL_QUAD_STRIP
);
57 for (i
= 0; i
<= teeth
; i
++) {
58 angle
= i
* 2.0 * M_PI
/ teeth
;
59 glVertex3f(r0
* cos(angle
), r0
* sin(angle
), width
* 0.5);
60 glVertex3f(r1
* cos(angle
), r1
* sin(angle
), width
* 0.5);
62 glVertex3f(r0
* cos(angle
), r0
* sin(angle
), width
* 0.5);
63 glVertex3f(r1
* cos(angle
+ 3 * da
), r1
* sin(angle
+ 3 * da
), width
* 0.5);
68 /* draw front sides of teeth */
70 da
= 2.0 * M_PI
/ teeth
/ 4.0;
71 for (i
= 0; i
< teeth
; i
++) {
72 angle
= i
* 2.0 * M_PI
/ teeth
;
74 glVertex3f(r1
* cos(angle
), r1
* sin(angle
), width
* 0.5);
75 glVertex3f(r2
* cos(angle
+ da
), r2
* sin(angle
+ da
), width
* 0.5);
76 glVertex3f(r2
* cos(angle
+ 2 * da
), r2
* sin(angle
+ 2 * da
), width
* 0.5);
77 glVertex3f(r1
* cos(angle
+ 3 * da
), r1
* sin(angle
+ 3 * da
), width
* 0.5);
81 glNormal3f(0.0, 0.0, -1.0);
84 glBegin(GL_QUAD_STRIP
);
85 for (i
= 0; i
<= teeth
; i
++) {
86 angle
= i
* 2.0 * M_PI
/ teeth
;
87 glVertex3f(r1
* cos(angle
), r1
* sin(angle
), -width
* 0.5);
88 glVertex3f(r0
* cos(angle
), r0
* sin(angle
), -width
* 0.5);
90 glVertex3f(r1
* cos(angle
+ 3 * da
), r1
* sin(angle
+ 3 * da
), -width
* 0.5);
91 glVertex3f(r0
* cos(angle
), r0
* sin(angle
), -width
* 0.5);
96 /* draw back sides of teeth */
98 da
= 2.0 * M_PI
/ teeth
/ 4.0;
99 for (i
= 0; i
< teeth
; i
++) {
100 angle
= i
* 2.0 * M_PI
/ teeth
;
102 glVertex3f(r1
* cos(angle
+ 3 * da
), r1
* sin(angle
+ 3 * da
), -width
* 0.5);
103 glVertex3f(r2
* cos(angle
+ 2 * da
), r2
* sin(angle
+ 2 * da
), -width
* 0.5);
104 glVertex3f(r2
* cos(angle
+ da
), r2
* sin(angle
+ da
), -width
* 0.5);
105 glVertex3f(r1
* cos(angle
), r1
* sin(angle
), -width
* 0.5);
109 /* draw outward faces of teeth */
110 glBegin(GL_QUAD_STRIP
);
111 for (i
= 0; i
< teeth
; i
++) {
112 angle
= i
* 2.0 * M_PI
/ teeth
;
114 glVertex3f(r1
* cos(angle
), r1
* sin(angle
), width
* 0.5);
115 glVertex3f(r1
* cos(angle
), r1
* sin(angle
), -width
* 0.5);
116 u
= r2
* cos(angle
+ da
) - r1
* cos(angle
);
117 v
= r2
* sin(angle
+ da
) - r1
* sin(angle
);
118 len
= sqrt(u
* u
+ v
* v
);
121 glNormal3f(v
, -u
, 0.0);
122 glVertex3f(r2
* cos(angle
+ da
), r2
* sin(angle
+ da
), width
* 0.5);
123 glVertex3f(r2
* cos(angle
+ da
), r2
* sin(angle
+ da
), -width
* 0.5);
124 glNormal3f(cos(angle
), sin(angle
), 0.0);
125 glVertex3f(r2
* cos(angle
+ 2 * da
), r2
* sin(angle
+ 2 * da
), width
* 0.5);
126 glVertex3f(r2
* cos(angle
+ 2 * da
), r2
* sin(angle
+ 2 * da
), -width
* 0.5);
127 u
= r1
* cos(angle
+ 3 * da
) - r2
* cos(angle
+ 2 * da
);
128 v
= r1
* sin(angle
+ 3 * da
) - r2
* sin(angle
+ 2 * da
);
129 glNormal3f(v
, -u
, 0.0);
130 glVertex3f(r1
* cos(angle
+ 3 * da
), r1
* sin(angle
+ 3 * da
), width
* 0.5);
131 glVertex3f(r1
* cos(angle
+ 3 * da
), r1
* sin(angle
+ 3 * da
), -width
* 0.5);
132 glNormal3f(cos(angle
), sin(angle
), 0.0);
135 glVertex3f(r1
* cos(0), r1
* sin(0), width
* 0.5);
136 glVertex3f(r1
* cos(0), r1
* sin(0), -width
* 0.5);
140 glShadeModel(GL_SMOOTH
);
142 /* draw inside radius cylinder */
143 glBegin(GL_QUAD_STRIP
);
144 for (i
= 0; i
<= teeth
; i
++) {
145 angle
= i
* 2.0 * M_PI
/ teeth
;
146 glNormal3f(-cos(angle
), -sin(angle
), 0.0);
147 glVertex3f(r0
* cos(angle
), r0
* sin(angle
), -width
* 0.5);
148 glVertex3f(r0
* cos(angle
), r0
* sin(angle
), width
* 0.5);
154 static GLfloat view_rotx
= 20.0, view_roty
= 30.0, view_rotz
= 0.0;
155 static GLint gear1
, gear2
, gear3
;
156 static GLfloat angle
= 0.0;
161 glClear(GL_COLOR_BUFFER_BIT
| GL_DEPTH_BUFFER_BIT
);
164 glRotatef(view_rotx
, 1.0, 0.0, 0.0);
165 glRotatef(view_roty
, 0.0, 1.0, 0.0);
166 glRotatef(view_rotz
, 0.0, 0.0, 1.0);
169 glTranslatef(-3.0, -2.0, 0.0);
170 glRotatef(angle
, 0.0, 0.0, 1.0);
175 glTranslatef(3.1, -2.0, 0.0);
176 glRotatef(-2.0 * angle
- 9.0, 0.0, 0.0, 1.0);
181 glTranslatef(-3.1, 4.2, 0.0);
182 glRotatef(-2.0 * angle
- 25.0, 0.0, 0.0, 1.0);
192 GLint t
= glutGet(GLUT_ELAPSED_TIME
);
193 if (t
- T0
>= 5000) {
194 GLfloat seconds
= (t
- T0
) / 1000.0;
195 GLfloat fps
= Frames
/ seconds
;
196 printf("%d frames in %g seconds = %g FPS\n", Frames
, seconds
, fps
);
211 /* change view angle, exit upon ESC */
214 key(unsigned char k
, int x
, int y
)
223 case 27: /* Escape */
224 exit(0); /* FIXME: Shutdown and free resources cleanly in ggiglut */
232 /* change view angle */
235 special(int k
, int x
, int y
)
256 /* new window size or exposure */
258 reshape(int width
, int height
)
260 GLfloat h
= (GLfloat
) height
/ (GLfloat
) width
;
262 glViewport(0, 0, (GLint
) width
, (GLint
) height
);
263 glMatrixMode(GL_PROJECTION
);
265 glFrustum(-1.0, 1.0, -h
, h
, 5.0, 60.0);
266 glMatrixMode(GL_MODELVIEW
);
268 glTranslatef(0.0, 0.0, -40.0);
274 static GLfloat pos
[4] =
275 {5.0, 5.0, 10.0, 0.0};
276 static GLfloat red
[4] =
277 {0.8, 0.1, 0.0, 1.0};
278 static GLfloat green
[4] =
279 {0.0, 0.8, 0.2, 1.0};
280 static GLfloat blue
[4] =
281 {0.2, 0.2, 1.0, 1.0};
283 glLightfv(GL_LIGHT0
, GL_POSITION
, pos
);
284 glEnable(GL_CULL_FACE
);
285 glEnable(GL_LIGHTING
);
287 glEnable(GL_DEPTH_TEST
);
290 gear1
= glGenLists(1);
291 glNewList(gear1
, GL_COMPILE
);
292 glMaterialfv(GL_FRONT
, GL_AMBIENT_AND_DIFFUSE
, red
);
293 gear(1.0, 4.0, 1.0, 20, 0.7);
296 gear2
= glGenLists(1);
297 glNewList(gear2
, GL_COMPILE
);
298 glMaterialfv(GL_FRONT
, GL_AMBIENT_AND_DIFFUSE
, green
);
299 gear(0.5, 2.0, 2.0, 10, 0.7);
302 gear3
= glGenLists(1);
303 glNewList(gear3
, GL_COMPILE
);
304 glMaterialfv(GL_FRONT
, GL_AMBIENT_AND_DIFFUSE
, blue
);
305 gear(1.3, 2.0, 0.5, 10, 0.7);
308 glEnable(GL_NORMALIZE
);
314 if (vis
== GLUT_VISIBLE
)
320 int main(int argc
, char *argv
[])
322 glutInit(&argc
, argv
);
323 glutInitDisplayMode(GLUT_RGB
| GLUT_DEPTH
| GLUT_DOUBLE
);
325 // glutInitWindowPosition(0, 0);
326 // glutInitWindowSize(300, 300);
327 glutCreateWindow("Gears");
330 glutDisplayFunc(draw
);
331 glutReshapeFunc(reshape
);
332 glutKeyboardFunc(key
);
333 glutSpecialFunc(special
);
334 glutVisibilityFunc(visible
);