progs/ggi/gears.c

   1 /* $Id: gears.c,v 1.3 1999/08/22 08:56:50 jtaylor Exp $ */
   2
   3 /*
   4  * 3-D gear wheels.  This program is in the public domain.
   5  *
   6  * Brian Paul
   7  */
   8
   9 /* Conversion to GLUT by Mark J. Kilgard */
  10
  11 #include <math.h>
  12 #include <stdlib.h>
  13 #include <stdio.h>
  14 #include <GL/glut.h>
  15
  16 #ifndef M_PI
  17 #define M_PI 3.14159265
  18 #endif
  19
  20 static GLint T0 = 0;
  21 static GLint Frames = 0;
  22
  23
  24 /**
  25
  26   Draw a gear wheel.  You'll probably want to call this function when
  27   building a display list since we do a lot of trig here.
  28
  29   Input:  inner_radius - radius of hole at center
  30           outer_radius - radius at center of teeth
  31           width - width of gear
  32           teeth - number of teeth
  33           tooth_depth - depth of tooth
  34
  35  **/
  36
  37 static void
  38 gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
  39   GLint teeth, GLfloat tooth_depth)
  40 {
  41   GLint i;
  42   GLfloat r0, r1, r2;
  43   GLfloat angle, da;
  44   GLfloat u, v, len;
  45
  46   r0 = inner_radius;
  47   r1 = outer_radius - tooth_depth / 2.0;
  48   r2 = outer_radius + tooth_depth / 2.0;
  49
  50   da = 2.0 * M_PI / teeth / 4.0;
  51
  52   glShadeModel(GL_FLAT);
  53
  54   glNormal3f(0.0, 0.0, 1.0);
  55
  56   /* draw front face */
  57   glBegin(GL_QUAD_STRIP);
  58   for (i = 0; i <= teeth; i++) {
  59     angle = i * 2.0 * M_PI / teeth;
  60     glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
  61     glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
  62     if (i < teeth) {
  63       glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
  64       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
  65     }
  66   }
  67   glEnd();
  68
  69   /* draw front sides of teeth */
  70   glBegin(GL_QUADS);
  71   da = 2.0 * M_PI / teeth / 4.0;
  72   for (i = 0; i < teeth; i++) {
  73     angle = i * 2.0 * M_PI / teeth;
  74
  75     glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
  76     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
  77     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
  78     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
  79   }
  80   glEnd();
  81
  82   glNormal3f(0.0, 0.0, -1.0);
  83
  84   /* draw back face */
  85   glBegin(GL_QUAD_STRIP);
  86   for (i = 0; i <= teeth; i++) {
  87     angle = i * 2.0 * M_PI / teeth;
  88     glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
  89     glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
  90     if (i < teeth) {
  91       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
  92       glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
  93     }
  94   }
  95   glEnd();
  96
  97   /* draw back sides of teeth */
  98   glBegin(GL_QUADS);
  99   da = 2.0 * M_PI / teeth / 4.0;
 100   for (i = 0; i < teeth; i++) {
 101     angle = i * 2.0 * M_PI / teeth;
 102
 103     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
 104     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
 105     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
 106     glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
 107   }
 108   glEnd();
 109
 110   /* draw outward faces of teeth */
 111   glBegin(GL_QUAD_STRIP);
 112   for (i = 0; i < teeth; i++) {
 113     angle = i * 2.0 * M_PI / teeth;
 114
 115     glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
 116     glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
 117     u = r2 * cos(angle + da) - r1 * cos(angle);
 118     v = r2 * sin(angle + da) - r1 * sin(angle);
 119     len = sqrt(u * u + v * v);
 120     u /= len;
 121     v /= len;
 122     glNormal3f(v, -u, 0.0);
 123     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
 124     glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
 125     glNormal3f(cos(angle), sin(angle), 0.0);
 126     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), width * 0.5);
 127     glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da), -width * 0.5);
 128     u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
 129     v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
 130     glNormal3f(v, -u, 0.0);
 131     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), width * 0.5);
 132     glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da), -width * 0.5);
 133     glNormal3f(cos(angle), sin(angle), 0.0);
 134   }
 135
 136   glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
 137   glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
 138
 139   glEnd();
 140
 141   glShadeModel(GL_SMOOTH);
 142
 143   /* draw inside radius cylinder */
 144   glBegin(GL_QUAD_STRIP);
 145   for (i = 0; i <= teeth; i++) {
 146     angle = i * 2.0 * M_PI / teeth;
 147     glNormal3f(-cos(angle), -sin(angle), 0.0);
 148     glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
 149     glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
 150   }
 151   glEnd();
 152
 153 }
 154
 155 static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
 156 static GLint gear1, gear2, gear3;
 157 static GLfloat angle = 0.0;
 158
 159 static void
 160 draw(void)
 161 {
 162   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 163
 164   glPushMatrix();
 165   glRotatef(view_rotx, 1.0, 0.0, 0.0);
 166   glRotatef(view_roty, 0.0, 1.0, 0.0);
 167   glRotatef(view_rotz, 0.0, 0.0, 1.0);
 168
 169   glPushMatrix();
 170   glTranslatef(-3.0, -2.0, 0.0);
 171   glRotatef(angle, 0.0, 0.0, 1.0);
 172   glCallList(gear1);
 173   glPopMatrix();
 174
 175   glPushMatrix();
 176   glTranslatef(3.1, -2.0, 0.0);
 177   glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
 178   glCallList(gear2);
 179   glPopMatrix();
 180
 181   glPushMatrix();
 182   glTranslatef(-3.1, 4.2, 0.0);
 183   glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
 184   glCallList(gear3);
 185   glPopMatrix();
 186
 187   glPopMatrix();
 188
 189   glutSwapBuffers();
 190
 191   Frames++;
 192   {
 193      GLint t = glutGet(GLUT_ELAPSED_TIME);
 194      if (t - T0 >= 5000) {
 195         GLfloat seconds = (t - T0) / 1000.0;
 196         GLfloat fps = Frames / seconds;
 197         printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps);
 198         T0 = t;
 199         Frames = 0;
 200      }
 201   }
 202 }
 203
 204
 205 static void
 206 idle(void)
 207 {
 208   angle += 2.0;
 209   glutPostRedisplay();
 210 }
 211
 212 /* change view angle, exit upon ESC */
 213 /* ARGSUSED1 */
 214 static void
 215 key(unsigned char k, int x, int y)
 216 {
 217   switch (k) {
 218   case 'z':
 219     view_rotz += 5.0;
 220     break;
 221   case 'Z':
 222     view_rotz -= 5.0;
 223     break;
 224   case 27:  /* Escape */
 225     exit(0); /* FIXME: Shutdown and free resources cleanly in ggiglut */
 226     break;
 227   default:
 228     return;
 229   }
 230   glutPostRedisplay();
 231 }
 232
 233 /* change view angle */
 234 /* ARGSUSED1 */
 235 static void
 236 special(int k, int x, int y)
 237 {
 238   switch (k) {
 239   case GLUT_KEY_UP:
 240     view_rotx += 5.0;
 241     break;
 242   case GLUT_KEY_DOWN:
 243     view_rotx -= 5.0;
 244     break;
 245   case GLUT_KEY_LEFT:
 246     view_roty += 5.0;
 247     break;
 248   case GLUT_KEY_RIGHT:
 249     view_roty -= 5.0;
 250     break;
 251   default:
 252     return;
 253   }
 254   glutPostRedisplay();
 255 }
 256
 257 /* new window size or exposure */
 258 static void
 259 reshape(int width, int height)
 260 {
 261   GLfloat h = (GLfloat) height / (GLfloat) width;
 262
 263   glViewport(0, 0, (GLint) width, (GLint) height);
 264   glMatrixMode(GL_PROJECTION);
 265   glLoadIdentity();
 266   glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
 267   glMatrixMode(GL_MODELVIEW);
 268   glLoadIdentity();
 269   glTranslatef(0.0, 0.0, -40.0);
 270 }
 271
 272 static void
 273 init(void)
 274 {
 275   static GLfloat pos[4] =
 276   {5.0, 5.0, 10.0, 0.0};
 277   static GLfloat red[4] =
 278   {0.8, 0.1, 0.0, 1.0};
 279   static GLfloat green[4] =
 280   {0.0, 0.8, 0.2, 1.0};
 281   static GLfloat blue[4] =
 282   {0.2, 0.2, 1.0, 1.0};
 283
 284   glLightfv(GL_LIGHT0, GL_POSITION, pos);
 285   glEnable(GL_CULL_FACE);
 286   glEnable(GL_LIGHTING);
 287   glEnable(GL_LIGHT0);
 288   glEnable(GL_DEPTH_TEST);
 289
 290   /* make the gears */
 291   gear1 = glGenLists(1);
 292   glNewList(gear1, GL_COMPILE);
 293   glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
 294   gear(1.0, 4.0, 1.0, 20, 0.7);
 295   glEndList();
 296
 297   gear2 = glGenLists(1);
 298   glNewList(gear2, GL_COMPILE);
 299   glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
 300   gear(0.5, 2.0, 2.0, 10, 0.7);
 301   glEndList();
 302
 303   gear3 = glGenLists(1);
 304   glNewList(gear3, GL_COMPILE);
 305   glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
 306   gear(1.3, 2.0, 0.5, 10, 0.7);
 307   glEndList();
 308
 309   glEnable(GL_NORMALIZE);
 310 }
 311
 312 void
 313 visible(int vis)
 314 {
 315   if (vis == GLUT_VISIBLE)
 316     glutIdleFunc(idle);
 317   else
 318     glutIdleFunc(NULL);
 319 }
 320
 321 int main(int argc, char *argv[])
 322 {
 323         glutInit(&argc, argv);
 324         glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
 325
 326 //      glutInitWindowPosition(0, 0);
 327 //      glutInitWindowSize(300, 300);
 328         glutCreateWindow("Gears");
 329         init();
 330
 331         glutDisplayFunc(draw);
 332         glutReshapeFunc(reshape);
 333         glutKeyboardFunc(key);
 334         glutSpecialFunc(special);
 335         glutVisibilityFunc(visible);
 336
 337         glutMainLoop();
 338
 339         return 0;
 340 }