progs/egl/opengl/eglgears.c

   1 /*
   2  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included
  12  * in all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  15  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  18  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  19  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20  */
  21
  22 /*
  23  * This is a port of the infamous "glxgears" demo to straight EGL
  24  * Port by Dane Rushton 10 July 2005
  25  *
  26  * No command line options.
  27  * Program runs for 5 seconds then exits, outputing framerate to console
  28  */
  29
  30 #include <math.h>
  31 #include <GL/gl.h>
  32 #include <EGL/egl.h>
  33
  34 #include "eglut.h"
  35
  36 static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
  37 static GLint gear1, gear2, gear3;
  38 static GLfloat angle = 0.0;
  39
  40 /*
  41  *
  42  *  Draw a gear wheel.  You'll probably want to call this function when
  43  *  building a display list since we do a lot of trig here.
  44  *
  45  *  Input:  inner_radius - radius of hole at center
  46  *          outer_radius - radius at center of teeth
  47  *          width - width of gear
  48  *          teeth - number of teeth
  49  *          tooth_depth - depth of tooth
  50  */
  51 static void
  52 gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
  53      GLint teeth, GLfloat tooth_depth)
  54 {
  55    GLint i;
  56    GLfloat r0, r1, r2;
  57    GLfloat angle, da;
  58    GLfloat u, v, len;
  59
  60    r0 = inner_radius;
  61    r1 = outer_radius - tooth_depth / 2.0;
  62    r2 = outer_radius + tooth_depth / 2.0;
  63
  64    da = 2.0 * M_PI / teeth / 4.0;
  65
  66    glShadeModel(GL_FLAT);
  67
  68    glNormal3f(0.0, 0.0, 1.0);
  69
  70    /* draw front face */
  71    glBegin(GL_QUAD_STRIP);
  72    for (i = 0; i <= teeth; i++) {
  73       angle = i * 2.0 * M_PI / teeth;
  74       glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
  75       glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
  76       if (i < teeth) {
  77          glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
  78          glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
  79                     width * 0.5);
  80       }
  81    }
  82    glEnd();
  83
  84    /* draw front sides of teeth */
  85    glBegin(GL_QUADS);
  86    da = 2.0 * M_PI / teeth / 4.0;
  87    for (i = 0; i < teeth; i++) {
  88       angle = i * 2.0 * M_PI / teeth;
  89
  90       glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
  91       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
  92       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
  93                  width * 0.5);
  94       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
  95                  width * 0.5);
  96    }
  97    glEnd();
  98
  99    glNormal3f(0.0, 0.0, -1.0);
 100
 101    /* draw back face */
 102    glBegin(GL_QUAD_STRIP);
 103    for (i = 0; i <= teeth; i++) {
 104       angle = i * 2.0 * M_PI / teeth;
 105       glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
 106       glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
 107       if (i < teeth) {
 108          glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 109                     -width * 0.5);
 110          glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
 111       }
 112    }
 113    glEnd();
 114
 115    /* draw back sides of teeth */
 116    glBegin(GL_QUADS);
 117    da = 2.0 * M_PI / teeth / 4.0;
 118    for (i = 0; i < teeth; i++) {
 119       angle = i * 2.0 * M_PI / teeth;
 120
 121       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 122                  -width * 0.5);
 123       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 124                  -width * 0.5);
 125       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
 126       glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
 127    }
 128    glEnd();
 129
 130    /* draw outward faces of teeth */
 131    glBegin(GL_QUAD_STRIP);
 132    for (i = 0; i < teeth; i++) {
 133       angle = i * 2.0 * M_PI / teeth;
 134
 135       glVertex3f(r1 * cos(angle), r1 * sin(angle), width * 0.5);
 136       glVertex3f(r1 * cos(angle), r1 * sin(angle), -width * 0.5);
 137       u = r2 * cos(angle + da) - r1 * cos(angle);
 138       v = r2 * sin(angle + da) - r1 * sin(angle);
 139       len = sqrt(u * u + v * v);
 140       u /= len;
 141       v /= len;
 142       glNormal3f(v, -u, 0.0);
 143       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), width * 0.5);
 144       glVertex3f(r2 * cos(angle + da), r2 * sin(angle + da), -width * 0.5);
 145       glNormal3f(cos(angle), sin(angle), 0.0);
 146       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 147                  width * 0.5);
 148       glVertex3f(r2 * cos(angle + 2 * da), r2 * sin(angle + 2 * da),
 149                  -width * 0.5);
 150       u = r1 * cos(angle + 3 * da) - r2 * cos(angle + 2 * da);
 151       v = r1 * sin(angle + 3 * da) - r2 * sin(angle + 2 * da);
 152       glNormal3f(v, -u, 0.0);
 153       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 154                  width * 0.5);
 155       glVertex3f(r1 * cos(angle + 3 * da), r1 * sin(angle + 3 * da),
 156                  -width * 0.5);
 157       glNormal3f(cos(angle), sin(angle), 0.0);
 158    }
 159
 160    glVertex3f(r1 * cos(0), r1 * sin(0), width * 0.5);
 161    glVertex3f(r1 * cos(0), r1 * sin(0), -width * 0.5);
 162
 163    glEnd();
 164
 165    glShadeModel(GL_SMOOTH);
 166
 167    /* draw inside radius cylinder */
 168    glBegin(GL_QUAD_STRIP);
 169    for (i = 0; i <= teeth; i++) {
 170       angle = i * 2.0 * M_PI / teeth;
 171       glNormal3f(-cos(angle), -sin(angle), 0.0);
 172       glVertex3f(r0 * cos(angle), r0 * sin(angle), -width * 0.5);
 173       glVertex3f(r0 * cos(angle), r0 * sin(angle), width * 0.5);
 174    }
 175    glEnd();
 176 }
 177
 178
 179 static void
 180 draw(void)
 181 {
 182    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 183
 184    glPushMatrix();
 185    glRotatef(view_rotx, 1.0, 0.0, 0.0);
 186    glRotatef(view_roty, 0.0, 1.0, 0.0);
 187    glRotatef(view_rotz, 0.0, 0.0, 1.0);
 188
 189    glPushMatrix();
 190    glTranslatef(-3.0, -2.0, 0.0);
 191    glRotatef(angle, 0.0, 0.0, 1.0);
 192    glCallList(gear1);
 193    glPopMatrix();
 194
 195    glPushMatrix();
 196    glTranslatef(3.1, -2.0, 0.0);
 197    glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
 198    glCallList(gear2);
 199    glPopMatrix();
 200
 201    glPushMatrix();
 202    glTranslatef(-3.1, 4.2, 0.0);
 203    glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
 204    glCallList(gear3);
 205    glPopMatrix();
 206
 207    glPopMatrix();
 208 }
 209
 210
 211 static void
 212 idle(void)
 213 {
 214   static double t0 = -1.;
 215   double dt, t = eglutGet(EGLUT_ELAPSED_TIME) / 1000.0;
 216   if (t0 < 0.0)
 217     t0 = t;
 218   dt = t - t0;
 219   t0 = t;
 220
 221   angle += 70.0 * dt;  /* 70 degrees per second */
 222   angle = fmod(angle, 360.0); /* prevents eventual overflow */
 223
 224   eglutPostRedisplay();
 225 }
 226
 227 /* new window size or exposure */
 228 static void
 229 reshape(int width, int height)
 230 {
 231    GLfloat h = (GLfloat) height / (GLfloat) width;
 232
 233    glViewport(0, 0, (GLint) width, (GLint) height);
 234
 235    glMatrixMode(GL_PROJECTION);
 236    glLoadIdentity();
 237    glFrustum(-1.0, 1.0, -h, h, 5.0, 60.0);
 238
 239    glMatrixMode(GL_MODELVIEW);
 240    glLoadIdentity();
 241    glTranslatef(0.0, 0.0, -40.0);
 242 }
 243
 244
 245
 246 static void
 247 init(void)
 248 {
 249    static GLfloat pos[4] = { 5.0, 5.0, 10.0, 0.0 };
 250    static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
 251    static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
 252    static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };
 253
 254    glLightfv(GL_LIGHT0, GL_POSITION, pos);
 255    glEnable(GL_CULL_FACE);
 256    glEnable(GL_LIGHTING);
 257    glEnable(GL_LIGHT0);
 258    glEnable(GL_DEPTH_TEST);
 259
 260    /* make the gears */
 261    gear1 = glGenLists(1);
 262    glNewList(gear1, GL_COMPILE);
 263    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red);
 264    gear(1.0, 4.0, 1.0, 20, 0.7);
 265    glEndList();
 266
 267    gear2 = glGenLists(1);
 268    glNewList(gear2, GL_COMPILE);
 269    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green);
 270    gear(0.5, 2.0, 2.0, 10, 0.7);
 271    glEndList();
 272
 273    gear3 = glGenLists(1);
 274    glNewList(gear3, GL_COMPILE);
 275    glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue);
 276    gear(1.3, 2.0, 0.5, 10, 0.7);
 277    glEndList();
 278
 279    glEnable(GL_NORMALIZE);
 280 }
 281
 282 int
 283 main(int argc, char *argv[])
 284 {
 285    eglutInitWindowSize(300, 300);
 286    eglutInitAPIMask(EGLUT_OPENGL_BIT);
 287    eglutInit(argc, argv);
 288
 289    eglutCreateWindow("eglgears");
 290
 291    eglutIdleFunc(idle);
 292    eglutReshapeFunc(reshape);
 293    eglutDisplayFunc(draw);
 294
 295    init();
 296    glDrawBuffer(GL_BACK);
 297
 298    eglutMainLoop();
 299
 300    return 0;
 301 }