progs/xdemos/vgears.c

   1
   2 /*
   3  * Spinning gears demo for Linux SVGA/Mesa interface in 32K color mode.
   4  *
   5  * Compile with:  gcc vgears.c -I../include -L../lib -lMesaGL -lX11 -lXext
   6  *   -lvga -lm -o vgears
   7  *
   8  * This program is in the public domain.
   9  * Brian Paul, January 1996
  10  */
  11
  12
  13 #include <vga.h>
  14 #include <math.h>
  15 #include "GL/svgamesa.h"
  16 #include "GL/gl.h"
  17
  18
  19 int width = 800, height = 600;
  20
  21 SVGAMesaContext vmc;
  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 static void gear( GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
  36                   GLint teeth, GLfloat tooth_depth )
  37 {
  38    GLint i;
  39    GLfloat r0, r1, r2;
  40    GLfloat angle, da;
  41    GLfloat u, v, len;
  42
  43    r0 = inner_radius;
  44    r1 = outer_radius - tooth_depth/2.0;
  45    r2 = outer_radius + tooth_depth/2.0;
  46
  47    da = 2.0*M_PI / teeth / 4.0;
  48
  49    glShadeModel( GL_FLAT );
  50
  51    glNormal3f( 0.0, 0.0, 1.0 );
  52
  53    /* draw front face */
  54    glBegin( GL_QUAD_STRIP );
  55    for (i=0;i<=teeth;i++) {
  56       angle = i * 2.0*M_PI / teeth;
  57       glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
  58       glVertex3f( r1*cos(angle), r1*sin(angle), width*0.5 );
  59       glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
  60       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
  61    }
  62    glEnd();
  63
  64    /* draw front sides of teeth */
  65    glBegin( GL_QUADS );
  66    da = 2.0*M_PI / teeth / 4.0;
  67    for (i=0;i<teeth;i++) {
  68       angle = i * 2.0*M_PI / teeth;
  69
  70       glVertex3f( r1*cos(angle),      r1*sin(angle),      width*0.5 );
  71       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),   width*0.5 );
  72       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), width*0.5 );
  73       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
  74    }
  75    glEnd();
  76
  77
  78    glNormal3f( 0.0, 0.0, -1.0 );
  79
  80    /* draw back face */
  81    glBegin( GL_QUAD_STRIP );
  82    for (i=0;i<=teeth;i++) {
  83       angle = i * 2.0*M_PI / teeth;
  84       glVertex3f( r1*cos(angle), r1*sin(angle), -width*0.5 );
  85       glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
  86       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
  87       glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
  88    }
  89    glEnd();
  90
  91    /* draw back sides of teeth */
  92    glBegin( GL_QUADS );
  93    da = 2.0*M_PI / teeth / 4.0;
  94    for (i=0;i<teeth;i++) {
  95       angle = i * 2.0*M_PI / teeth;
  96
  97       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
  98       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), -width*0.5 );
  99       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),   -width*0.5 );
 100       glVertex3f( r1*cos(angle),      r1*sin(angle),      -width*0.5 );
 101    }
 102    glEnd();
 103
 104
 105    /* draw outward faces of teeth */
 106    glBegin( GL_QUAD_STRIP );
 107    for (i=0;i<teeth;i++) {
 108       angle = i * 2.0*M_PI / teeth;
 109
 110       glVertex3f( r1*cos(angle),      r1*sin(angle),       width*0.5 );
 111       glVertex3f( r1*cos(angle),      r1*sin(angle),      -width*0.5 );
 112       u = r2*cos(angle+da) - r1*cos(angle);
 113       v = r2*sin(angle+da) - r1*sin(angle);
 114       len = sqrt( u*u + v*v );
 115       u /= len;
 116       v /= len;
 117       glNormal3f( v, -u, 0.0 );
 118       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),    width*0.5 );
 119       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),   -width*0.5 );
 120       glNormal3f( cos(angle), sin(angle), 0.0 );
 121       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da),  width*0.5 );
 122       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), -width*0.5 );
 123       u = r1*cos(angle+3*da) - r2*cos(angle+2*da);
 124       v = r1*sin(angle+3*da) - r2*sin(angle+2*da);
 125       glNormal3f( v, -u, 0.0 );
 126       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da),  width*0.5 );
 127       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
 128       glNormal3f( cos(angle), sin(angle), 0.0 );
 129    }
 130
 131    glVertex3f( r1*cos(0), r1*sin(0), width*0.5 );
 132    glVertex3f( r1*cos(0), r1*sin(0), -width*0.5 );
 133
 134    glEnd();
 135
 136
 137    glShadeModel( GL_SMOOTH );
 138
 139    /* draw inside radius cylinder */
 140    glBegin( GL_QUAD_STRIP );
 141    for (i=0;i<=teeth;i++) {
 142       angle = i * 2.0*M_PI / teeth;
 143       glNormal3f( -cos(angle), -sin(angle), 0.0 );
 144       glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
 145       glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
 146    }
 147    glEnd();
 148
 149 }
 150
 151
 152 static GLfloat view_rotx=20.0, view_roty=30.0, view_rotz=0.0;
 153 static GLint gear1, gear2, gear3;
 154 static GLfloat angle = 0.0;
 155
 156 static GLuint limit;
 157 static GLuint count = 1;
 158
 159
 160 static void draw( void )
 161 {
 162    angle += 2.0;
 163
 164    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 165
 166    glPushMatrix();
 167    glRotatef( view_rotx, 1.0, 0.0, 0.0 );
 168    glRotatef( view_roty, 0.0, 1.0, 0.0 );
 169    glRotatef( view_rotz, 0.0, 0.0, 1.0 );
 170
 171    glPushMatrix();
 172    glTranslatef( -3.0, -2.0, 0.0 );
 173    glRotatef( angle, 0.0, 0.0, 1.0 );
 174    glCallList(gear1);
 175    glPopMatrix();
 176
 177    glPushMatrix();
 178    glTranslatef( 3.1, -2.0, 0.0 );
 179    glRotatef( -2.0*angle-9.0, 0.0, 0.0, 1.0 );
 180    glCallList(gear2);
 181    glPopMatrix();
 182
 183    glPushMatrix();
 184    glTranslatef( -3.1, 4.2, 0.0 );
 185    glRotatef( -2.0*angle-25.0, 0.0, 0.0, 1.0 );
 186    glCallList(gear3);
 187    glPopMatrix();
 188
 189    glPopMatrix();
 190
 191    SVGAMesaSwapBuffers();
 192 }
 193
 194
 195 static void init( void )
 196 {
 197    static GLfloat pos[4] = {5.0, 5.0, 10.0, 1.0 };
 198    static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0 };
 199    static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0 };
 200    static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0 };
 201
 202    GLfloat w = (float) width / (float) height;
 203    GLfloat h = 1.0;
 204
 205    glLightfv( GL_LIGHT0, GL_POSITION, pos );
 206    glEnable( GL_CULL_FACE );
 207    glEnable( GL_LIGHTING );
 208    glEnable( GL_LIGHT0 );
 209    glEnable( GL_DEPTH_TEST );
 210
 211    /* make the gears */
 212    gear1 = glGenLists(1);
 213    glNewList(gear1, GL_COMPILE);
 214    glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red );
 215    gear( 1.0, 4.0, 1.0, 20, 0.7 );
 216    glEndList();
 217
 218    gear2 = glGenLists(1);
 219    glNewList(gear2, GL_COMPILE);
 220    glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green );
 221    gear( 0.5, 2.0, 2.0, 10, 0.7 );
 222    glEndList();
 223
 224    gear3 = glGenLists(1);
 225    glNewList(gear3, GL_COMPILE);
 226    glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue );
 227    gear( 1.3, 2.0, 0.5, 10, 0.7 );
 228    glEndList();
 229
 230    glEnable( GL_NORMALIZE );
 231
 232
 233    glViewport( 0, 0, width, height );
 234    glMatrixMode(GL_PROJECTION);
 235    glLoadIdentity();
 236    if (width>height) {
 237       GLfloat w = (GLfloat) width / (GLfloat) height;
 238       glFrustum( -w, w, -1.0, 1.0, 5.0, 60.0 );
 239    }
 240    else {
 241       GLfloat h = (GLfloat) height / (GLfloat) width;
 242       glFrustum( -1.0, 1.0, -h, h, 5.0, 60.0 );
 243    }
 244
 245    glMatrixMode(GL_MODELVIEW);
 246    glLoadIdentity();
 247    glTranslatef( 0.0, 0.0, -40.0 );
 248 }
 249
 250 void setup( void )
 251 {
 252    vga_init();
 253
 254    vga_setmode(G800x600x32K);
 255 /*   gl_setcontextvga(G800x600x32K);*/
 256
 257    vmc = SVGAMesaCreateContext(GL_TRUE);
 258    SVGAMesaMakeCurrent( vmc );
 259 }
 260
 261
 262 void end( void )
 263 {
 264    SVGAMesaDestroyContext( vmc );
 265
 266    vga_setmode( TEXT );
 267 }
 268
 269
 270 int main( int argc, char *argv[] )
 271 {
 272    int i;
 273
 274    setup();
 275    init();
 276    for (i=0;i<4;i++) {
 277       draw(); /*SVGAMesaSwapBuffers();*/
 278    }
 279    end();
 280    return 0;
 281 }