progs/xdemos/vgears.c

   1 /* $ID$ */
   2
   3 /*
   4  * Spinning gears demo for Linux SVGA/Mesa interface in 32K color mode.
   5  *
   6  * Compile with:  gcc vgears.c -I../include -L../lib -lMesaGL -lX11 -lXext
   7  *   -lvga -lm -o vgears
   8  *
   9  * This program is in the public domain.
  10  * Brian Paul, January 1996
  11  */
  12
  13
  14 #include <vga.h>
  15 #include <math.h>
  16 #include "GL/svgamesa.h"
  17 #include "GL/gl.h"
  18
  19
  20 int width = 800, height = 600;
  21
  22 SVGAMesaContext vmc;
  23
  24
  25
  26 /*
  27  * Draw a gear wheel.  You'll probably want to call this function when
  28  * building a display list since we do a lot of trig here.
  29  *
  30  * Input:  inner_radius - radius of hole at center
  31  *         outer_radius - radius at center of teeth
  32  *         width - width of gear
  33  *         teeth - number of teeth
  34  *         tooth_depth - depth of tooth
  35  */
  36 static void gear( GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
  37                   GLint teeth, GLfloat tooth_depth )
  38 {
  39    GLint i;
  40    GLfloat r0, r1, r2;
  41    GLfloat angle, da;
  42    GLfloat u, v, len;
  43
  44    r0 = inner_radius;
  45    r1 = outer_radius - tooth_depth/2.0;
  46    r2 = outer_radius + tooth_depth/2.0;
  47
  48    da = 2.0*M_PI / teeth / 4.0;
  49
  50    glShadeModel( GL_FLAT );
  51
  52    glNormal3f( 0.0, 0.0, 1.0 );
  53
  54    /* draw front face */
  55    glBegin( GL_QUAD_STRIP );
  56    for (i=0;i<=teeth;i++) {
  57       angle = i * 2.0*M_PI / teeth;
  58       glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
  59       glVertex3f( r1*cos(angle), r1*sin(angle), width*0.5 );
  60       glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
  61       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
  62    }
  63    glEnd();
  64
  65    /* draw front sides of teeth */
  66    glBegin( GL_QUADS );
  67    da = 2.0*M_PI / teeth / 4.0;
  68    for (i=0;i<teeth;i++) {
  69       angle = i * 2.0*M_PI / teeth;
  70
  71       glVertex3f( r1*cos(angle),      r1*sin(angle),      width*0.5 );
  72       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),   width*0.5 );
  73       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), width*0.5 );
  74       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), width*0.5 );
  75    }
  76    glEnd();
  77
  78
  79    glNormal3f( 0.0, 0.0, -1.0 );
  80
  81    /* draw back face */
  82    glBegin( GL_QUAD_STRIP );
  83    for (i=0;i<=teeth;i++) {
  84       angle = i * 2.0*M_PI / teeth;
  85       glVertex3f( r1*cos(angle), r1*sin(angle), -width*0.5 );
  86       glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
  87       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
  88       glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
  89    }
  90    glEnd();
  91
  92    /* draw back sides of teeth */
  93    glBegin( GL_QUADS );
  94    da = 2.0*M_PI / teeth / 4.0;
  95    for (i=0;i<teeth;i++) {
  96       angle = i * 2.0*M_PI / teeth;
  97
  98       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
  99       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), -width*0.5 );
 100       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),   -width*0.5 );
 101       glVertex3f( r1*cos(angle),      r1*sin(angle),      -width*0.5 );
 102    }
 103    glEnd();
 104
 105
 106    /* draw outward faces of teeth */
 107    glBegin( GL_QUAD_STRIP );
 108    for (i=0;i<teeth;i++) {
 109       angle = i * 2.0*M_PI / teeth;
 110
 111       glVertex3f( r1*cos(angle),      r1*sin(angle),       width*0.5 );
 112       glVertex3f( r1*cos(angle),      r1*sin(angle),      -width*0.5 );
 113       u = r2*cos(angle+da) - r1*cos(angle);
 114       v = r2*sin(angle+da) - r1*sin(angle);
 115       len = sqrt( u*u + v*v );
 116       u /= len;
 117       v /= len;
 118       glNormal3f( v, -u, 0.0 );
 119       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),    width*0.5 );
 120       glVertex3f( r2*cos(angle+da),   r2*sin(angle+da),   -width*0.5 );
 121       glNormal3f( cos(angle), sin(angle), 0.0 );
 122       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da),  width*0.5 );
 123       glVertex3f( r2*cos(angle+2*da), r2*sin(angle+2*da), -width*0.5 );
 124       u = r1*cos(angle+3*da) - r2*cos(angle+2*da);
 125       v = r1*sin(angle+3*da) - r2*sin(angle+2*da);
 126       glNormal3f( v, -u, 0.0 );
 127       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da),  width*0.5 );
 128       glVertex3f( r1*cos(angle+3*da), r1*sin(angle+3*da), -width*0.5 );
 129       glNormal3f( cos(angle), sin(angle), 0.0 );
 130    }
 131
 132    glVertex3f( r1*cos(0), r1*sin(0), width*0.5 );
 133    glVertex3f( r1*cos(0), r1*sin(0), -width*0.5 );
 134
 135    glEnd();
 136
 137
 138    glShadeModel( GL_SMOOTH );
 139
 140    /* draw inside radius cylinder */
 141    glBegin( GL_QUAD_STRIP );
 142    for (i=0;i<=teeth;i++) {
 143       angle = i * 2.0*M_PI / teeth;
 144       glNormal3f( -cos(angle), -sin(angle), 0.0 );
 145       glVertex3f( r0*cos(angle), r0*sin(angle), -width*0.5 );
 146       glVertex3f( r0*cos(angle), r0*sin(angle), width*0.5 );
 147    }
 148    glEnd();
 149
 150 }
 151
 152
 153 static GLfloat view_rotx=20.0, view_roty=30.0, view_rotz=0.0;
 154 static GLint gear1, gear2, gear3;
 155 static GLfloat angle = 0.0;
 156
 157 static GLuint limit;
 158 static GLuint count = 1;
 159
 160
 161 static void draw( void )
 162 {
 163    angle += 2.0;
 164
 165    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 166
 167    glPushMatrix();
 168    glRotatef( view_rotx, 1.0, 0.0, 0.0 );
 169    glRotatef( view_roty, 0.0, 1.0, 0.0 );
 170    glRotatef( view_rotz, 0.0, 0.0, 1.0 );
 171
 172    glPushMatrix();
 173    glTranslatef( -3.0, -2.0, 0.0 );
 174    glRotatef( angle, 0.0, 0.0, 1.0 );
 175    glCallList(gear1);
 176    glPopMatrix();
 177
 178    glPushMatrix();
 179    glTranslatef( 3.1, -2.0, 0.0 );
 180    glRotatef( -2.0*angle-9.0, 0.0, 0.0, 1.0 );
 181    glCallList(gear2);
 182    glPopMatrix();
 183
 184    glPushMatrix();
 185    glTranslatef( -3.1, 4.2, 0.0 );
 186    glRotatef( -2.0*angle-25.0, 0.0, 0.0, 1.0 );
 187    glCallList(gear3);
 188    glPopMatrix();
 189
 190    glPopMatrix();
 191
 192    SVGAMesaSwapBuffers();
 193 }
 194
 195
 196 static void init( void )
 197 {
 198    static GLfloat pos[4] = {5.0, 5.0, 10.0, 1.0 };
 199    static GLfloat red[4] = {0.8, 0.1, 0.0, 1.0 };
 200    static GLfloat green[4] = {0.0, 0.8, 0.2, 1.0 };
 201    static GLfloat blue[4] = {0.2, 0.2, 1.0, 1.0 };
 202
 203    GLfloat w = (float) width / (float) height;
 204    GLfloat h = 1.0;
 205
 206    glLightfv( GL_LIGHT0, GL_POSITION, pos );
 207    glEnable( GL_CULL_FACE );
 208    glEnable( GL_LIGHTING );
 209    glEnable( GL_LIGHT0 );
 210    glEnable( GL_DEPTH_TEST );
 211
 212    /* make the gears */
 213    gear1 = glGenLists(1);
 214    glNewList(gear1, GL_COMPILE);
 215    glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, red );
 216    gear( 1.0, 4.0, 1.0, 20, 0.7 );
 217    glEndList();
 218
 219    gear2 = glGenLists(1);
 220    glNewList(gear2, GL_COMPILE);
 221    glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green );
 222    gear( 0.5, 2.0, 2.0, 10, 0.7 );
 223    glEndList();
 224
 225    gear3 = glGenLists(1);
 226    glNewList(gear3, GL_COMPILE);
 227    glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, blue );
 228    gear( 1.3, 2.0, 0.5, 10, 0.7 );
 229    glEndList();
 230
 231    glEnable( GL_NORMALIZE );
 232
 233
 234    glViewport( 0, 0, width, height );
 235    glMatrixMode(GL_PROJECTION);
 236    glLoadIdentity();
 237    if (width>height) {
 238       GLfloat w = (GLfloat) width / (GLfloat) height;
 239       glFrustum( -w, w, -1.0, 1.0, 5.0, 60.0 );
 240    }
 241    else {
 242       GLfloat h = (GLfloat) height / (GLfloat) width;
 243       glFrustum( -1.0, 1.0, -h, h, 5.0, 60.0 );
 244    }
 245
 246    glMatrixMode(GL_MODELVIEW);
 247    glLoadIdentity();
 248    glTranslatef( 0.0, 0.0, -40.0 );
 249 }
 250
 251 void setup( void )
 252 {
 253    vga_init();
 254
 255    vga_setmode(G800x600x32K);
 256 /*   gl_setcontextvga(G800x600x32K);*/
 257
 258    vmc = SVGAMesaCreateContext(GL_TRUE);
 259    SVGAMesaMakeCurrent( vmc );
 260 }
 261
 262
 263 void end( void )
 264 {
 265    SVGAMesaDestroyContext( vmc );
 266
 267    vga_setmode( TEXT );
 268 }
 269
 270
 271 int main( int argc, char *argv[] )
 272 {
 273    int i;
 274
 275    setup();
 276    init();
 277    for (i=0;i<4;i++) {
 278       draw(); /*SVGAMesaSwapBuffers();*/
 279    }
 280    end();
 281    return 0;
 282 }