src/xdemos/xdemo.c

   1
   2 /*
   3  * Very simple demo of how to use the Mesa/X11 interface instead of the
   4  * glx, tk or aux toolkits.  I highly recommend using the GLX interface
   5  * instead of the X/Mesa interface, however.
   6  *
   7  * This program is in the public domain.
   8  *
   9  * Brian Paul
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <X11/Xlib.h>
  16 #include <X11/Xutil.h>
  17 #include "GL/xmesa.h"
  18 #include "GL/gl.h"
  19
  20
  21
  22 static GLint Black, Red, Green, Blue;
  23
  24
  25
  26 static void make_window( char *title, int color_flag )
  27 {
  28    int x = 10, y = 10, width = 400, height = 300;
  29    Display *dpy;
  30    int scr;
  31    Window root, win;
  32    Colormap cmap;
  33    XColor xcolor;
  34    int attr_flags;
  35    XVisualInfo *visinfo;
  36    XSetWindowAttributes attr;
  37    XTextProperty tp;
  38    XSizeHints sh;
  39    XEvent e;
  40    XMesaContext context;
  41    XMesaVisual visual;
  42    XMesaBuffer buffer;
  43
  44
  45    /*
  46     * Do the usual X things to make a window.
  47     */
  48
  49    dpy = XOpenDisplay(NULL);
  50    if (!dpy) {
  51       printf("Couldn't open default display!\n");
  52       exit(1);
  53    }
  54
  55    scr = DefaultScreen(dpy);
  56    root = RootWindow(dpy, scr);
  57
  58    /* alloc visinfo struct */
  59    visinfo = (XVisualInfo *) malloc( sizeof(XVisualInfo) );
  60
  61    /* Get a visual and colormap */
  62    if (color_flag) {
  63       /* Open TrueColor window */
  64
  65 /*
  66       if (!XMatchVisualInfo( dpy, scr, 24, TrueColor, visinfo )) {
  67          printf("Couldn't get 24-bit TrueColor visual!\n");
  68          exit(1);
  69       }
  70 */
  71       if (!XMatchVisualInfo( dpy, scr, 8, PseudoColor, visinfo )) {
  72          printf("Couldn't get 8-bit PseudoColor visual!\n");
  73          exit(1);
  74       }
  75
  76       cmap = XCreateColormap( dpy, root, visinfo->visual, AllocNone );
  77       Black = Red = Green = Blue = 0;
  78    }
  79    else {
  80       /* Open color index window */
  81
  82       if (!XMatchVisualInfo( dpy, scr, 8, PseudoColor, visinfo )) {
  83          printf("Couldn't get 8-bit PseudoColor visual\n");
  84          exit(1);
  85       }
  86
  87       cmap = XCreateColormap( dpy, root, visinfo->visual, AllocNone );
  88
  89       /* Allocate colors */
  90       xcolor.red   = 0x0;
  91       xcolor.green = 0x0;
  92       xcolor.blue  = 0x0;
  93       xcolor.flags = DoRed | DoGreen | DoBlue;
  94       if (!XAllocColor( dpy, cmap, &xcolor )) {
  95          printf("Couldn't allocate black!\n");
  96          exit(1);
  97       }
  98       Black = xcolor.pixel;
  99
 100       xcolor.red   = 0xffff;
 101       xcolor.green = 0x0;
 102       xcolor.blue  = 0x0;
 103       xcolor.flags = DoRed | DoGreen | DoBlue;
 104       if (!XAllocColor( dpy, cmap, &xcolor )) {
 105          printf("Couldn't allocate red!\n");
 106          exit(1);
 107       }
 108       Red = xcolor.pixel;
 109
 110       xcolor.red   = 0x0;
 111       xcolor.green = 0xffff;
 112       xcolor.blue  = 0x0;
 113       xcolor.flags = DoRed | DoGreen | DoBlue;
 114       if (!XAllocColor( dpy, cmap, &xcolor )) {
 115          printf("Couldn't allocate green!\n");
 116          exit(1);
 117       }
 118       Green = xcolor.pixel;
 119
 120       xcolor.red   = 0x0;
 121       xcolor.green = 0x0;
 122       xcolor.blue  = 0xffff;
 123       xcolor.flags = DoRed | DoGreen | DoBlue;
 124       if (!XAllocColor( dpy, cmap, &xcolor )) {
 125          printf("Couldn't allocate blue!\n");
 126          exit(1);
 127       }
 128       Blue = xcolor.pixel;
 129    }
 130
 131    /* set window attributes */
 132    attr.colormap = cmap;
 133    attr.event_mask = ExposureMask | StructureNotifyMask;
 134    attr.border_pixel = BlackPixel( dpy, scr );
 135    attr.background_pixel = BlackPixel( dpy, scr );
 136    attr_flags = CWColormap | CWEventMask | CWBorderPixel | CWBackPixel;
 137
 138    /* Create the window */
 139    win = XCreateWindow( dpy, root, x,y, width, height, 0,
 140                             visinfo->depth, InputOutput,
 141                             visinfo->visual,
 142                             attr_flags, &attr);
 143    if (!win) {
 144       printf("Couldn't open window!\n");
 145       exit(1);
 146    }
 147
 148    XStringListToTextProperty(&title, 1, &tp);
 149    sh.flags = USPosition | USSize;
 150    XSetWMProperties(dpy, win, &tp, &tp, 0, 0, &sh, 0, 0);
 151    XMapWindow(dpy, win);
 152    while (1) {
 153       XNextEvent( dpy, &e );
 154       if (e.type == MapNotify && e.xmap.window == win) {
 155          break;
 156       }
 157    }
 158
 159
 160    /*
 161     * Now do the special Mesa/Xlib stuff!
 162     */
 163
 164    visual = XMesaCreateVisual( dpy, visinfo,
 165                               (GLboolean) color_flag,
 166                                GL_FALSE,  /* alpha_flag */
 167                                GL_FALSE,  /* db_flag */
 168                                GL_FALSE,  /* stereo flag */
 169                                GL_FALSE,  /* ximage_flag */
 170                                0,         /* depth size */
 171                                0,         /* stencil size */
 172                                0,0,0,0,   /* accum_size */
 173                                0,         /* num samples */
 174                                0,         /* level */
 175                                0          /* caveat */
 176                               );
 177    if (!visual) {
 178       printf("Couldn't create Mesa/X visual!\n");
 179       exit(1);
 180    }
 181
 182    /* Create a Mesa rendering context */
 183    context = XMesaCreateContext( visual,
 184                                  NULL       /* share_list */
 185                                );
 186    if (!context) {
 187       printf("Couldn't create Mesa/X context!\n");
 188       exit(1);
 189    }
 190
 191    buffer = XMesaCreateWindowBuffer( visual, win );
 192    if (!buffer) {
 193       printf("Couldn't create Mesa/X buffer!\n");
 194       exit(1);
 195    }
 196
 197
 198    XMesaMakeCurrent( context, buffer );
 199
 200    /* Ready to render! */
 201 }
 202
 203
 204
 205 static void draw_cube( void )
 206 {
 207    /* X faces */
 208    glIndexi( Red );
 209    glColor3f( 1.0, 0.0, 0.0 );
 210    glBegin( GL_POLYGON );
 211    glVertex3f( 1.0, 1.0, 1.0 );
 212    glVertex3f( 1.0, -1.0, 1.0 );
 213    glVertex3f( 1.0, -1.0, -1.0 );
 214    glVertex3f( 1.0, 1.0, -1.0 );
 215    glEnd();
 216
 217    glBegin( GL_POLYGON );
 218    glVertex3f( -1.0, 1.0, 1.0 );
 219    glVertex3f( -1.0, 1.0, -1.0 );
 220    glVertex3f( -1.0, -1.0, -1.0 );
 221    glVertex3f( -1.0, -1.0, 1.0 );
 222    glEnd();
 223
 224    /* Y faces */
 225    glIndexi( Green );
 226    glColor3f( 0.0, 1.0, 0.0 );
 227    glBegin( GL_POLYGON );
 228    glVertex3f(  1.0, 1.0,  1.0 );
 229    glVertex3f(  1.0, 1.0, -1.0 );
 230    glVertex3f( -1.0, 1.0, -1.0 );
 231    glVertex3f( -1.0, 1.0,  1.0 );
 232    glEnd();
 233
 234    glBegin( GL_POLYGON );
 235    glVertex3f(  1.0, -1.0,  1.0 );
 236    glVertex3f( -1.0, -1.0,  1.0 );
 237    glVertex3f( -1.0, -1.0, -1.0 );
 238    glVertex3f(  1.0, -1.0, -1.0 );
 239    glEnd();
 240
 241    /* Z faces */
 242    glIndexi( Blue );
 243    glColor3f( 0.0, 0.0, 1.0 );
 244    glBegin( GL_POLYGON );
 245    glVertex3f(  1.0,  1.0,  1.0 );
 246    glVertex3f( -1.0,  1.0,  1.0 );
 247    glVertex3f( -1.0, -1.0,  1.0 );
 248    glVertex3f(  1.0, -1.0,  1.0 );
 249    glEnd();
 250
 251    glBegin( GL_POLYGON );
 252    glVertex3f(  1.0, 1.0, -1.0 );
 253    glVertex3f(  1.0,-1.0, -1.0 );
 254    glVertex3f( -1.0,-1.0, -1.0 );
 255    glVertex3f( -1.0, 1.0, -1.0 );
 256    glEnd();
 257 }
 258
 259
 260
 261
 262 static void display_loop( void )
 263 {
 264    GLfloat xrot, yrot, zrot;
 265
 266    xrot = yrot = zrot = 0.0;
 267
 268    glClearColor( 0.0, 0.0, 0.0, 0.0 );
 269    glClearIndex( Black );
 270
 271    glMatrixMode( GL_PROJECTION );
 272    glLoadIdentity();
 273    glFrustum( -1.0, 1.0,  -1.0, 1.0,  1.0, 10.0 );
 274    glTranslatef( 0.0, 0.0, -5.0 );
 275
 276    glMatrixMode( GL_MODELVIEW );
 277    glLoadIdentity();
 278
 279    glCullFace( GL_BACK );
 280    glEnable( GL_CULL_FACE );
 281
 282    glShadeModel( GL_FLAT );
 283
 284    while (1) {
 285       glClear( GL_COLOR_BUFFER_BIT );
 286       glPushMatrix();
 287       glRotatef( xrot, 1.0, 0.0, 0.0 );
 288       glRotatef( yrot, 0.0, 1.0, 0.0 );
 289       glRotatef( zrot, 0.0, 0.0, 1.0 );
 290
 291       draw_cube();
 292
 293       glPopMatrix();
 294       glFinish();
 295
 296       xrot += 10.0;
 297       yrot += 7.0;
 298       zrot -= 3.0;
 299    }
 300
 301 }
 302
 303
 304
 305
 306 int main( int argc, char *argv[] )
 307 {
 308    int mode = 0;
 309
 310    if (argc >= 2)
 311    {
 312         if (strcmp(argv[1],"-ci")==0)
 313            mode = 0;
 314         else if (strcmp(argv[1],"-rgb")==0)
 315            mode = 1;
 316         else
 317         {
 318            printf("Bad flag: %s\n", argv[1]);
 319            printf("Specify -ci for 8-bit color index or -rgb for RGB mode\n");
 320            exit(1);
 321         }
 322    }
 323    else
 324    {
 325         printf("Specify -ci for 8-bit color index or -rgb for RGB mode\n");
 326         printf("Defaulting to  8-bit color index\n");
 327    }
 328
 329    make_window( argv[0], mode );
 330
 331    display_loop();
 332    return 0;
 333 }
 334