progs/xdemos/shape.c

   1 /* $Id: shape.c,v 1.3 2000/06/27 15:34:35 brianp Exp $ */
   2
   3 /*
   4  * Example of using the X "shape" extension with OpenGL:  render a spinning
   5  * cube inside of a non-rectangular window.
   6  *
   7  * Press ESC to exit.  Press up/down to change window shape.
   8  *
   9  * To compile add "shape" to the PROGS list in Makefile.
  10  *
  11  * Brian Paul
  12  * June 16, 1997
  13  *
  14  * This program is in the public domain.
  15  */
  16
  17
  18 #include <math.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <X11/Xlib.h>
  22 #include <X11/Xutil.h>
  23 #include <X11/keysym.h>
  24 #include <X11/extensions/shape.h>
  25 #include <GL/glx.h>
  26
  27 #ifndef PI
  28 #define PI 3.1415926
  29 #endif
  30
  31
  32 static int Width=500, Height=500;
  33
  34 static float Xangle = 0.0, Yangle = 0.0;
  35 static int Redraw = 0;
  36 static int Sides = 5;
  37 static int MinSides = 3;
  38 static int MaxSides = 20;
  39
  40
  41 /*
  42  * Draw the OpenGL stuff and do a SwapBuffers.
  43  */
  44 static void display(Display *dpy, Window win)
  45 {
  46    float scale = 1.7;
  47
  48    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  49
  50    glPushMatrix();
  51
  52    glScalef(scale, scale, scale);
  53    glRotatef(Xangle, 1.0, 0.0, 0.0);
  54    glRotatef(Yangle, 0.0, 1.0, 0.0);
  55
  56    /*
  57     * wireframe box
  58     */
  59    glColor3f(1.0, 1.0, 1.0);
  60    glBegin(GL_LINE_LOOP);
  61    glVertex3f(-1.0, -1.0, -1.0);
  62    glVertex3f( 1.0, -1.0, -1.0);
  63    glVertex3f( 1.0,  1.0, -1.0);
  64    glVertex3f(-1.0,  1.0, -1.0);
  65    glEnd();
  66
  67    glBegin(GL_LINE_LOOP);
  68    glVertex3f(-1.0, -1.0, 1.0);
  69    glVertex3f( 1.0, -1.0, 1.0);
  70    glVertex3f( 1.0,  1.0, 1.0);
  71    glVertex3f(-1.0,  1.0, 1.0);
  72    glEnd();
  73
  74    glBegin(GL_LINES);
  75    glVertex3f(-1.0, -1.0, -1.0);   glVertex3f(-1.0, -1.0, 1.0);
  76    glVertex3f( 1.0, -1.0, -1.0);   glVertex3f( 1.0, -1.0, 1.0);
  77    glVertex3f( 1.0,  1.0, -1.0);   glVertex3f( 1.0,  1.0, 1.0);
  78    glVertex3f(-1.0,  1.0, -1.0);   glVertex3f(-1.0,  1.0, 1.0);
  79    glEnd();
  80
  81    /*
  82     * Solid box
  83     */
  84    glPushMatrix();
  85    glScalef(0.75, 0.75, 0.75);
  86
  87    glColor3f(1, 0, 0);
  88    glBegin(GL_POLYGON);
  89    glVertex3f(1, -1, -1);
  90    glVertex3f(1,  1, -1);
  91    glVertex3f(1,  1,  1);
  92    glVertex3f(1, -1,  1);
  93    glEnd();
  94
  95    glColor3f(0, 1, 1);
  96    glBegin(GL_POLYGON);
  97    glVertex3f(-1, -1, -1);
  98    glVertex3f(-1,  1, -1);
  99    glVertex3f(-1,  1,  1);
 100    glVertex3f(-1, -1,  1);
 101    glEnd();
 102
 103    glColor3f(0, 1, 0);
 104    glBegin(GL_POLYGON);
 105    glVertex3f(-1, 1, -1);
 106    glVertex3f( 1, 1, -1);
 107    glVertex3f( 1, 1,  1);
 108    glVertex3f(-1, 1,  1);
 109    glEnd();
 110
 111    glColor3f(1, 0, 1);
 112    glBegin(GL_POLYGON);
 113    glVertex3f(-1, -1, -1);
 114    glVertex3f( 1, -1, -1);
 115    glVertex3f( 1, -1,  1);
 116    glVertex3f(-1, -1,  1);
 117    glEnd();
 118
 119    glColor3f(0, 0, 1);
 120    glBegin(GL_POLYGON);
 121    glVertex3f(-1, -1, 1);
 122    glVertex3f( 1, -1, 1);
 123    glVertex3f( 1,  1, 1);
 124    glVertex3f(-1,  1, 1);
 125    glEnd();
 126
 127    glColor3f(1, 1, 0);
 128    glBegin(GL_POLYGON);
 129    glVertex3f(-1, -1, -1);
 130    glVertex3f( 1, -1, -1);
 131    glVertex3f( 1,  1, -1);
 132    glVertex3f(-1,  1, -1);
 133    glEnd();
 134    glPopMatrix();
 135
 136
 137    glPopMatrix();
 138
 139    glXSwapBuffers(dpy, win);
 140 }
 141
 142
 143 /*
 144  * Called when no events are pending.
 145  */
 146 static void idle(void)
 147 {
 148    Xangle += 2.0;
 149    Yangle += 3.3;
 150    Redraw = 1;
 151 }
 152
 153
 154 /*
 155  * This is called when we have to recompute the window shape bitmask.
 156  * We just generate an n-sided regular polygon here but any other shape
 157  * would be possible.
 158  */
 159 static void make_shape_mask(Display *dpy, Window win, int width, int height,
 160                             int sides)
 161 {
 162    Pixmap shapeMask;
 163    XGCValues xgcv;
 164    GC gc;
 165
 166    /* allocate 1-bit deep pixmap and a GC */
 167    shapeMask = XCreatePixmap(dpy, win, width, height, 1);
 168    gc = XCreateGC(dpy, shapeMask, 0, &xgcv);
 169
 170    /* clear shapeMask to zeros */
 171    XSetForeground(dpy, gc, 0);
 172    XFillRectangle(dpy, shapeMask, gc, 0, 0, width, height);
 173
 174    /* draw mask */
 175    XSetForeground(dpy, gc, 1);
 176    {
 177       int cx = width / 2;
 178       int cy = height / 2;
 179       float angle = 0.0;
 180       float step = 2.0 * PI / sides;
 181       float radius = width / 2;
 182       int i;
 183       XPoint points[100];
 184       for (i=0;i<sides;i++) {
 185          int x = cx + radius * sin(angle);
 186          int y = cy - radius * cos(angle);
 187          points[i].x = x;
 188          points[i].y = y;
 189          angle += step;
 190       }
 191       XFillPolygon(dpy, shapeMask, gc, points, sides, Convex, CoordModeOrigin);
 192    }
 193
 194    /* This is the only SHAPE extension call- simple! */
 195    XShapeCombineMask(dpy, win, ShapeBounding, 0, 0, shapeMask, ShapeSet);
 196
 197    XFreeGC(dpy, gc);
 198    XFreePixmap(dpy, shapeMask);
 199 }
 200
 201
 202 /*
 203  * Called when window is resized.  Do OpenGL viewport and projection stuff.
 204  */
 205 static void reshape(int width, int height)
 206 {
 207    glViewport(0, 0, width, height);
 208    glMatrixMode(GL_PROJECTION);
 209    glLoadIdentity();
 210    glFrustum(-1.0, 1.0, -1.0, 1.0, 3.0, 20.0);
 211    glMatrixMode(GL_MODELVIEW);
 212    glLoadIdentity();
 213    glTranslatef(0.0, 0.0, -10.0);
 214
 215    glEnable(GL_DEPTH_TEST);
 216 }
 217
 218
 219 /*
 220  * Process X events.
 221  */
 222 static void event_loop(Display *dpy, Window win)
 223 {
 224    while (1) {
 225       XEvent event;
 226       if (XPending(dpy)) {
 227          XNextEvent(dpy, &event);
 228          switch (event.type) {
 229             case Expose:
 230                display(dpy, event.xexpose.window);
 231                break;
 232             case ConfigureNotify:
 233                Width = event.xconfigure.width;
 234                Height = event.xconfigure.height,
 235                make_shape_mask(dpy, win, Width, Height, Sides);
 236                reshape(Width, Height);
 237                break;
 238             case KeyPress:
 239                {
 240                   char buf[100];
 241                   KeySym keySym;
 242                   XComposeStatus stat;
 243                   XLookupString(&event.xkey, buf, sizeof(buf), &keySym, &stat);
 244                   switch (keySym) {
 245                      case XK_Escape:
 246                         exit(0);
 247                         break;
 248                      case XK_Up:
 249                         Sides++;
 250                         if (Sides>MaxSides) Sides = MaxSides;
 251                         make_shape_mask(dpy, win, Width, Height, Sides);
 252                         break;
 253                      case XK_Down:
 254                         Sides--;
 255                         if (Sides<MinSides) Sides = MinSides;
 256                         make_shape_mask(dpy, win, Width, Height, Sides);
 257                         break;
 258                   }
 259                }
 260                break;
 261             default:
 262                ;;
 263          }
 264       }
 265       else {
 266          idle();
 267          if (Redraw) {
 268             display(dpy, win);
 269             Redraw = 0;
 270          }
 271       }
 272    }
 273 }
 274
 275
 276 /*
 277  * Allocate a "nice" colormap.  This could be better (HP-CR support, etc).
 278  */
 279 static Colormap alloc_colormap(Display *dpy, Window parent, Visual *vis)
 280 {
 281    Screen *scr = DefaultScreenOfDisplay(dpy);
 282    int scrnum = DefaultScreen(dpy);
 283
 284    if (MaxCmapsOfScreen(scr)==1 && vis==DefaultVisual(dpy, scrnum)) {
 285       /* The window and root are of the same visual type so */
 286       /* share the root colormap. */
 287       return DefaultColormap(dpy, scrnum);
 288    }
 289    else {
 290       return XCreateColormap(dpy, parent, vis, AllocNone);
 291    }
 292 }
 293
 294
 295 int main(int argc, char *argv[])
 296 {
 297    static int glAttribs[] = {
 298       GLX_DOUBLEBUFFER,
 299       GLX_RGBA,
 300       GLX_DEPTH_SIZE, 1,
 301       None
 302    };
 303    Display *dpy;
 304    XVisualInfo *visInfo;
 305    int scrn;
 306    Window root;
 307    Colormap cmap;
 308    Window win;
 309    XSetWindowAttributes winAttribs;
 310    unsigned long winAttribsMask;
 311    GLXContext glCtx;
 312    int ignore;
 313    const char *name = "OpenGL in a Shaped Window";
 314
 315    dpy = XOpenDisplay(NULL);
 316    if (!dpy) {
 317       fprintf(stderr, "Couldn't open default display\n");
 318       return 1;
 319    }
 320
 321    /* check that we can use the shape extension */
 322    if (!XQueryExtension(dpy, "SHAPE", &ignore, &ignore, &ignore )) {
 323       fprintf(stderr, "Display doesn't support shape extension\n");
 324       return 1;
 325    }
 326
 327    scrn = DefaultScreen(dpy);
 328
 329    root = RootWindow(dpy, scrn);
 330
 331    visInfo = glXChooseVisual(dpy, scrn, glAttribs);
 332    if (!visInfo) {
 333       fprintf(stderr, "Couldn't get RGB, DB, Z visual\n");
 334       return 1;
 335    }
 336
 337    glCtx = glXCreateContext(dpy, visInfo, 0, True);
 338    if (!glCtx) {
 339       fprintf(stderr, "Couldn't create GL context\n");
 340       return 1;
 341    }
 342
 343    cmap = alloc_colormap(dpy, root, visInfo->visual);
 344    if (!cmap) {
 345       fprintf(stderr, "Couln't create colormap\n");
 346       return 1;
 347    }
 348
 349    winAttribs.border_pixel = 0;
 350    winAttribs.colormap = cmap;
 351    winAttribs.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
 352    winAttribsMask = CWBorderPixel | CWColormap | CWEventMask;
 353    win = XCreateWindow(dpy, root, 0, 0, Width, Height, 0,
 354                        visInfo->depth, InputOutput,
 355                        visInfo->visual,
 356                        winAttribsMask, &winAttribs);
 357
 358    {
 359       XSizeHints sizehints;
 360       /*
 361       sizehints.x = xpos;
 362       sizehints.y = ypos;
 363       sizehints.width  = width;
 364       sizehints.height = height;
 365       */
 366       sizehints.flags = 0;
 367       XSetNormalHints(dpy, win, &sizehints);
 368       XSetStandardProperties(dpy, win, name, name,
 369                               None, (char **)NULL, 0, &sizehints);
 370    }
 371
 372
 373    XMapWindow(dpy, win);
 374
 375    glXMakeCurrent(dpy, win, glCtx);
 376
 377    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 378    printf("Press ESC to exit.\n");
 379    printf("Press up/down to change window shape.\n");
 380
 381    event_loop(dpy, win);
 382
 383    return 0;
 384 }