progs/xdemos/shape.c

   1 /* $Id: shape.c,v 1.1 1999/08/19 00:55:43 jtg 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);
  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    glColor3f(1.0, 1.0, 1.0);
  57    glBegin(GL_LINE_LOOP);
  58    glVertex3f(-1.0, -1.0, -1.0);
  59    glVertex3f( 1.0, -1.0, -1.0);
  60    glVertex3f( 1.0,  1.0, -1.0);
  61    glVertex3f(-1.0,  1.0, -1.0);
  62    glEnd();
  63
  64    glBegin(GL_LINE_LOOP);
  65    glVertex3f(-1.0, -1.0, 1.0);
  66    glVertex3f( 1.0, -1.0, 1.0);
  67    glVertex3f( 1.0,  1.0, 1.0);
  68    glVertex3f(-1.0,  1.0, 1.0);
  69    glEnd();
  70
  71    glBegin(GL_LINES);
  72    glVertex3f(-1.0, -1.0, -1.0);   glVertex3f(-1.0, -1.0, 1.0);
  73    glVertex3f( 1.0, -1.0, -1.0);   glVertex3f( 1.0, -1.0, 1.0);
  74    glVertex3f( 1.0,  1.0, -1.0);   glVertex3f( 1.0,  1.0, 1.0);
  75    glVertex3f(-1.0,  1.0, -1.0);   glVertex3f(-1.0,  1.0, 1.0);
  76    glEnd();
  77
  78    glPopMatrix();
  79
  80    glXSwapBuffers(dpy, win);
  81 }
  82
  83
  84 /*
  85  * Called when no events are pending.
  86  */
  87 static void idle(void)
  88 {
  89    Xangle += 2.0;
  90    Yangle += 3.3;
  91    Redraw = 1;
  92 }
  93
  94
  95 /*
  96  * This is called when we have to recompute the window shape bitmask.
  97  * We just generate an n-sided regular polygon here but any other shape
  98  * would be possible.
  99  */
 100 static void make_shape_mask(Display *dpy, Window win, int width, int height,
 101                             int sides)
 102 {
 103    Pixmap shapeMask;
 104    XGCValues xgcv;
 105    GC gc;
 106
 107    /* allocate 1-bit deep pixmap and a GC */
 108    shapeMask = XCreatePixmap(dpy, win, width, height, 1);
 109    gc = XCreateGC(dpy, shapeMask, 0, &xgcv);
 110
 111    /* clear shapeMask to zeros */
 112    XSetForeground(dpy, gc, 0);
 113    XFillRectangle(dpy, shapeMask, gc, 0, 0, width, height);
 114
 115    /* draw mask */
 116    XSetForeground(dpy, gc, 1);
 117    {
 118       int cx = width / 2;
 119       int cy = height / 2;
 120       float angle = 0.0;
 121       float step = 2.0 * PI / sides;
 122       float radius = width / 2;
 123       int i;
 124       XPoint points[100];
 125       for (i=0;i<sides;i++) {
 126          int x = cx + radius * sin(angle);
 127          int y = cy - radius * cos(angle);
 128          points[i].x = x;
 129          points[i].y = y;
 130          angle += step;
 131       }
 132       XFillPolygon(dpy, shapeMask, gc, points, sides, Convex, CoordModeOrigin);
 133    }
 134
 135    /* This is the only SHAPE extension call- simple! */
 136    XShapeCombineMask(dpy, win, ShapeBounding, 0, 0, shapeMask, ShapeSet);
 137
 138    XFreeGC(dpy, gc);
 139    XFreePixmap(dpy, shapeMask);
 140 }
 141
 142
 143 /*
 144  * Called when window is resized.  Do OpenGL viewport and projection stuff.
 145  */
 146 static void reshape(int width, int height)
 147 {
 148    glViewport(0, 0, width, height);
 149    glMatrixMode(GL_PROJECTION);
 150    glLoadIdentity();
 151    glFrustum(-1.0, 1.0, -1.0, 1.0, 3.0, 20.0);
 152    glMatrixMode(GL_MODELVIEW);
 153    glLoadIdentity();
 154    glTranslatef(0.0, 0.0, -10.0);
 155 }
 156
 157
 158 /*
 159  * Process X events.
 160  */
 161 static void event_loop(Display *dpy, Window win)
 162 {
 163    while (1) {
 164       XEvent event;
 165       if (XPending(dpy)) {
 166          XNextEvent(dpy, &event);
 167          switch (event.type) {
 168             case Expose:
 169                display(dpy, event.xexpose.window);
 170                break;
 171             case ConfigureNotify:
 172                Width = event.xconfigure.width;
 173                Height = event.xconfigure.height,
 174                make_shape_mask(dpy, win, Width, Height, Sides);
 175                reshape(Width, Height);
 176                break;
 177             case KeyPress:
 178                {
 179                   char buf[100];
 180                   KeySym keySym;
 181                   XComposeStatus stat;
 182                   XLookupString(&event.xkey, buf, sizeof(buf), &keySym, &stat);
 183                   switch (keySym) {
 184                      case XK_Escape:
 185                         exit(0);
 186                         break;
 187                      case XK_Up:
 188                         Sides++;
 189                         if (Sides>MaxSides) Sides = MaxSides;
 190                         make_shape_mask(dpy, win, Width, Height, Sides);
 191                         break;
 192                      case XK_Down:
 193                         Sides--;
 194                         if (Sides<MinSides) Sides = MinSides;
 195                         make_shape_mask(dpy, win, Width, Height, Sides);
 196                         break;
 197                   }
 198                }
 199                break;
 200             default:
 201                ;;
 202          }
 203       }
 204       else {
 205          idle();
 206          if (Redraw) {
 207             display(dpy, win);
 208             Redraw = 0;
 209          }
 210       }
 211    }
 212 }
 213
 214
 215 /*
 216  * Allocate a "nice" colormap.  This could be better (HP-CR support, etc).
 217  */
 218 static Colormap alloc_colormap(Display *dpy, Window parent, Visual *vis)
 219 {
 220    Screen *scr = DefaultScreenOfDisplay(dpy);
 221    int scrnum = DefaultScreen(dpy);
 222
 223    if (MaxCmapsOfScreen(scr)==1 && vis==DefaultVisual(dpy, scrnum)) {
 224       /* The window and root are of the same visual type so */
 225       /* share the root colormap. */
 226       return DefaultColormap(dpy, scrnum);
 227    }
 228    else {
 229       return XCreateColormap(dpy, parent, vis, AllocNone);
 230    }
 231 }
 232
 233
 234 int main(int argc, char *argv[])
 235 {
 236    static int glAttribs[] = {
 237       GLX_DOUBLEBUFFER,
 238       GLX_RGBA,
 239       GLX_DEPTH_SIZE, 1,
 240       None
 241    };
 242    Display *dpy;
 243    XVisualInfo *visInfo;
 244    int scrn;
 245    Window root;
 246    Colormap cmap;
 247    Window win;
 248    XSetWindowAttributes winAttribs;
 249    unsigned long winAttribsMask;
 250    GLXContext glCtx;
 251    int ignore;
 252
 253    dpy = XOpenDisplay(NULL);
 254    if (!dpy) {
 255       fprintf(stderr, "Couldn't open default display\n");
 256       return 1;
 257    }
 258
 259    /* check that we can use the shape extension */
 260    if (!XQueryExtension(dpy, "SHAPE", &ignore, &ignore, &ignore )) {
 261       fprintf(stderr, "Display doesn't support shape extension\n");
 262       return 1;
 263    }
 264
 265    scrn = DefaultScreen(dpy);
 266
 267    root = RootWindow(dpy, scrn);
 268
 269    visInfo = glXChooseVisual(dpy, scrn, glAttribs);
 270    if (!visInfo) {
 271       fprintf(stderr, "Couldn't get RGB, DB, Z visual\n");
 272       return 1;
 273    }
 274
 275    glCtx = glXCreateContext(dpy, visInfo, 0, True);
 276    if (!glCtx) {
 277       fprintf(stderr, "Couldn't create GL context\n");
 278       return 1;
 279    }
 280
 281    cmap = alloc_colormap(dpy, root, visInfo->visual);
 282    if (!cmap) {
 283       fprintf(stderr, "Couln't create colormap\n");
 284       return 1;
 285    }
 286
 287    winAttribs.border_pixel = 0;
 288    winAttribs.colormap = cmap;
 289    winAttribs.event_mask = StructureNotifyMask | ExposureMask | KeyPressMask;
 290    winAttribsMask = CWBorderPixel | CWColormap | CWEventMask;
 291    win = XCreateWindow(dpy, root, 0, 0, Width, Height, 0,
 292                        visInfo->depth, InputOutput,
 293                        visInfo->visual,
 294                        winAttribsMask, &winAttribs);
 295    XMapWindow(dpy, win);
 296
 297    glXMakeCurrent(dpy, win, glCtx);
 298
 299    printf("Press ESC to exit.\n");
 300    printf("Press up/down to change window shape.\n");
 301
 302    event_loop(dpy, win);
 303
 304    return 0;
 305 }