git.hungrycats.org Git - xscreensaver/blob - hacks/distort.c

   1 /* -*- mode: C; tab-width: 4 -*-
   2  * xscreensaver, Copyright (c) 1992, 1993, 1994, 1996, 1997, 1998
   3  * Jamie Zawinski <jwz@jwz.org>
   4  *
   5  * Permission to use, copy, modify, distribute, and sell this software and its
   6  * documentation for any purpose is hereby granted without fee, provided that
   7  * the above copyright notice appear in all copies and that both that
   8  * copyright notice and this permission notice appear in supporting
   9  * documentation.  No representations are made about the suitability of this
  10  * software for any purpose.  It is provided "as is" without express or
  11  * implied warranty.
  12  */
  13
  14 /* distort
  15  * by Jonas Munsin (jmunsin@iki.fi) and Jamie Zawinski <jwz@jwz.org>
  16  * TODO:
  17  *      -check the allocations in init_round_lense again, maybe make it possible again
  18  *       to use swamp without pre-allocating/calculating (although that
  19  *       makes it slower) - -swamp is memory hungry
  20  *      -more distortion matrices (fortunately, I'm out of ideas :)
  21  * Stuff that would be cool but probably too much of a resource hog:
  22  *      -some kind of interpolation to avoid jaggies
  23  *    -large speed values leaves the image distorted
  24  * program idea borrowed from a screensaver on a non-*NIX OS,
  25  *
  26  * 28 Sep 1999 Jonas Munsin (jmunsin@iki.fi)
  27  *    Added about 10x faster algortim for 8, 16 and 32 bpp (modifies pixels
  28  *    directly avoiding costly XPutPixle(XGetPixel()) calls, inspired by
  29  *    xwhirl made by horvai@clipper.ens.fr (Peter Horvai) and the XFree86
  30  *    Xlib sources.
  31  *    This piece of code is really horrible, but it works, and at the moment
  32  *    I don't have time or inspiration to fix something that works (knock
  33  *    on wood).
  34  * 08 Oct 1999 Jonas Munsin (jmunsin@iki.fi)
  35  *      Corrected several bugs causing references beyond allocated memory.
  36  */
  37
  38 #include <math.h>
  39 #include "screenhack.h"
  40 #include <X11/Xutil.h>
  41 #include <X11/Xmd.h>
  42
  43 #ifdef HAVE_XSHM_EXTENSION
  44 # include "xshm.h"
  45 static Bool use_shm = False;
  46 static XShmSegmentInfo shm_info;
  47 #endif /* HAVE_XSHM_EXTENSION */
  48
  49 struct coo {
  50         int x;
  51         int y;
  52         int r, r_change;
  53         int xmove, ymove;
  54 };
  55 static struct coo xy_coo[10];
  56
  57 static int delay, radius, speed, number, blackhole, vortex, magnify, reflect, slow;
  58 static XWindowAttributes xgwa;
  59 static GC gc;
  60 static Window g_window;
  61 static Display *g_dpy;
  62 static unsigned long black_pixel;
  63
  64 static XImage *orig_map, *buffer_map;
  65 static unsigned long *buffer_map_cache;
  66
  67 static int ***from;
  68 static int ****from_array;
  69 static int *fast_from = NULL;
  70 static void (*effect) (int) = NULL;
  71 static void move_lense(int);
  72 static void swamp_thing(int);
  73 static void new_rnd_coo(int);
  74 static void init_round_lense(void);
  75 static void (*draw) (int) = NULL;
  76 static void reflect_draw(int);
  77 static void plain_draw(int);
  78
  79 static void (*draw_routine)(XImage *, XImage *, int, int, int *) = NULL;
  80 static void fast_draw_8(XImage *, XImage *, int, int, int *);
  81 static void fast_draw_16(XImage *, XImage *, int, int, int *);
  82 static void fast_draw_32(XImage *, XImage *, int, int, int *);
  83 static void generic_draw(XImage *, XImage *, int, int, int *);
  84 static int bpp_size = 0;
  85
  86
  87 static void init_distort(Display *dpy, Window window)
  88 {
  89         XGCValues gcv;
  90         long gcflags;
  91         int i;
  92
  93         g_window=window;
  94         g_dpy=dpy;
  95
  96         delay = get_integer_resource("delay", "Integer");
  97         radius = get_integer_resource("radius", "Integer");
  98         speed = get_integer_resource("speed", "Integer");
  99         number = get_integer_resource("number", "Integer");
 100
 101 #ifdef HAVE_XSHM_EXTENSION
 102         use_shm = get_boolean_resource("useSHM", "Boolean");
 103 #endif /* HAVE_XSHM_EXTENSION */
 104
 105         blackhole = get_boolean_resource("blackhole", "Boolean");
 106         vortex = get_boolean_resource("vortex", "Boolean");
 107         magnify = get_boolean_resource("magnify", "Boolean");
 108         reflect = get_boolean_resource("reflect", "Boolean");
 109         slow = get_boolean_resource("slow", "Boolean");
 110
 111         if (get_boolean_resource("swamp", "Boolean"))
 112                 effect = &swamp_thing;
 113         if (get_boolean_resource("bounce", "Boolean"))
 114                 effect = &move_lense;
 115
 116         if (effect == NULL && radius == 0 && speed == 0 && number == 0
 117                 && !blackhole && !vortex && !magnify && !reflect) {
 118 /* if no cmdline options are given, randomly choose one of:
 119  * -radius 50 -number 4 -speed 1 -bounce
 120  * -radius 50 -number 4 -speed 1 -blackhole
 121  * -radius 50 -number 4 -speed 1 -vortex
 122  * -radius 50 -number 4 -speed 1 -vortex -magnify
 123  * -radius 50 -number 4 -speed 1 -vortex -magnify -blackhole
 124  * -radius 100 -number 1 -speed 2 -bounce
 125  * -radius 100 -number 1 -speed 2 -blackhole
 126  * -radius 100 -number 1 -speed 2 -vortex
 127  * -radius 100 -number 1 -speed 2 -vortex -magnify
 128  * -radius 100 -number 1 -speed 2 -vortex -magnify -blackhole
 129  * -radius 80 -number 1 -speed 2 -reflect
 130  * -radius 50 -number 3 -speed 2 -reflect
 131  * jwz: not these
 132  *   -radius 50 -number 4 -speed 2 -swamp
 133  *   -radius 50 -number 4 -speed 2 -swamp -blackhole
 134  *   -radius 50 -number 4 -speed 2 -swamp -vortex
 135  *   -radius 50 -number 4 -speed 2 -swamp -vortex -magnify
 136  *   -radius 50 -number 4 -speed 2 -swamp -vortex -magnify -blackhole
 137  */
 138
 139                 i = (random() % 12 /* 17 */);
 140
 141                 draw = &plain_draw;
 142
 143                 switch (i) {
 144                         case 0:
 145                                 radius=50;number=4;speed=1;
 146                                 effect=&move_lense;break;
 147                         case 1:
 148                                 radius=50;number=4;speed=1;blackhole=1;
 149                                 effect=&move_lense;break;
 150                         case 2:
 151                                 radius=50;number=4;speed=1;vortex=1;
 152                                 effect=&move_lense;break;
 153                         case 3:
 154                                 radius=50;number=4;speed=1;vortex=1;magnify=1;
 155                                 effect=&move_lense;break;
 156                         case 4:
 157                                 radius=50;number=4;speed=1;vortex=1;magnify=1;blackhole=1;
 158                                 effect=&move_lense;break;
 159                         case 5:
 160                                 radius=100;number=1;speed=2;
 161                                 effect=&move_lense;break;
 162                         case 6:
 163                                 radius=100;number=1;speed=2;blackhole=1;
 164                                 effect=&move_lense;break;
 165                         case 7:
 166                                 radius=100;number=1;speed=2;vortex=1;
 167                                 effect=&move_lense;break;
 168                         case 8:
 169                                 radius=100;number=1;speed=2;vortex=1;magnify=1;
 170                                 effect=&move_lense;break;
 171                         case 9:
 172                                 radius=100;number=1;speed=2;vortex=1;magnify=1;blackhole=1;
 173                                 effect=&move_lense;break;
 174
 175                         case 10:
 176                                 radius=80;number=1;speed=2;reflect=1;
 177                                 draw = &reflect_draw;effect = &move_lense;break;
 178                         case 11:
 179                                 radius=50;number=4;speed=2;reflect=1;
 180                                 draw = &reflect_draw;effect = &move_lense;break;
 181
 182 #if 0 /* jwz: not these */
 183                         case 12:
 184                                 radius=50;number=4;speed=2;
 185                                 effect=&swamp_thing;break;
 186                         case 13:
 187                                 radius=50;number=4;speed=2;blackhole=1;
 188                                 effect=&swamp_thing;break;
 189                         case 14:
 190                                 radius=50;number=4;speed=2;vortex=1;
 191                                 effect=&swamp_thing;break;
 192                         case 15:
 193                                 radius=50;number=4;speed=2;vortex=1;magnify=1;
 194                                 effect=&swamp_thing;break;
 195                         case 16:
 196                                 radius=50;number=4;speed=2;vortex=1;magnify=1;blackhole=1;
 197                                 effect=&swamp_thing;break;
 198 #endif
 199
 200             default:
 201                 abort(); break;
 202                 }
 203
 204         }
 205
 206         if (delay < 0)
 207                 delay = 0;
 208         if (radius <= 0)
 209                 radius = 60;
 210         if (speed <= 0)
 211                 speed = 2;
 212         if (number <= 0)
 213                 number=1;
 214         if (number >= 10)
 215                 number=1;
 216         if (effect == NULL)
 217                 effect = &move_lense;
 218         if (reflect) {
 219                 draw = &reflect_draw;
 220                 effect = &move_lense;
 221         }
 222         if (draw == NULL)
 223                 draw = &plain_draw;
 224
 225         XGetWindowAttributes (dpy, window, &xgwa);
 226         black_pixel = BlackPixelOfScreen( xgwa.screen );
 227
 228         gcv.function = GXcopy;
 229         gcv.subwindow_mode = IncludeInferiors;
 230         gcflags = GCForeground |GCFunction;
 231         if (use_subwindow_mode_p(xgwa.screen, window)) /* see grabscreen.c */
 232                 gcflags |= GCSubwindowMode;
 233         gc = XCreateGC (dpy, window, gcflags, &gcv);
 234
 235         grab_screen_image (xgwa.screen, window);
 236
 237         buffer_map = 0;
 238         orig_map = XGetImage(dpy, window, 0, 0, xgwa.width, xgwa.height,
 239                                                  ~0L, ZPixmap);
 240         buffer_map_cache = malloc(sizeof(unsigned long)*(2*radius+speed+2)*(2*radius+speed+2));
 241
 242         if (buffer_map_cache == NULL) {
 243                 perror("distort");
 244                 exit(EXIT_FAILURE);
 245         }
 246
 247 # ifdef HAVE_XSHM_EXTENSION
 248
 249         if (use_shm)
 250           {
 251                 buffer_map = create_xshm_image(dpy, xgwa.visual, orig_map->depth,
 252                                                                            ZPixmap, 0, &shm_info,
 253                                                                            2*radius + speed + 2,
 254                                                                            2*radius + speed + 2);
 255                 if (!buffer_map)
 256                   use_shm = False;
 257           }
 258 # endif /* HAVE_XSHM_EXTENSION */
 259
 260         if (!buffer_map)
 261           {
 262                 buffer_map = XCreateImage(dpy, xgwa.visual,
 263                                                                   orig_map->depth, ZPixmap, 0, 0,
 264                                                                   2*radius + speed + 2, 2*radius + speed + 2,
 265                                                                   8, 0);
 266                 buffer_map->data = (char *)
 267                   calloc(buffer_map->height, buffer_map->bytes_per_line);
 268         }
 269
 270         if ((buffer_map->byte_order == orig_map->byte_order)
 271                         && (buffer_map->depth == orig_map->depth)
 272                         && (buffer_map->format == ZPixmap)
 273                         && (orig_map->format == ZPixmap)
 274                         && !slow) {
 275                 switch (orig_map->bits_per_pixel) {
 276                         case 32:
 277                                 draw_routine = &fast_draw_32;
 278                                 bpp_size = sizeof(CARD32);
 279                                 break;
 280                         case 16:
 281                                 draw_routine = &fast_draw_16;
 282                                 bpp_size = sizeof(CARD16);
 283                                 break;
 284                         case 8:
 285                                 draw_routine = &fast_draw_8;
 286                                 bpp_size = sizeof(CARD8);
 287                                 break;
 288                         default:
 289                                 draw_routine = &generic_draw;
 290                                 break;
 291                 }
 292         } else {
 293                 draw_routine = &generic_draw;
 294         }
 295         init_round_lense();
 296
 297         for (i = 0; i < number; i++) {
 298                 new_rnd_coo(i);
 299                 if (number != 1)
 300                         xy_coo[i].r = (i*radius)/(number-1); /* "randomize" initial */
 301                 else
 302                          xy_coo[i].r = 0;
 303                 xy_coo[i].r_change = speed + (i%2)*2*(-speed);  /* values a bit */
 304                 xy_coo[i].xmove = speed + (i%2)*2*(-speed);
 305                 xy_coo[i].ymove = speed + (i%2)*2*(-speed);
 306         }
 307
 308 }
 309
 310 /* example: initializes a "see-trough" matrix */
 311 /* static void make_null_lense(void)
 312 {
 313         int i, j;
 314         for (i = 0; i < 2*radius+speed+2; i++) {
 315                 for (j = 0 ; j < 2*radius+speed+2 ; j++) {
 316                         from[i][j][0]=i;
 317                         from[i][j][1]=j;
 318                 }
 319         }
 320 }
 321 */
 322 static void convert(void) {
 323         int *p;
 324         int i, j;
 325         fast_from = calloc(1, sizeof(int)*((buffer_map->bytes_per_line/bpp_size)*(2*radius+speed+2) + 2*radius+speed+2));
 326         if (fast_from == NULL) {
 327                 perror("distort");
 328                 exit(EXIT_FAILURE);
 329         }
 330         p = fast_from;
 331         for (i = 0; i < 2*radius+speed+2; i++) {
 332                 for (j = 0; j < 2*radius+speed+2; j++) {
 333                         *(p + i + j*buffer_map->bytes_per_line/bpp_size)
 334                                 = from[i][j][0] + xgwa.width*from[i][j][1];
 335                         if (*(p + i + j*buffer_map->bytes_per_line/bpp_size) < 0
 336                                         || *(p + i + j*buffer_map->bytes_per_line/bpp_size) >= orig_map->height*orig_map->width) {
 337                                 *(p + i + j*buffer_map->bytes_per_line/bpp_size) = 0;
 338                         }
 339                 }
 340         }
 341 }
 342
 343 /* makes a lense with the Radius=loop and centred in
 344  * the point (radius, radius)
 345  */
 346 static void make_round_lense(int radius, int loop)
 347 {
 348         int i, j;
 349
 350         for (i = 0; i < 2*radius+speed+2; i++) {
 351                 for(j = 0; j < ((0 == bpp_size) ? (2*radius+speed+2) : (buffer_map->bytes_per_line/bpp_size)); j++) {
 352                         double r, d;
 353                         r = sqrt ((i-radius)*(i-radius)+(j-radius)*(j-radius));
 354                         if (loop == 0)
 355                           d=0.0;
 356                         else
 357                           d=r/loop;
 358
 359                         if (r < loop-1) {
 360
 361                                 if (vortex) { /* vortex-twist effect */
 362                                         double angle;
 363                 /* this one-line formula for getting a nice rotation angle is borrowed
 364                  * (with permission) from the whirl plugin for gimp,
 365                  * Copyright (C) 1996 Federico Mena Quintero
 366                  */
 367                 /* 5 is just a constant used because it looks good :) */
 368                                         angle = 5*(1-d)*(1-d);
 369
 370         /* Avoid atan2: DOMAIN error message */
 371                                         if ((radius-j) == 0.0 && (radius-i) == 0.0) {
 372                                                 from[i][j][0] = radius + cos(angle)*r;
 373                                                 from[i][j][1] = radius + sin(angle)*r;
 374                                         } else {
 375                                                 from[i][j][0] = radius +
 376                                                         cos(angle - atan2(radius-j, -(radius-i)))*r;
 377                                                 from[i][j][1] = radius +
 378                                                         sin(angle - atan2(radius-j, -(radius-i)))*r;
 379                                         }
 380                                         if (magnify) {
 381                                                 r = sin(d*M_PI_2);
 382                                                 if (blackhole && r != 0) /* blackhole effect */
 383                                                         r = 1/r;
 384                                                 from[i][j][0] = radius + (from[i][j][0]-radius)*r;
 385                                                 from[i][j][1] = radius + (from[i][j][1]-radius)*r;
 386                                         }
 387                                 } else { /* default is to magnify */
 388                                         r = sin(d*M_PI_2);
 389
 390         /* raising r to different power here gives different amounts of
 391          * distortion, a negative value sucks everything into a black hole
 392          */
 393                                 /*      r = r*r; */
 394                                         if (blackhole && r != 0) /* blackhole effect */
 395                                                 r = 1/r;
 396                                                                         /* bubble effect (and blackhole) */
 397                                         from[i][j][0] = radius + (i-radius)*r;
 398                                         from[i][j][1] = radius + (j-radius)*r;
 399                                 }
 400                         } else { /* not inside loop */
 401                                 from[i][j][0] = i;
 402                                 from[i][j][1] = j;
 403                         }
 404                 }
 405         }
 406
 407         /* this is really just a quick hack to keep both the compability mode with all depths and still
 408          * allow the custom optimized draw routines with the minimum amount of work */
 409         if (0 != bpp_size) {
 410                 convert();
 411         }
 412 }
 413
 414 #ifndef EXIT_FAILURE
 415 # define EXIT_FAILURE -1
 416 #endif
 417
 418 static void allocate_lense(void)
 419 {
 420         int i, j;
 421         int s = ((0 != bpp_size) ? (buffer_map->bytes_per_line/bpp_size) : (2*radius+speed+2));
 422         /* maybe this should be redone so that from[][][] is in one block;
 423          * then pointers could be used instead of arrays in some places (and
 424          * maybe give a speedup - maybe also consume less memory)
 425          */
 426         from = (int ***)malloc(s*sizeof(int **));
 427         if (from == NULL) {
 428                 perror("distort");
 429                 exit(EXIT_FAILURE);
 430         }
 431         for (i = 0; i < s; i++) {
 432                 from[i] = (int **)malloc((2*radius+speed+2) * sizeof(int *));
 433                 if (from[i] == NULL) {
 434                         perror("distort");
 435                         exit(EXIT_FAILURE);
 436                 }
 437                 for (j = 0; j < s; j++) {
 438                         from[i][j] = (int *)malloc(2 * sizeof(int));
 439                         if (from[i][j] == NULL) {
 440                                 perror("distort");
 441                                 exit(EXIT_FAILURE);
 442                         }
 443                 }
 444         }
 445 }
 446
 447 /* from_array in an array containing precalculated from matrices,
 448  * this is a double faced mem vs speed trade, it's faster, but eats
 449  * _a lot_ of mem for large radius (is there a bug here? I can't see it)
 450  */
 451 static void init_round_lense(void)
 452 {
 453         int k;
 454
 455         if (effect == &swamp_thing) {
 456                 from_array = (int ****)malloc((radius+1)*sizeof(int ***));
 457                 for (k=0; k <= radius; k++) {
 458                         allocate_lense();
 459                         make_round_lense(radius, k);
 460                         from_array[k] = from;
 461                 }
 462         } else { /* just allocate one from[][][] */
 463                 allocate_lense();
 464                 make_round_lense(radius,radius);
 465         }
 466 }
 467
 468 /* If fast_draw_8, fast_draw_16 or fast_draw_32 are to be used, the following properties
 469  * of the src and dest XImages must hold (otherwise the generic, slooow, method provided
 470  * by X is to be used):
 471  *      src->byte_order == dest->byte_order
 472  *      src->format == ZPixmap && dest->format == ZPixmap
 473  *      src->depth == dest->depth == the depth the function in question asumes
 474  * x and y is the coordinates in src from where to cut out the image from,
 475  * distort_matrix is a precalculated array of how to distort the matrix
 476  */
 477
 478 static void fast_draw_8(XImage *src, XImage *dest, int x, int y, int *distort_matrix) {
 479         CARD8 *u = (CARD8 *)dest->data;
 480         CARD8 *t = (CARD8 *)src->data + x + y*src->bytes_per_line/sizeof(CARD8);
 481
 482         while (u < (CARD8 *)(dest->data + sizeof(CARD8)*dest->height
 483                                 *dest->bytes_per_line/sizeof(CARD8))) {
 484                 *u++ = t[*distort_matrix++];
 485         }
 486 }
 487
 488 static void fast_draw_16(XImage *src, XImage *dest, int x, int y, int *distort_matrix) {
 489         CARD16 *u = (CARD16 *)dest->data;
 490         CARD16 *t = (CARD16 *)src->data + x + y*src->bytes_per_line/sizeof(CARD16);
 491
 492         while (u < (CARD16 *)(dest->data + sizeof(CARD16)*dest->height
 493                                 *dest->bytes_per_line/sizeof(CARD16))) {
 494                 *u++ = t[*distort_matrix++];
 495         }
 496 }
 497
 498 static void fast_draw_32(XImage *src, XImage *dest, int x, int y, int *distort_matrix) {
 499         CARD32 *u = (CARD32 *)dest->data;
 500         CARD32 *t = (CARD32 *)src->data + x + y*src->bytes_per_line/sizeof(CARD32);
 501
 502         while (u < (CARD32 *)(dest->data + sizeof(CARD32)*dest->height
 503                                 *dest->bytes_per_line/sizeof(CARD32))) {
 504                 *u++ = t[*distort_matrix++];
 505         }
 506 }
 507
 508 static void generic_draw(XImage *src, XImage *dest, int x, int y, int *distort_matrix) {
 509         int i, j;
 510         for (i = 0; i < dest->width; i++)
 511                 for (j = 0; j < dest->height; j++)
 512                         if (from[i][j][0] + x >= 0 &&
 513                                         from[i][j][0] + x < src->width &&
 514                                         from[i][j][1] + y >= 0 &&
 515                                         from[i][j][1] + y < src->height)
 516                                 XPutPixel(dest, i, j,
 517                                                 XGetPixel(src,
 518                                                         from[i][j][0] + x,
 519                                                         from[i][j][1] + y));
 520 }
 521
 522 /* generate an XImage of from[][][] and draw it on the screen */
 523 static void plain_draw(int k)
 524 {
 525         if (xy_coo[k].x+2*radius+speed+2 > orig_map->width ||
 526                         xy_coo[k].y+2*radius+speed+2 > orig_map->height)
 527                 return;
 528
 529         draw_routine(orig_map, buffer_map, xy_coo[k].x, xy_coo[k].y, fast_from);
 530
 531 # ifdef HAVE_XSHM_EXTENSION
 532         if (use_shm)
 533                 XShmPutImage(g_dpy, g_window, gc, buffer_map, 0, 0, xy_coo[k].x, xy_coo[k].y,
 534                                 2*radius+speed+2, 2*radius+speed+2, False);
 535         else
 536
 537         if (!use_shm)
 538 # endif
 539                 XPutImage(g_dpy, g_window, gc, buffer_map, 0, 0, xy_coo[k].x, xy_coo[k].y,
 540                                 2*radius+speed+2, 2*radius+speed+2);
 541
 542 }
 543
 544
 545 /* generate an XImage from the reflect algoritm submitted by
 546  * Randy Zack <randy@acucorp.com>
 547  * draw really got too big and ugly so I split it up
 548  * it should be possible to use the from[][] to speed it up
 549  * (once I figure out the algorithm used :)
 550  */
 551 static void reflect_draw(int k)
 552 {
 553         int i, j;
 554         int     cx, cy;
 555         int     ly, lysq, lx, ny, dist, rsq = radius * radius;
 556
 557         cx = cy = radius;
 558         if (xy_coo[k].ymove > 0)
 559                 cy += speed;
 560         if (xy_coo[k].xmove > 0)
 561                 cx += speed;
 562
 563         for(i = 0 ; i < 2*radius+speed+2; i++) {
 564                 ly = i - cy;
 565                 lysq = ly * ly;
 566                 ny = xy_coo[k].y + i;
 567                 for(j = 0 ; j < 2*radius+speed+2 ; j++) {
 568                         lx = j - cx;
 569                         dist = lx * lx + lysq;
 570                         if (dist > rsq ||
 571                                 ly < -radius || ly > radius ||
 572                                 lx < -radius || lx > radius)
 573                                 XPutPixel( buffer_map, j, i,
 574                                                    XGetPixel( orig_map, xy_coo[k].x + j, ny ));
 575                         else if (dist == 0)
 576                                 XPutPixel( buffer_map, j, i, black_pixel );
 577                         else {
 578                                 int     x = xy_coo[k].x + cx + (lx * rsq / dist);
 579                                 int     y = xy_coo[k].y + cy + (ly * rsq / dist);
 580                                 if (x < 0 || x >= xgwa.width ||
 581                                         y < 0 || y >= xgwa.height)
 582                                         XPutPixel( buffer_map, j, i, black_pixel );
 583                                 else
 584                                         XPutPixel( buffer_map, j, i,
 585                                                            XGetPixel( orig_map, x, y ));
 586                         }
 587                 }
 588         }
 589
 590         XPutImage(g_dpy, g_window, gc, buffer_map, 0, 0, xy_coo[k].x, xy_coo[k].y,
 591                         2*radius+speed+2, 2*radius+speed+2);
 592 }
 593
 594 /* create a new, random coordinate, that won't interfer with any other
 595  * coordinates, as the drawing routines would be significantly slowed
 596  * down if they were to handle serveral layers of distortions
 597  */
 598 static void new_rnd_coo(int k)
 599 {
 600         int i;
 601
 602         xy_coo[k].x = (random() % (xgwa.width-2*radius));
 603         xy_coo[k].y = (random() % (xgwa.height-2*radius));
 604
 605         for (i = 0; i < number; i++) {
 606                 if (i != k) {
 607                         if ((abs(xy_coo[k].x - xy_coo[i].x) <= 2*radius+speed+2)
 608                          && (abs(xy_coo[k].y - xy_coo[i].y) <= 2*radius+speed+2)) {
 609                                 xy_coo[k].x = (random() % (xgwa.width-2*radius));
 610                                 xy_coo[k].y = (random() % (xgwa.height-2*radius));
 611                                 i=-1; /* ugly */
 612                         }
 613                 }
 614         }
 615 }
 616
 617 /* move lens and handle bounces with walls and other lenses */
 618 static void move_lense(int k)
 619 {
 620         int i;
 621
 622         if (xy_coo[k].x + 2*radius + speed + 2 >= xgwa.width)
 623                 xy_coo[k].xmove = -abs(xy_coo[k].xmove);
 624         if (xy_coo[k].x <= speed)
 625                 xy_coo[k].xmove = abs(xy_coo[k].xmove);
 626         if (xy_coo[k].y + 2*radius + speed + 2 >= xgwa.height)
 627                 xy_coo[k].ymove = -abs(xy_coo[k].ymove);
 628         if (xy_coo[k].y <= speed)
 629                 xy_coo[k].ymove = abs(xy_coo[k].ymove);
 630
 631         xy_coo[k].x = xy_coo[k].x + xy_coo[k].xmove;
 632         xy_coo[k].y = xy_coo[k].y + xy_coo[k].ymove;
 633
 634         /* bounce against othe lenses */
 635         for (i = 0; i < number; i++) {
 636                 if ((i != k)
 637
 638 /* This commented test is for rectangular lenses (not currently used) and
 639  * the one used is for circular ones
 640                 && (abs(xy_coo[k].x - xy_coo[i].x) <= 2*radius)
 641                 && (abs(xy_coo[k].y - xy_coo[i].y) <= 2*radius)) { */
 642
 643                 && ((xy_coo[k].x - xy_coo[i].x)*(xy_coo[k].x - xy_coo[i].x)
 644                   + (xy_coo[k].y - xy_coo[i].y)*(xy_coo[k].y - xy_coo[i].y)
 645                         <= 2*radius*2*radius)) {
 646
 647                         int x, y;
 648                         x = xy_coo[k].xmove;
 649                         y = xy_coo[k].ymove;
 650                         xy_coo[k].xmove = xy_coo[i].xmove;
 651                         xy_coo[k].ymove = xy_coo[i].ymove;
 652                         xy_coo[i].xmove = x;
 653                         xy_coo[i].ymove = y;
 654                 }
 655         }
 656
 657 }
 658
 659 /* make xy_coo[k] grow/shrink */
 660 static void swamp_thing(int k)
 661 {
 662         if (xy_coo[k].r >= radius)
 663                 xy_coo[k].r_change = -abs(xy_coo[k].r_change);
 664
 665         if (xy_coo[k].r <= 0) {
 666                 from = from_array[0];
 667                 draw(k);
 668                 xy_coo[k].r_change = abs(xy_coo[k].r_change);
 669                 new_rnd_coo(k);
 670                 xy_coo[k].r=xy_coo[k].r_change;
 671                 return;
 672         }
 673
 674         xy_coo[k].r = xy_coo[k].r + xy_coo[k].r_change;
 675
 676         if (xy_coo[k].r >= radius)
 677                 xy_coo[k].r = radius;
 678         if (xy_coo[k].r <= 0)
 679                 xy_coo[k].r=0;
 680
 681         from = from_array[xy_coo[k].r];
 682 }
 683
 684
 685 \f
 686
 687 char *progclass = "Distort";
 688
 689 char *defaults [] = {
 690         "*dontClearRoot:                True",
 691 #ifdef __sgi    /* really, HAVE_READ_DISPLAY_EXTENSION */
 692         "*visualID:                     Best",
 693 #endif
 694
 695         "*delay:                        1000",
 696         "*radius:                       0",
 697         "*speed:                        0",
 698         "*number:                       0",
 699         "*vortex:                       False",
 700         "*magnify:                      False",
 701         "*swamp:                        False",
 702         "*bounce:                       False",
 703         "*reflect:                      False",
 704         "*blackhole:            False",
 705 #ifdef HAVE_XSHM_EXTENSION
 706         "*useSHM:                       False",         /* xshm turns out not to help. */
 707 #endif /* HAVE_XSHM_EXTENSION */
 708         0
 709 };
 710
 711 XrmOptionDescRec options [] = {
 712         { "-delay",     ".delay",       XrmoptionSepArg, 0 },
 713         { "-radius",    ".radius",      XrmoptionSepArg, 0 },
 714         { "-speed",     ".speed",       XrmoptionSepArg, 0 },
 715         { "-number",    ".number",      XrmoptionSepArg, 0 },
 716         { "-swamp",     ".swamp",       XrmoptionNoArg, "True" },
 717         { "-bounce",    ".bounce",      XrmoptionNoArg, "True" },
 718         { "-reflect",   ".reflect",     XrmoptionNoArg, "True" },
 719         { "-vortex",    ".vortex",      XrmoptionNoArg, "True" },
 720         { "-magnify",   ".magnify",     XrmoptionNoArg, "True" },
 721         { "-blackhole", ".blackhole",   XrmoptionNoArg, "True" },
 722         { "-slow",      ".slow",        XrmoptionNoArg, "True" },
 723 #ifdef HAVE_XSHM_EXTENSION
 724         { "-shm",               ".useSHM",      XrmoptionNoArg, "True" },
 725         { "-no-shm",    ".useSHM",      XrmoptionNoArg, "False" },
 726 #endif /* HAVE_XSHM_EXTENSION */
 727         { 0, 0, 0, 0 }
 728 };
 729
 730
 731 void screenhack(Display *dpy, Window window)
 732 {
 733         int k;
 734
 735         init_distort (dpy, window);
 736         while (1) {
 737                 for (k = 0; k < number; k++) {
 738                         effect(k);
 739                         draw(k);
 740                 }
 741
 742                 XSync(dpy, False);
 743         screenhack_handle_events (dpy);
 744                 if (delay) usleep(delay);
 745         }
 746
 747 }