From http://www.jwz.org/xscreensaver/xscreensaver-5.38.tar.gz
[xscreensaver] / hacks / slip.c
1 /* -*- Mode: C; tab-width: 4 -*- */
2 /* slip --- lots of slipping blits */
3
4 #if 0
5 static const char sccsid[] = "@(#)slip.c        5.00 2000/11/01 xlockmore";
6 #endif
7
8 /*-
9  * Copyright (c) 1992 by Scott Draves <spot@cs.cmu.edu>
10  *
11  * Permission to use, copy, modify, and distribute this software and its
12  * documentation for any purpose and without fee is hereby granted,
13  * provided that the above copyright notice appear in all copies and that
14  * both that copyright notice and this permission notice appear in
15  * supporting documentation.
16  *
17  * This file is provided AS IS with no warranties of any kind.  The author
18  * shall have no liability with respect to the infringement of copyrights,
19  * trade secrets or any patents by this file or any part thereof.  In no
20  * event will the author be liable for any lost revenue or profits or
21  * other special, indirect and consequential damages.
22  *
23  * 01-Nov-2000: Allocation checks
24  * 10-May-1997: Jamie Zawinski <jwz@jwz.org> compatible with xscreensaver
25  * 01-Dec-1995: Patched for VMS <joukj@hrem.stm.tudelft.nl>
26  */
27
28 #ifdef STANDALONE
29 # define MODE_slip
30 # define DEFAULTS       "*delay: 50000 \n" \
31                                         "*count: 35 \n" \
32                                         "*cycles: 50 \n" \
33                                         "*ncolors: 200 \n" \
34                                         "*fpsSolid:     true \n" \
35                                         "*ignoreRotation: True \n" \
36
37 # define free_slip 0
38 # define release_slip 0
39 # include "xlockmore.h"         /* in xscreensaver distribution */
40 #else /* STANDALONE */
41 # include "xlock.h"             /* in xlockmore distribution */
42 #endif /* STANDALONE */
43
44 #ifdef MODE_slip
45
46 ENTRYPOINT ModeSpecOpt slip_opts =
47 {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
48
49 #ifdef USE_MODULES
50 ModStruct   slip_description =
51 {"slip", "init_slip", "draw_slip", (char *) NULL,
52  "init_slip", "init_slip", (char *) NULL, &slip_opts,
53  50000, 35, 50, 1, 64, 1.0, "",
54  "Shows slipping blits", 0, NULL};
55
56 #endif
57
58 typedef struct {
59         int         width, height;
60         int         nblits_remaining;
61         int         blit_width, blit_height;
62         int         mode;
63         int         first_time;
64         int         backwards;
65         short       lasthalf;
66         int         stage;
67         unsigned long r;
68     Bool image_loading_p;
69 } slipstruct;
70 static slipstruct *slips = (slipstruct *) NULL;
71
72 static short
73 halfrandom(slipstruct *sp, int mv)
74 {
75         unsigned long r;
76
77         if (sp->lasthalf) {
78                 r = sp->lasthalf;
79                 sp->lasthalf = 0;
80         } else {
81                 r = LRAND();
82                 sp->lasthalf = (short) (r >> 16);
83         }
84         return r % mv;
85 }
86
87 static int
88 erandom(slipstruct *sp, int mv)
89 {
90         int         res;
91
92         if (0 == sp->stage) {
93                 sp->r = LRAND();
94                 sp->stage = 7;
95         }
96         res = (int) (sp->r & 0xf);
97         sp->r = sp->r >> 4;
98         sp->stage--;
99         if (res & 8)
100                 return res & mv;
101         else
102                 return -(res & mv);
103 }
104
105 #ifdef STANDALONE
106 static void
107 image_loaded_cb (Screen *screen, Window w, Drawable d,
108                  const char *name, XRectangle *geom,
109                  void *closure)
110 {
111   ModeInfo *mi = (ModeInfo *) closure;
112   slipstruct *sp = &slips[MI_SCREEN(mi)];
113   Display *dpy = DisplayOfScreen (screen);
114   XCopyArea (dpy, d, w, mi->gc, 0, 0,
115              sp->width, sp->height, 0, 0);
116   XFreePixmap (dpy, d);
117   sp->image_loading_p = False;
118 }
119 #endif /* STANDALONE */
120
121 static Bool
122 prepare_screen(ModeInfo * mi, slipstruct * sp)
123 {
124
125         Display    *display = MI_DISPLAY(mi);
126         GC          gc = MI_GC(mi);
127         int         i, n, w = sp->width / 20;
128         int         not_solid = halfrandom(sp, 10);
129
130         sp->backwards = (int) (LRAND() & 1);    /* jwz: go the other way sometimes */
131
132         if (sp->first_time) {
133                 XClearWindow (display, MI_WINDOW(mi));
134                 n = 300;
135         } else if (!sp->image_loading_p && !halfrandom(sp, 10)) {
136                 sp->first_time = 1;
137                 sp->nblits_remaining = 0;
138                 MI_CLEARWINDOW(mi);
139                 return False;
140         } else {
141                 if (halfrandom(sp, 5))
142                         return True;
143                 if (halfrandom(sp, 5))
144                         n = 100;
145                 else
146                         n = 2000;
147         }
148
149         if (MI_NPIXELS(mi) > 2)
150                 XSetForeground(display, gc, MI_PIXEL(mi, halfrandom(sp, MI_NPIXELS(mi))));
151         else if (halfrandom(sp, 2))
152                 XSetForeground(display, gc, MI_WHITE_PIXEL(mi));
153         else
154                 XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
155
156         for (i = 0; i < n; i++) {
157                 int         ww = ((w / 2) + halfrandom(sp, MAX(w, 1)));
158
159                 if (not_solid) {
160                         if (MI_NPIXELS(mi) > 2)
161                                 XSetForeground(display, gc, MI_PIXEL(mi, halfrandom(sp, MI_NPIXELS(mi))));
162                         else if (halfrandom(sp, 2))
163                                 XSetForeground(display, gc, MI_WHITE_PIXEL(mi));
164                         else
165                                 XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
166                 }
167                 XFillRectangle(display, MI_WINDOW(mi), gc,
168                                halfrandom(sp, MAX(sp->width - ww, 1)),
169                                halfrandom(sp, MAX(sp->height - ww, 1)),
170                                ww, ww);
171         }
172         sp->first_time = 0;
173
174
175 #ifdef STANDALONE                         /* jwz -- sometimes hack the desktop image! */
176         if (!sp->image_loading_p &&
177         (1||halfrandom(sp, 2) == 0)) {
178       /* Load it into a pixmap so that the "Loading" message and checkerboard
179          don't show up on the window -- we keep running while the image is
180          in progress... */
181       Pixmap p = XCreatePixmap (MI_DISPLAY(mi), MI_WINDOW(mi),
182                                 sp->width, sp->height, mi->xgwa.depth);
183       sp->image_loading_p = True;
184       load_image_async (ScreenOfDisplay (MI_DISPLAY(mi), 0/*####MI_SCREEN(mi)*/),
185                         MI_WINDOW(mi), p, image_loaded_cb, mi);
186         }
187 #endif
188
189         return True;
190 }
191
192 static int
193 quantize(double d)
194 {
195         int         i = (int) floor(d);
196         double      f = d - i;
197
198         if ((LRAND() & 0xff) < f * 0xff)
199                 i++;
200         return i;
201 }
202
203 ENTRYPOINT void
204 reshape_slip (ModeInfo * mi, int w, int h)
205 {
206   slipstruct *sp = &slips[MI_SCREEN(mi)];
207   sp->width = w;
208   sp->height = h;
209   sp->blit_width = sp->width / 25;
210   sp->blit_height = sp->height / 25;
211
212   sp->mode = 0;
213   sp->nblits_remaining = 0;
214 }
215
216 ENTRYPOINT void
217 init_slip (ModeInfo * mi)
218 {
219         slipstruct *sp;
220
221         MI_INIT (mi, slips);
222         sp = &slips[MI_SCREEN(mi)];
223
224         sp->nblits_remaining = 0;
225         sp->mode = 0;
226         sp->first_time = 1;
227
228         /* no "NoExpose" events from XCopyArea wanted */
229         XSetGraphicsExposures(MI_DISPLAY(mi), MI_GC(mi), False);
230
231     reshape_slip (mi, MI_WIDTH(mi), MI_HEIGHT(mi));
232 }
233
234 ENTRYPOINT void
235 draw_slip (ModeInfo * mi)
236 {
237         Display    *display = MI_DISPLAY(mi);
238         Window      window = MI_WINDOW(mi);
239         GC          gc = MI_GC(mi);
240         int         timer;
241         slipstruct *sp;
242
243         if (slips == NULL)
244                 return;
245         sp = &slips[MI_SCREEN(mi)];
246
247         timer = MI_COUNT(mi) * MI_CYCLES(mi);
248
249         while (timer--) {
250                 int         xi = halfrandom(sp, MAX(sp->width - sp->blit_width, 1));
251                 int         yi = halfrandom(sp, MAX(sp->height - sp->blit_height, 1));
252                 double      x, y, dx = 0, dy = 0, t, s1, s2;
253
254                 if (0 == sp->nblits_remaining--) {
255                         static const int lut[] = {0, 0, 0, 1, 1, 1, 2};
256
257                         if (!prepare_screen(mi, sp))
258                                 break;
259                         MI_IS_DRAWN(mi) = True;
260                         sp->nblits_remaining = MI_COUNT(mi) *
261                                 (2000 + halfrandom(sp, 1000) + halfrandom(sp, 1000));
262                         if (sp->mode == 2)
263                                 sp->mode = halfrandom(sp, 2);
264                         else
265                                 sp->mode = lut[halfrandom(sp, 7)];
266                 }
267                 x = (2 * xi + sp->blit_width) / (double) sp->width - 1;
268                 y = (2 * yi + sp->blit_height) / (double) sp->height - 1;
269
270                 /* (x,y) is in biunit square */
271                 switch (sp->mode) {
272                         case 0: /* rotor */
273                                 dx = x;
274                                 dy = y;
275
276                                 if (dy < 0) {
277                                         dy += 0.04;
278                                         if (dy > 0)
279                                                 dy = 0.00;
280                                 }
281                                 if (dy > 0) {
282                                         dy -= 0.04;
283                                         if (dy < 0)
284                                                 dy = 0.00;
285                                 }
286                                 t = dx * dx + dy * dy + 1e-10;
287                                 s1 = 2 * dx * dx / t - 1;
288                                 s2 = 2 * dx * dy / t;
289                                 dx = s1 * 5;
290                                 dy = s2 * 5;
291
292                                 if (sp->backwards) {    /* jwz: go the other way sometimes */
293                                         dx = -dx;
294                                         dy = -dy;
295                                 }
296                                 break;
297                         case 1: /* shuffle */
298                                 dx = erandom(sp, 3);
299                                 dy = erandom(sp, 3);
300                                 break;
301                         case 2: /* explode */
302                                 dx = x * 3;
303                                 dy = y * 3;
304                                 break;
305                 }
306                 {
307                         int         qx = xi + quantize(dx), qy = yi + quantize(dy);
308                         int         wrap;
309
310                         if (qx < 0 || qy < 0 ||
311                             qx >= sp->width - sp->blit_width ||
312                             qy >= sp->height - sp->blit_height)
313                                 continue;
314
315 /*-
316 Seems to cause problems using Exceed
317 with PseudoColor
318 X Error of failed request:  BadGC (invalid GC parameter)
319 with TrueColor
320 X Error of failed request:  BadDrawable (invalid Pixmap or Window parameter)
321   Major opcode of failed request:  62 (X_CopyArea)
322  */
323                         XCopyArea(display, window, window, gc, xi, yi,
324                                   sp->blit_width, sp->blit_height,
325                                   qx, qy);
326                         switch (sp->mode) {
327                                 case 0:
328                                         /* wrap */
329                                         wrap = sp->width - (2 * sp->blit_width);
330                                         if (qx > wrap ) {
331                                                 XCopyArea(display, window, window, gc, qx, qy,
332                                                 sp->blit_width, sp->blit_height,
333                                                           qx - wrap, qy);
334                                         }
335                                         if (qx < 2 * sp->blit_width) {
336                                                 XCopyArea(display, window, window, gc, qx, qy,
337                                                 sp->blit_width, sp->blit_height,
338                                                           qx + wrap, qy);
339                                         }
340                                         wrap = sp->height - (2 * sp->blit_height);
341                                         if (qy > wrap) {
342                                                 XCopyArea(display, window, window, gc, qx, qy,
343                                                 sp->blit_width, sp->blit_height,
344                                                           qx, qy - wrap);
345                                         }
346                                         if (qy < 2 * sp->blit_height) {
347                                                 XCopyArea(display, window, window, gc, qx, qy,
348                                                 sp->blit_width, sp->blit_height,
349                                                           qx, qy + wrap);
350                                         }
351                                         break;
352                                 case 1:
353                                 case 2:
354                                         break;
355                         }
356                 }
357         }
358 }
359
360 ENTRYPOINT Bool
361 slip_handle_event (ModeInfo *mi, XEvent *event)
362 {
363   slipstruct *sp = &slips[MI_SCREEN(mi)];
364   if (screenhack_event_helper (MI_DISPLAY(mi), MI_WINDOW(mi), event))
365     {
366       sp->first_time = 1;
367       sp->nblits_remaining = 0;
368       return True;
369     }
370   return False;
371 }
372
373 XSCREENSAVER_MODULE ("Slip", slip)
374
375 #endif /* MODE_slip */