1 /* interference.c --- colored fields via decaying sinusoidal waves.
2 * An entry for the RHAD Labs Screensaver Contest.
4 * Author: Hannu Mallat <hmallat@cs.hut.fi>
6 * Copyright (C) 1998 Hannu Mallat.
8 * Permission to use, copy, modify, distribute, and sell this software and its
9 * documentation for any purpose is hereby granted without fee, provided that
10 * the above copyright notice appear in all copies and that both that
11 * copyright notice and this permission notice appear in supporting
12 * documentation. No representations are made about the suitability of this
13 * software for any purpose. It is provided "as is" without express or
16 * decaying sinusoidal waves, which extend spherically from their
17 * respective origins, move around the plane. a sort of interference
18 * between them is calculated and the resulting twodimensional wave
19 * height map is plotted in a grid, using softly changing colours.
21 * not physically (or in any sense) accurate, but fun to look at for
22 * a while. you may tune the speed/resolution/interestingness tradeoff
23 * with X resources, see below.
25 * Created : Wed Apr 22 09:30:30 1998, hmallat
26 * Last modified: Wed Apr 22 09:30:30 1998, hmallat
27 * Last modified: Sun Aug 31 23:40:14 2003,
28 * david slimp <rock808@DavidSlimp.com>
29 * added -hue option to specify base color hue
33 * This really needs to be sped up.
35 * I've tried making it use XPutPixel/XPutImage instead of XFillRectangle,
36 * but that doesn't seem to help (it's the same speed at gridsize=1, and
37 * it actually makes it slower at larger sizes.)
39 * I played around with shared memory, but clearly I still don't know how
40 * to use the XSHM extension properly, because it doesn't work yet.
42 * Hannu had put in code to use the double-buffering extension, but that
43 * code didn't work for me on Irix. I don't think it would help anyway,
44 * since it's not the swapping of frames that is the bottleneck (or a source
45 * of visible flicker.)
52 #include "screenhack.h"
54 # include <X11/Xutil.h>
56 /* I thought it would be faster this way, but it turns out not to be... -jwz */
60 # undef HAVE_XSHM_EXTENSION /* only applicable when using XImages */
61 #endif /* USE_XIMAGE */
64 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
66 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
68 #ifdef HAVE_XSHM_EXTENSION
70 #endif /* HAVE_XSHM_EXTENSION */
72 char *progclass="Interference";
77 "*count: 3", /* number of waves */
78 "*gridsize: 4", /* pixel size, smaller values for better resolution */
79 "*ncolors: 128", /* number of colours used */
80 "*hue: 0", /* hue to use for base color (0-360) */
81 "*speed: 30", /* speed of wave origins moving around */
82 "*delay: 30000", /* or something */
83 "*color-shift: 60", /* h in hsv space, smaller values for smaller
85 "*radius: 800", /* wave extent */
86 "*gray: false", /* color or grayscale */
87 "*mono: false", /* monochrome, not very much fun */
89 "*doubleBuffer: True",
90 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
91 "*useDBE: True", /* use double buffering extension */
92 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
94 #ifdef HAVE_XSHM_EXTENSION
95 "*useSHM: True", /* use shared memory extension */
96 #endif /* HAVE_XSHM_EXTENSION */
100 XrmOptionDescRec options [] = {
101 { "-count", ".count", XrmoptionSepArg, 0 },
102 { "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
103 { "-gridsize", ".gridsize", XrmoptionSepArg, 0 },
104 { "-hue", ".hue", XrmoptionSepArg, 0 },
105 { "-speed", ".speed", XrmoptionSepArg, 0 },
106 { "-delay", ".delay", XrmoptionSepArg, 0 },
107 { "-color-shift", ".color-shift", XrmoptionSepArg, 0 },
108 { "-radius", ".radius", XrmoptionSepArg, 0 },
109 { "-gray", ".gray", XrmoptionNoArg, "True" },
110 { "-mono", ".mono", XrmoptionNoArg, "True" },
111 { "-db", ".doubleBuffer", XrmoptionNoArg, "True" },
112 { "-no-db", ".doubleBuffer", XrmoptionNoArg, "False" },
113 #ifdef HAVE_XSHM_EXTENSION
114 { "-shm", ".useSHM", XrmoptionNoArg, "True" },
115 { "-no-shm", ".useSHM", XrmoptionNoArg, "False" },
116 #endif /* HAVE_XSHM_EXTENSION */
120 int options_size = (sizeof (options) / sizeof (XrmOptionDescRec));
122 struct inter_source {
129 struct inter_context {
131 * Display-related entries
136 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
137 XdbeBackBuffer back_buf;
138 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
144 #endif /* USE_XIMAGE */
146 #ifdef HAVE_XSHM_EXTENSION
148 XShmSegmentInfo shm_info;
149 #endif /* HAVE_XSHM_EXTENSION */
164 * Drawing-related entries
178 * Interference sources
180 struct inter_source* source;
183 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
184 # define TARGET(c) ((c)->back_buf ? (c)->back_buf : \
185 (c)->pix_buf ? (c)->pix_buf : (c)->win)
186 #else /* HAVE_DOUBLE_BUFFER_EXTENSION */
187 # define TARGET(c) ((c)->pix_buf ? (c)->pix_buf : (c)->win)
188 #endif /* !HAVE_DOUBLE_BUFFER_EXTENSION */
190 void inter_init(Display* dpy, Window win, struct inter_context* c)
192 XWindowAttributes xgwa;
193 double H[3], S[3], V[3];
198 unsigned long valmask = 0;
199 Bool dbuf = get_boolean_resource ("doubleBuffer", "Boolean");
201 memset (c, 0, sizeof(*c));
206 XGetWindowAttributes(c->dpy, c->win, &xgwa);
209 c->cmap = xgwa.colormap;
211 #ifdef HAVE_XSHM_EXTENSION
212 c->use_shm = get_boolean_resource("useSHM", "Boolean");
213 #endif /* HAVE_XSHM_EXTENSION */
217 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
218 c->back_buf = xdbe_get_backbuffer (c->dpy, c->win, XdbeUndefined);
219 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
221 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
223 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
224 c->pix_buf = XCreatePixmap (dpy, win, xgwa.width, xgwa.height,
228 val.function = GXcopy;
229 c->copy_gc = XCreateGC(c->dpy, TARGET(c), GCFunction, &val);
231 c->count = get_integer_resource("count", "Integer");
234 c->grid_size = get_integer_resource("gridsize", "Integer");
237 mono = get_boolean_resource("mono", "Boolean");
239 c->colors = get_integer_resource("ncolors", "Integer");
243 c->hue = get_integer_resource("hue", "Float");
244 while (c->hue < 0 || c->hue >= 360)
245 c->hue = frand(360.0);
246 c->speed = get_integer_resource("speed", "Integer");
247 c->shift = get_float_resource("color-shift", "Float");
248 while(c->shift >= 360.0)
250 while(c->shift <= -360.0)
252 c->radius = get_integer_resource("radius", "Integer");;
260 # ifdef HAVE_XSHM_EXTENSION
263 c->ximage = create_xshm_image(dpy, xgwa.visual, xgwa.depth,
264 ZPixmap, 0, &c->shm_info,
265 xgwa.width, c->grid_size);
269 # endif /* HAVE_XSHM_EXTENSION */
274 XCreateImage (dpy, xgwa.visual,
275 xgwa.depth, ZPixmap, 0, 0, /* depth, fmt, offset, data */
276 xgwa.width, c->grid_size, /* width, height */
277 8, 0); /* pad, bpl */
278 c->ximage->data = (unsigned char *)
279 calloc(c->ximage->height, c->ximage->bytes_per_line);
281 #endif /* USE_XIMAGE */
284 c->pal = calloc(c->colors, sizeof(XColor));
286 gray = get_boolean_resource("gray", "Boolean");
289 H[1] = H[0] + c->shift < 360.0 ? H[0]+c->shift : H[0] + c->shift-360.0;
290 H[2] = H[1] + c->shift < 360.0 ? H[1]+c->shift : H[1] + c->shift-360.0;
291 S[0] = S[1] = S[2] = 1.0;
292 V[0] = V[1] = V[2] = 1.0;
294 H[0] = H[1] = H[2] = 0.0;
295 S[0] = S[1] = S[2] = 0.0;
296 V[0] = 1.0; V[1] = 0.5; V[2] = 0.0;
299 make_color_loop(c->dpy, c->cmap,
303 c->pal, &(c->colors),
305 if(c->colors < 2) { /* color allocation failure */
311 if(mono) { /* DON'T else this with the previous if! */
313 c->pal = calloc(2, sizeof(XColor));
314 c->pal[0].pixel = BlackPixel(c->dpy, DefaultScreen(c->dpy));
315 c->pal[1].pixel = WhitePixel(c->dpy, DefaultScreen(c->dpy));
318 valmask = GCForeground;
319 c->gcs = calloc(c->colors, sizeof(GC));
320 for(i = 0; i < c->colors; i++) {
321 val.foreground = c->pal[i].pixel;
322 c->gcs[i] = XCreateGC(c->dpy, TARGET(c), valmask, &val);
325 c->wave_height = calloc(c->radius, sizeof(int));
326 for(i = 0; i < c->radius; i++) {
329 ((float)c->radius - (float)i) /
333 ((max + max*cos((double)i/50.0)) / 2.0);
336 c->source = calloc(c->count, sizeof(struct inter_source));
337 for(i = 0; i < c->count; i++) {
338 c->source[i].x_theta = frand(2.0)*3.14159;
339 c->source[i].y_theta = frand(2.0)*3.14159;
344 #define source_x(c, i) \
345 (c->w/2 + ((int)(cos(c->source[i].x_theta)*((float)c->w/2.0))))
346 #define source_y(c, i) \
347 (c->h/2 + ((int)(cos(c->source[i].y_theta)*((float)c->h/2.0))))
350 * this is rather suboptimal. the sqrt() doesn't seem to be a big
351 * performance hit, but all those separate XFillRectangle()'s are.
352 * hell, it's just a quick hack anyway -- if someone wishes to tune
356 void do_inter(struct inter_context* c)
365 for(i = 0; i < c->count; i++) {
366 c->source[i].x_theta += (c->speed/1000.0);
367 if(c->source[i].x_theta > 2.0*3.14159)
368 c->source[i].x_theta -= 2.0*3.14159;
369 c->source[i].y_theta += (c->speed/1000.0);
370 if(c->source[i].y_theta > 2.0*3.14159)
371 c->source[i].y_theta -= 2.0*3.14159;
372 c->source[i].x = source_x(c, i);
373 c->source[i].y = source_y(c, i);
378 for(j = 0; j < c->h/g; j++) {
379 for(i = 0; i < c->w/g; i++) {
381 for(k = 0; k < c->count; k++) {
382 dx = i*g + g/2 - c->source[k].x;
383 dy = j*g + g/2 - c->source[k].y;
384 dist = sqrt(dx*dx + dy*dy); /* what's the performance penalty here? */
385 result += (dist > c->radius ? 0 : c->wave_height[dist]);
390 /* Fill in these `gridsize' horizontal bits in the scanline */
391 for(k = 0; k < g; k++)
392 XPutPixel(c->ximage, (g*i)+k, 0, c->pal[result].pixel);
394 #else /* !USE_XIMAGE */
395 XFillRectangle(c->dpy, TARGET(c), c->gcs[result], g*i, g*j, g, g);
396 #endif /* !USE_XIMAGE */
401 /* Only the first scanline of the image has been filled in; clone that
402 scanline to the rest of the `gridsize' lines in the ximage */
403 for(k = 0; k < (g-1); k++)
404 memcpy(c->ximage->data + (c->ximage->bytes_per_line * (k + 1)),
405 c->ximage->data + (c->ximage->bytes_per_line * k),
406 c->ximage->bytes_per_line);
408 /* Move the bits for this horizontal stripe to the server. */
409 # ifdef HAVE_XSHM_EXTENSION
411 XShmPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
412 0, 0, 0, g*j, c->ximage->width, c->ximage->height,
415 # endif /* HAVE_XSHM_EXTENSION */
416 XPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
417 0, 0, 0, g*j, c->ximage->width, c->ximage->height);
419 #endif /* USE_XIMAGE */
422 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
425 XdbeSwapInfo info[1];
426 info[0].swap_window = c->win;
427 info[0].swap_action = XdbeUndefined;
428 XdbeSwapBuffers(c->dpy, info, 1);
431 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
434 XCopyArea (c->dpy, c->pix_buf, c->win, c->copy_gc,
435 0, 0, c->w, c->h, 0, 0);
438 XSync(c->dpy, False);
441 void screenhack(Display *dpy, Window win)
443 struct inter_context c;
446 delay = get_integer_resource("delay", "Integer");
448 inter_init(dpy, win, &c);
451 screenhack_handle_events (dpy);
452 if(delay) usleep(delay);