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
30 * This really needs to be sped up.
32 * I've tried making it use XPutPixel/XPutImage instead of XFillRectangle,
33 * but that doesn't seem to help (it's the same speed at gridsize=1, and
34 * it actually makes it slower at larger sizes.)
36 * I played around with shared memory, but clearly I still don't know how
37 * to use the XSHM extension properly, because it doesn't work yet.
39 * Hannu had put in code to use the double-buffering extension, but that
40 * code didn't work for me on Irix. I don't think it would help anyway,
41 * since it's not the swapping of frames that is the bottleneck (or a source
42 * of visible flicker.)
49 #include "screenhack.h"
51 # include <X11/Xutil.h>
53 /* I thought it would be faster this way, but it turns out not to be... -jwz */
55 #undef HAVE_XSHM_EXTENSION
60 # include <X11/extensions/Xdbe.h>
61 #endif /* HAVE_XDBE */
63 #ifdef HAVE_XSHM_EXTENSION
65 #endif /* HAVE_XSHM_EXTENSION */
67 char *progclass="Interference";
70 "*count: 3", /* number of waves */
71 "*gridsize: 4", /* pixel size, smaller values for better resolution */
72 "*ncolors: 128", /* number of colours used */
73 "*speed: 30", /* speed of wave origins moving around */
74 "*delay: 30000", /* or something */
75 "*color-shift: 60", /* h in hsv space, smaller values for smaller
77 "*radius: 800", /* wave extent */
78 "*gray: false", /* color or grayscale */
79 "*mono: false", /* monochrome, not very much fun */
82 "*useDBE: True", /* use double buffering extension */
83 #endif /* HAVE_XDBE */
85 #ifdef HAVE_XSHM_EXTENSION
86 "*useSHM: True", /* use shared memory extension */
87 #endif /* HAVE_XSHM_EXTENSION */
91 XrmOptionDescRec options [] = {
92 { "-count", ".count", XrmoptionSepArg, 0 },
93 { "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
94 { "-gridsize", ".gridsize", XrmoptionSepArg, 0 },
95 { "-speed", ".speed", XrmoptionSepArg, 0 },
96 { "-delay", ".delay", XrmoptionSepArg, 0 },
97 { "-color-shift", ".color-shift", XrmoptionSepArg, 0 },
98 { "-radius", ".radius", XrmoptionSepArg, 0 },
99 { "-gray", ".gray", XrmoptionNoArg, "True" },
100 { "-mono", ".mono", XrmoptionNoArg, "True" },
102 { "-db", ".useDBE", XrmoptionNoArg, "True" },
103 { "-no-db", ".useDBE", XrmoptionNoArg, "False" },
104 #endif /* HAVE_XDBE */
105 #ifdef HAVE_XSHM_EXTENSION
106 { "-shm", ".useSHM", XrmoptionNoArg, "True" },
107 { "-no-shm", ".useSHM", XrmoptionNoArg, "False" },
108 #endif /* HAVE_XSHM_EXTENSION */
112 int options_size = (sizeof (options) / sizeof (XrmOptionDescRec));
114 struct inter_source {
121 struct inter_context {
123 * Display-related entries
132 #endif /* USE_XIMAGE */
136 #endif /* HAVE_XDBE */
138 #ifdef HAVE_XSHM_EXTENSION
140 XShmSegmentInfo shm_info;
141 #endif /* HAVE_XSHM_EXTENSION */
155 * Drawing-related entries
163 #endif /* HAVE_XDBE */
172 * Interference sources
174 struct inter_source* source;
178 # define TARGET(c) ((c)->has_dbe ? (c)->buf : (c)->dbuf)
179 #else /* HAVE_XDBE */
180 # define TARGET(c) ((c)->dbuf)
181 #endif /* !HAVE_XDBE */
183 void inter_init(Display* dpy, Window win, struct inter_context* c)
185 XWindowAttributes xgwa;
186 double H[3], S[3], V[3];
193 #endif /* HAVE_XDBE */
196 unsigned long valmask = 0;
201 XGetWindowAttributes(c->dpy, c->win, &xgwa);
204 c->cmap = xgwa.colormap;
207 use_dbe = get_boolean_resource("useDBE", "Boolean");
211 c->has_dbe = XdbeQueryExtension(dpy, &major, &minor);
213 #endif /* HAVE_XDBE */
215 #ifdef HAVE_XSHM_EXTENSION
216 c->use_shm = get_boolean_resource("useSHM", "Boolean");
217 #endif /* HAVE_XSHM_EXTENSION */
221 #endif /* HAVE_XDBE */
223 c->dbuf = XCreatePixmap(dpy, win, xgwa.width, xgwa.height, xgwa.depth);
224 val.function = GXcopy;
227 c->copy_gc = XCreateGC(c->dpy, c->dbuf, GCFunction, &val);
229 c->count = get_integer_resource("count", "Integer");
232 c->grid_size = get_integer_resource("gridsize", "Integer");
235 mono = get_boolean_resource("mono", "Boolean");
237 c->colors = get_integer_resource("ncolors", "Integer");
241 c->speed = get_integer_resource("speed", "Integer");
242 c->shift = get_float_resource("color-shift", "Float");
243 while(c->shift >= 360.0)
245 while(c->shift <= -360.0)
247 c->radius = get_integer_resource("radius", "Integer");;
255 # ifdef HAVE_XSHM_EXTENSION
258 c->ximage = create_xshm_image(dpy, xgwa.visual, xgwa.depth,
259 ZPixmap, 0, &c->shm_info,
260 xgwa.width, c->grid_size);
264 # endif /* HAVE_XSHM_EXTENSION */
269 XCreateImage (dpy, xgwa.visual,
270 xgwa.depth, ZPixmap, 0, 0, /* depth, fmt, offset, data */
271 xgwa.width, c->grid_size, /* width, height */
272 8, 0); /* pad, bpl */
273 c->ximage->data = (unsigned char *)
274 calloc(c->ximage->height, c->ximage->bytes_per_line);
276 #endif /* USE_XIMAGE */
279 c->pal = calloc(c->colors, sizeof(XColor));
283 gray = get_boolean_resource("gray", "Boolean");
285 H[0] = drand48()*360.0;
286 H[1] = H[0] + c->shift < 360.0 ? H[0]+c->shift : H[0] + c->shift-360.0;
287 H[2] = H[1] + c->shift < 360.0 ? H[1]+c->shift : H[1] + c->shift-360.0;
288 S[0] = S[1] = S[2] = 1.0;
289 V[0] = V[1] = V[2] = 1.0;
291 H[0] = H[1] = H[2] = 0.0;
292 S[0] = S[1] = S[2] = 0.0;
293 V[0] = 1.0; V[1] = 0.5; V[2] = 0.0;
296 make_color_loop(c->dpy, c->cmap,
300 c->pal, &(c->colors),
302 if(c->colors < 2) { /* color allocation failure */
308 if(mono) { /* DON'T else this with the previous if! */
310 c->pal = calloc(2, sizeof(XColor));
311 c->pal[0].pixel = BlackPixel(c->dpy, DefaultScreen(c->dpy));
312 c->pal[1].pixel = WhitePixel(c->dpy, DefaultScreen(c->dpy));
317 c->buf = XdbeAllocateBackBufferName(c->dpy, c->win, XdbeUndefined);
318 #endif /* HAVE_XDBE */
320 valmask = GCForeground;
321 c->gcs = calloc(c->colors, sizeof(GC));
322 for(i = 0; i < c->colors; i++) {
323 val.foreground = c->pal[i].pixel;
324 c->gcs[i] = XCreateGC(c->dpy, TARGET(c), valmask, &val);
327 c->wave_height = calloc(c->radius, sizeof(int));
328 for(i = 0; i < c->radius; i++) {
331 ((float)c->radius - (float)i) /
335 ((max + max*cos((double)i/50.0)) / 2.0);
338 c->source = calloc(c->count, sizeof(struct inter_source));
339 for(i = 0; i < c->count; i++) {
340 c->source[i].x_theta = drand48()*2.0*3.14159;
341 c->source[i].y_theta = drand48()*2.0*3.14159;
346 #define source_x(c, i) \
347 (c->w/2 + ((int)(cos(c->source[i].x_theta)*((float)c->w/2.0))))
348 #define source_y(c, i) \
349 (c->h/2 + ((int)(cos(c->source[i].y_theta)*((float)c->h/2.0))))
352 * this is rather suboptimal. the sqrt() doesn't seem to be a big
353 * performance hit, but all those separate XFillRectangle()'s are.
354 * hell, it's just a quick hack anyway -- if someone wishes to tune
358 void do_inter(struct inter_context* c)
364 XdbeSwapInfo info[1];
365 #endif /* HAVE_XDBE */
370 for(i = 0; i < c->count; i++) {
371 c->source[i].x_theta += (c->speed/1000.0);
372 if(c->source[i].x_theta > 2.0*3.14159)
373 c->source[i].x_theta -= 2.0*3.14159;
374 c->source[i].y_theta += (c->speed/1000.0);
375 if(c->source[i].y_theta > 2.0*3.14159)
376 c->source[i].y_theta -= 2.0*3.14159;
377 c->source[i].x = source_x(c, i);
378 c->source[i].y = source_y(c, i);
383 for(j = 0; j < c->h/g; j++) {
384 for(i = 0; i < c->w/g; i++) {
386 for(k = 0; k < c->count; k++) {
387 dx = i*g + g/2 - c->source[k].x;
388 dy = j*g + g/2 - c->source[k].y;
389 dist = sqrt(dx*dx + dy*dy); /* what's the performance penalty here? */
390 result += (dist > c->radius ? 0 : c->wave_height[dist]);
395 /* Fill in these `gridsize' horizontal bits in the scanline */
396 for(k = 0; k < g; k++)
397 XPutPixel(c->ximage, (g*i)+k, 0, c->pal[result].pixel);
399 #else /* !USE_XIMAGE */
400 XFillRectangle(c->dpy, TARGET(c), c->gcs[result], g*i, g*j, g, g);
401 #endif /* !USE_XIMAGE */
406 /* Only the first scanline of the image has been filled in; clone that
407 scanline to the rest of the `gridsize' lines in the ximage */
408 for(k = 0; k < (g-1); k++)
409 memcpy(c->ximage->data + (c->ximage->bytes_per_line * (k + 1)),
410 c->ximage->data + (c->ximage->bytes_per_line * k),
411 c->ximage->bytes_per_line);
413 /* Move the bits for this horizontal stripe to the server. */
414 # ifdef HAVE_XSHM_EXTENSION
416 XShmPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
417 0, 0, 0, g*j, c->ximage->width, c->ximage->height,
420 # endif /* HAVE_XSHM_EXTENSION */
421 XPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
422 0, 0, 0, g*j, c->ximage->width, c->ximage->height);
424 #endif /* USE_XIMAGE */
430 info[0].swap_window = c->win;
431 info[0].swap_action = XdbeUndefined;
432 XdbeSwapBuffers(c->dpy, info, 1);
435 #endif /* HAVE_XDBE */
437 XCopyArea (c->dpy, c->dbuf, c->win, c->copy_gc,
438 0, 0, c->w, c->h, 0, 0);
440 XSync(c->dpy, False);
443 void screenhack(Display *dpy, Window win)
445 struct inter_context c;
448 delay = get_integer_resource("delay", "Integer");
450 inter_init(dpy, win, &c);
453 screenhack_handle_events (dpy);
454 if(delay) usleep(delay);