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 */
57 # undef HAVE_XSHM_EXTENSION /* only applicable when using XImages */
58 #endif /* USE_XIMAGE */
61 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
63 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
65 #ifdef HAVE_XSHM_EXTENSION
67 #endif /* HAVE_XSHM_EXTENSION */
69 char *progclass="Interference";
72 "*count: 3", /* number of waves */
73 "*gridsize: 4", /* pixel size, smaller values for better resolution */
74 "*ncolors: 128", /* number of colours used */
75 "*speed: 30", /* speed of wave origins moving around */
76 "*delay: 30000", /* or something */
77 "*color-shift: 60", /* h in hsv space, smaller values for smaller
79 "*radius: 800", /* wave extent */
80 "*gray: false", /* color or grayscale */
81 "*mono: false", /* monochrome, not very much fun */
83 "*doubleBuffer: True",
84 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
85 "*useDBE: True", /* use double buffering extension */
86 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
88 #ifdef HAVE_XSHM_EXTENSION
89 "*useSHM: True", /* use shared memory extension */
90 #endif /* HAVE_XSHM_EXTENSION */
94 XrmOptionDescRec options [] = {
95 { "-count", ".count", XrmoptionSepArg, 0 },
96 { "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
97 { "-gridsize", ".gridsize", XrmoptionSepArg, 0 },
98 { "-speed", ".speed", XrmoptionSepArg, 0 },
99 { "-delay", ".delay", XrmoptionSepArg, 0 },
100 { "-color-shift", ".color-shift", XrmoptionSepArg, 0 },
101 { "-radius", ".radius", XrmoptionSepArg, 0 },
102 { "-gray", ".gray", XrmoptionNoArg, "True" },
103 { "-mono", ".mono", XrmoptionNoArg, "True" },
104 { "-db", ".doubleBuffer", XrmoptionNoArg, "True" },
105 { "-no-db", ".doubleBuffer", XrmoptionNoArg, "False" },
106 #ifdef HAVE_XSHM_EXTENSION
107 { "-shm", ".useSHM", XrmoptionNoArg, "True" },
108 { "-no-shm", ".useSHM", XrmoptionNoArg, "False" },
109 #endif /* HAVE_XSHM_EXTENSION */
113 int options_size = (sizeof (options) / sizeof (XrmOptionDescRec));
115 struct inter_source {
122 struct inter_context {
124 * Display-related entries
129 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
130 XdbeBackBuffer back_buf;
131 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
137 #endif /* USE_XIMAGE */
139 #ifdef HAVE_XSHM_EXTENSION
141 XShmSegmentInfo shm_info;
142 #endif /* HAVE_XSHM_EXTENSION */
156 * Drawing-related entries
170 * Interference sources
172 struct inter_source* source;
175 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
176 # define TARGET(c) ((c)->back_buf ? (c)->back_buf : \
177 (c)->pix_buf ? (c)->pix_buf : (c)->win)
178 #else /* HAVE_DOUBLE_BUFFER_EXTENSION */
179 # define TARGET(c) ((c)->pix_buf ? (c)->pix_buf : (c)->win)
180 #endif /* !HAVE_DOUBLE_BUFFER_EXTENSION */
182 void inter_init(Display* dpy, Window win, struct inter_context* c)
184 XWindowAttributes xgwa;
185 double H[3], S[3], V[3];
190 unsigned long valmask = 0;
191 Bool dbuf = get_boolean_resource ("doubleBuffer", "Boolean");
193 memset (c, 0, sizeof(*c));
198 XGetWindowAttributes(c->dpy, c->win, &xgwa);
201 c->cmap = xgwa.colormap;
203 #ifdef HAVE_XSHM_EXTENSION
204 c->use_shm = get_boolean_resource("useSHM", "Boolean");
205 #endif /* HAVE_XSHM_EXTENSION */
209 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
210 c->back_buf = xdbe_get_backbuffer (c->dpy, c->win, XdbeUndefined);
211 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
213 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
215 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
216 c->pix_buf = XCreatePixmap (dpy, win, xgwa.width, xgwa.height,
220 val.function = GXcopy;
221 c->copy_gc = XCreateGC(c->dpy, TARGET(c), GCFunction, &val);
223 c->count = get_integer_resource("count", "Integer");
226 c->grid_size = get_integer_resource("gridsize", "Integer");
229 mono = get_boolean_resource("mono", "Boolean");
231 c->colors = get_integer_resource("ncolors", "Integer");
235 c->speed = get_integer_resource("speed", "Integer");
236 c->shift = get_float_resource("color-shift", "Float");
237 while(c->shift >= 360.0)
239 while(c->shift <= -360.0)
241 c->radius = get_integer_resource("radius", "Integer");;
249 # ifdef HAVE_XSHM_EXTENSION
252 c->ximage = create_xshm_image(dpy, xgwa.visual, xgwa.depth,
253 ZPixmap, 0, &c->shm_info,
254 xgwa.width, c->grid_size);
258 # endif /* HAVE_XSHM_EXTENSION */
263 XCreateImage (dpy, xgwa.visual,
264 xgwa.depth, ZPixmap, 0, 0, /* depth, fmt, offset, data */
265 xgwa.width, c->grid_size, /* width, height */
266 8, 0); /* pad, bpl */
267 c->ximage->data = (unsigned char *)
268 calloc(c->ximage->height, c->ximage->bytes_per_line);
270 #endif /* USE_XIMAGE */
273 c->pal = calloc(c->colors, sizeof(XColor));
277 gray = get_boolean_resource("gray", "Boolean");
280 H[1] = H[0] + c->shift < 360.0 ? H[0]+c->shift : H[0] + c->shift-360.0;
281 H[2] = H[1] + c->shift < 360.0 ? H[1]+c->shift : H[1] + c->shift-360.0;
282 S[0] = S[1] = S[2] = 1.0;
283 V[0] = V[1] = V[2] = 1.0;
285 H[0] = H[1] = H[2] = 0.0;
286 S[0] = S[1] = S[2] = 0.0;
287 V[0] = 1.0; V[1] = 0.5; V[2] = 0.0;
290 make_color_loop(c->dpy, c->cmap,
294 c->pal, &(c->colors),
296 if(c->colors < 2) { /* color allocation failure */
302 if(mono) { /* DON'T else this with the previous if! */
304 c->pal = calloc(2, sizeof(XColor));
305 c->pal[0].pixel = BlackPixel(c->dpy, DefaultScreen(c->dpy));
306 c->pal[1].pixel = WhitePixel(c->dpy, DefaultScreen(c->dpy));
309 valmask = GCForeground;
310 c->gcs = calloc(c->colors, sizeof(GC));
311 for(i = 0; i < c->colors; i++) {
312 val.foreground = c->pal[i].pixel;
313 c->gcs[i] = XCreateGC(c->dpy, TARGET(c), valmask, &val);
316 c->wave_height = calloc(c->radius, sizeof(int));
317 for(i = 0; i < c->radius; i++) {
320 ((float)c->radius - (float)i) /
324 ((max + max*cos((double)i/50.0)) / 2.0);
327 c->source = calloc(c->count, sizeof(struct inter_source));
328 for(i = 0; i < c->count; i++) {
329 c->source[i].x_theta = frand(2.0)*3.14159;
330 c->source[i].y_theta = frand(2.0)*3.14159;
335 #define source_x(c, i) \
336 (c->w/2 + ((int)(cos(c->source[i].x_theta)*((float)c->w/2.0))))
337 #define source_y(c, i) \
338 (c->h/2 + ((int)(cos(c->source[i].y_theta)*((float)c->h/2.0))))
341 * this is rather suboptimal. the sqrt() doesn't seem to be a big
342 * performance hit, but all those separate XFillRectangle()'s are.
343 * hell, it's just a quick hack anyway -- if someone wishes to tune
347 void do_inter(struct inter_context* c)
356 for(i = 0; i < c->count; i++) {
357 c->source[i].x_theta += (c->speed/1000.0);
358 if(c->source[i].x_theta > 2.0*3.14159)
359 c->source[i].x_theta -= 2.0*3.14159;
360 c->source[i].y_theta += (c->speed/1000.0);
361 if(c->source[i].y_theta > 2.0*3.14159)
362 c->source[i].y_theta -= 2.0*3.14159;
363 c->source[i].x = source_x(c, i);
364 c->source[i].y = source_y(c, i);
369 for(j = 0; j < c->h/g; j++) {
370 for(i = 0; i < c->w/g; i++) {
372 for(k = 0; k < c->count; k++) {
373 dx = i*g + g/2 - c->source[k].x;
374 dy = j*g + g/2 - c->source[k].y;
375 dist = sqrt(dx*dx + dy*dy); /* what's the performance penalty here? */
376 result += (dist > c->radius ? 0 : c->wave_height[dist]);
381 /* Fill in these `gridsize' horizontal bits in the scanline */
382 for(k = 0; k < g; k++)
383 XPutPixel(c->ximage, (g*i)+k, 0, c->pal[result].pixel);
385 #else /* !USE_XIMAGE */
386 XFillRectangle(c->dpy, TARGET(c), c->gcs[result], g*i, g*j, g, g);
387 #endif /* !USE_XIMAGE */
392 /* Only the first scanline of the image has been filled in; clone that
393 scanline to the rest of the `gridsize' lines in the ximage */
394 for(k = 0; k < (g-1); k++)
395 memcpy(c->ximage->data + (c->ximage->bytes_per_line * (k + 1)),
396 c->ximage->data + (c->ximage->bytes_per_line * k),
397 c->ximage->bytes_per_line);
399 /* Move the bits for this horizontal stripe to the server. */
400 # ifdef HAVE_XSHM_EXTENSION
402 XShmPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
403 0, 0, 0, g*j, c->ximage->width, c->ximage->height,
406 # endif /* HAVE_XSHM_EXTENSION */
407 XPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
408 0, 0, 0, g*j, c->ximage->width, c->ximage->height);
410 #endif /* USE_XIMAGE */
413 #ifdef HAVE_DOUBLE_BUFFER_EXTENSION
416 XdbeSwapInfo info[1];
417 info[0].swap_window = c->win;
418 info[0].swap_action = XdbeUndefined;
419 XdbeSwapBuffers(c->dpy, info, 1);
422 #endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
425 XCopyArea (c->dpy, c->pix_buf, c->win, c->copy_gc,
426 0, 0, c->w, c->h, 0, 0);
429 XSync(c->dpy, False);
432 void screenhack(Display *dpy, Window win)
434 struct inter_context c;
437 delay = get_integer_resource("delay", "Integer");
439 inter_init(dpy, win, &c);
442 screenhack_handle_events (dpy);
443 if(delay) usleep(delay);