--- /dev/null
+/* interference.c --- colored fields via decaying sinusoidal waves.
+ * An entry for the RHAD Labs Screensaver Contest.
+ *
+ * Author: Hannu Mallat <hmallat@cs.hut.fi>
+ *
+ * Copyright (C) 1998 Hannu Mallat.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that
+ * copyright notice and this permission notice appear in supporting
+ * documentation. No representations are made about the suitability of this
+ * software for any purpose. It is provided "as is" without express or
+ * implied warranty.
+ *
+ * decaying sinusoidal waves, which extend spherically from their
+ * respective origins, move around the plane. a sort of interference
+ * between them is calculated and the resulting twodimensional wave
+ * height map is plotted in a grid, using softly changing colours.
+ *
+ * not physically (or in any sense) accurate, but fun to look at for
+ * a while. you may tune the speed/resolution/interestingness tradeoff
+ * with X resources, see below.
+ *
+ * Created : Wed Apr 22 09:30:30 1998, hmallat
+ * Last modified: Wed Apr 22 09:30:30 1998, hmallat
+ *
+ * TODO:
+ *
+ * This really needs to be sped up.
+ *
+ * I've tried making it use XPutPixel/XPutImage instead of XFillRectangle,
+ * but that doesn't seem to help (it's the same speed at gridsize=1, and
+ * it actually makes it slower at larger sizes.)
+ *
+ * I played around with shared memory, but clearly I still don't know how
+ * to use the XSHM extension properly, because it doesn't work yet.
+ *
+ * Hannu had put in code to use the double-buffering extension, but that
+ * code didn't work for me on Irix. I don't think it would help anyway,
+ * since it's not the swapping of frames that is the bottleneck (or a source
+ * of visible flicker.)
+ *
+ * -- jwz, 4-Jun-98
+ */
+
+#include <math.h>
+
+#include "screenhack.h"
+
+# include <X11/Xutil.h>
+
+/* I thought it would be faster this way, but it turns out not to be... -jwz */
+#undef USE_XIMAGE
+
+#ifndef USE_XIMAGE
+# undef HAVE_XSHM_EXTENSION /* only applicable when using XImages */
+#endif /* USE_XIMAGE */
+
+
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+# include "xdbe.h"
+#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
+
+#ifdef HAVE_XSHM_EXTENSION
+# include "xshm.h"
+#endif /* HAVE_XSHM_EXTENSION */
+
+char *progclass="Interference";
+
+char *defaults [] = {
+ "*count: 3", /* number of waves */
+ "*gridsize: 4", /* pixel size, smaller values for better resolution */
+ "*ncolors: 128", /* number of colours used */
+ "*speed: 30", /* speed of wave origins moving around */
+ "*delay: 30000", /* or something */
+ "*color-shift: 60", /* h in hsv space, smaller values for smaller
+ * color gradients */
+ "*radius: 800", /* wave extent */
+ "*gray: false", /* color or grayscale */
+ "*mono: false", /* monochrome, not very much fun */
+
+ "*doubleBuffer: True",
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+ "*useDBE: True", /* use double buffering extension */
+#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
+
+#ifdef HAVE_XSHM_EXTENSION
+ "*useSHM: True", /* use shared memory extension */
+#endif /* HAVE_XSHM_EXTENSION */
+ 0
+};
+
+XrmOptionDescRec options [] = {
+ { "-count", ".count", XrmoptionSepArg, 0 },
+ { "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
+ { "-gridsize", ".gridsize", XrmoptionSepArg, 0 },
+ { "-speed", ".speed", XrmoptionSepArg, 0 },
+ { "-delay", ".delay", XrmoptionSepArg, 0 },
+ { "-color-shift", ".color-shift", XrmoptionSepArg, 0 },
+ { "-radius", ".radius", XrmoptionSepArg, 0 },
+ { "-gray", ".gray", XrmoptionNoArg, "True" },
+ { "-mono", ".mono", XrmoptionNoArg, "True" },
+ { "-db", ".doubleBuffer", XrmoptionNoArg, "True" },
+ { "-no-db", ".doubleBuffer", XrmoptionNoArg, "False" },
+#ifdef HAVE_XSHM_EXTENSION
+ { "-shm", ".useSHM", XrmoptionNoArg, "True" },
+ { "-no-shm", ".useSHM", XrmoptionNoArg, "False" },
+#endif /* HAVE_XSHM_EXTENSION */
+ { 0, 0, 0, 0 }
+};
+
+int options_size = (sizeof (options) / sizeof (XrmOptionDescRec));
+
+struct inter_source {
+ int x;
+ int y;
+ double x_theta;
+ double y_theta;
+};
+
+struct inter_context {
+ /*
+ * Display-related entries
+ */
+ Display* dpy;
+ Window win;
+
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+ XdbeBackBuffer back_buf;
+#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
+ Pixmap pix_buf;
+
+ GC copy_gc;
+#ifdef USE_XIMAGE
+ XImage *ximage;
+#endif /* USE_XIMAGE */
+
+#ifdef HAVE_XSHM_EXTENSION
+ Bool use_shm;
+ XShmSegmentInfo shm_info;
+#endif /* HAVE_XSHM_EXTENSION */
+
+ /*
+ * Resources
+ */
+ int count;
+ int grid_size;
+ int colors;
+ int speed;
+ int delay;
+ int shift;
+ int radius;
+
+ /*
+ * Drawing-related entries
+ */
+ int w;
+ int h;
+ Colormap cmap;
+ XColor* pal;
+ GC* gcs;
+
+ /*
+ * lookup tables
+ */
+ int* wave_height;
+
+ /*
+ * Interference sources
+ */
+ struct inter_source* source;
+};
+
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+# define TARGET(c) ((c)->back_buf ? (c)->back_buf : \
+ (c)->pix_buf ? (c)->pix_buf : (c)->win)
+#else /* HAVE_DOUBLE_BUFFER_EXTENSION */
+# define TARGET(c) ((c)->pix_buf ? (c)->pix_buf : (c)->win)
+#endif /* !HAVE_DOUBLE_BUFFER_EXTENSION */
+
+void inter_init(Display* dpy, Window win, struct inter_context* c)
+{
+ XWindowAttributes xgwa;
+ double H[3], S[3], V[3];
+ int i;
+ int mono;
+ int gray;
+ XGCValues val;
+ unsigned long valmask = 0;
+ Bool dbuf = get_boolean_resource ("doubleBuffer", "Boolean");
+
+ memset (c, 0, sizeof(*c));
+
+ c->dpy = dpy;
+ c->win = win;
+
+ XGetWindowAttributes(c->dpy, c->win, &xgwa);
+ c->w = xgwa.width;
+ c->h = xgwa.height;
+ c->cmap = xgwa.colormap;
+
+#ifdef HAVE_XSHM_EXTENSION
+ c->use_shm = get_boolean_resource("useSHM", "Boolean");
+#endif /* HAVE_XSHM_EXTENSION */
+
+ if (dbuf)
+ {
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+ c->back_buf = xdbe_get_backbuffer (c->dpy, c->win, XdbeUndefined);
+#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
+
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+ if (!c->back_buf)
+#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
+ c->pix_buf = XCreatePixmap (dpy, win, xgwa.width, xgwa.height,
+ xgwa.depth);
+ }
+
+ val.function = GXcopy;
+ c->copy_gc = XCreateGC(c->dpy, TARGET(c), GCFunction, &val);
+
+ c->count = get_integer_resource("count", "Integer");
+ if(c->count < 1)
+ c->count = 1;
+ c->grid_size = get_integer_resource("gridsize", "Integer");
+ if(c->grid_size < 1)
+ c->grid_size = 1;
+ mono = get_boolean_resource("mono", "Boolean");
+ if(!mono) {
+ c->colors = get_integer_resource("ncolors", "Integer");
+ if(c->colors < 2)
+ c->colors = 2;
+ }
+ c->speed = get_integer_resource("speed", "Integer");
+ c->shift = get_float_resource("color-shift", "Float");
+ while(c->shift >= 360.0)
+ c->shift -= 360.0;
+ while(c->shift <= -360.0)
+ c->shift += 360.0;
+ c->radius = get_integer_resource("radius", "Integer");;
+ if(c->radius < 1)
+ c->radius = 1;
+
+#ifdef USE_XIMAGE
+
+ c->ximage = 0;
+
+# ifdef HAVE_XSHM_EXTENSION
+ if (c->use_shm)
+ {
+ c->ximage = create_xshm_image(dpy, xgwa.visual, xgwa.depth,
+ ZPixmap, 0, &c->shm_info,
+ xgwa.width, c->grid_size);
+ if (!c->ximage)
+ c->use_shm = False;
+ }
+# endif /* HAVE_XSHM_EXTENSION */
+
+ if (!c->ximage)
+ {
+ c->ximage =
+ XCreateImage (dpy, xgwa.visual,
+ xgwa.depth, ZPixmap, 0, 0, /* depth, fmt, offset, data */
+ xgwa.width, c->grid_size, /* width, height */
+ 8, 0); /* pad, bpl */
+ c->ximage->data = (unsigned char *)
+ calloc(c->ximage->height, c->ximage->bytes_per_line);
+ }
+#endif /* USE_XIMAGE */
+
+ if(!mono) {
+ c->pal = calloc(c->colors, sizeof(XColor));
+
+ srand48(time(NULL));
+
+ gray = get_boolean_resource("gray", "Boolean");
+ if(!gray) {
+ H[0] = frand(360.0);
+ H[1] = H[0] + c->shift < 360.0 ? H[0]+c->shift : H[0] + c->shift-360.0;
+ H[2] = H[1] + c->shift < 360.0 ? H[1]+c->shift : H[1] + c->shift-360.0;
+ S[0] = S[1] = S[2] = 1.0;
+ V[0] = V[1] = V[2] = 1.0;
+ } else {
+ H[0] = H[1] = H[2] = 0.0;
+ S[0] = S[1] = S[2] = 0.0;
+ V[0] = 1.0; V[1] = 0.5; V[2] = 0.0;
+ }
+
+ make_color_loop(c->dpy, c->cmap,
+ H[0], S[0], V[0],
+ H[1], S[1], V[1],
+ H[2], S[2], V[2],
+ c->pal, &(c->colors),
+ True, False);
+ if(c->colors < 2) { /* color allocation failure */
+ mono = 1;
+ free(c->pal);
+ }
+ }
+
+ if(mono) { /* DON'T else this with the previous if! */
+ c->colors = 2;
+ c->pal = calloc(2, sizeof(XColor));
+ c->pal[0].pixel = BlackPixel(c->dpy, DefaultScreen(c->dpy));
+ c->pal[1].pixel = WhitePixel(c->dpy, DefaultScreen(c->dpy));
+ }
+
+ valmask = GCForeground;
+ c->gcs = calloc(c->colors, sizeof(GC));
+ for(i = 0; i < c->colors; i++) {
+ val.foreground = c->pal[i].pixel;
+ c->gcs[i] = XCreateGC(c->dpy, TARGET(c), valmask, &val);
+ }
+
+ c->wave_height = calloc(c->radius, sizeof(int));
+ for(i = 0; i < c->radius; i++) {
+ float max =
+ ((float)c->colors) *
+ ((float)c->radius - (float)i) /
+ ((float)c->radius);
+ c->wave_height[i] =
+ (int)
+ ((max + max*cos((double)i/50.0)) / 2.0);
+ }
+
+ c->source = calloc(c->count, sizeof(struct inter_source));
+ for(i = 0; i < c->count; i++) {
+ c->source[i].x_theta = frand(2.0)*3.14159;
+ c->source[i].y_theta = frand(2.0)*3.14159;
+ }
+
+}
+
+#define source_x(c, i) \
+ (c->w/2 + ((int)(cos(c->source[i].x_theta)*((float)c->w/2.0))))
+#define source_y(c, i) \
+ (c->h/2 + ((int)(cos(c->source[i].y_theta)*((float)c->h/2.0))))
+
+/*
+ * this is rather suboptimal. the sqrt() doesn't seem to be a big
+ * performance hit, but all those separate XFillRectangle()'s are.
+ * hell, it's just a quick hack anyway -- if someone wishes to tune
+ * it, go ahead!
+ */
+
+void do_inter(struct inter_context* c)
+{
+ int i, j, k;
+ int result;
+ int dist;
+ int g;
+
+ int dx, dy;
+
+ for(i = 0; i < c->count; i++) {
+ c->source[i].x_theta += (c->speed/1000.0);
+ if(c->source[i].x_theta > 2.0*3.14159)
+ c->source[i].x_theta -= 2.0*3.14159;
+ c->source[i].y_theta += (c->speed/1000.0);
+ if(c->source[i].y_theta > 2.0*3.14159)
+ c->source[i].y_theta -= 2.0*3.14159;
+ c->source[i].x = source_x(c, i);
+ c->source[i].y = source_y(c, i);
+ }
+
+ g = c->grid_size;
+
+ for(j = 0; j < c->h/g; j++) {
+ for(i = 0; i < c->w/g; i++) {
+ result = 0;
+ for(k = 0; k < c->count; k++) {
+ dx = i*g + g/2 - c->source[k].x;
+ dy = j*g + g/2 - c->source[k].y;
+ dist = sqrt(dx*dx + dy*dy); /* what's the performance penalty here? */
+ result += (dist > c->radius ? 0 : c->wave_height[dist]);
+ }
+ result %= c->colors;
+
+#ifdef USE_XIMAGE
+ /* Fill in these `gridsize' horizontal bits in the scanline */
+ for(k = 0; k < g; k++)
+ XPutPixel(c->ximage, (g*i)+k, 0, c->pal[result].pixel);
+
+#else /* !USE_XIMAGE */
+ XFillRectangle(c->dpy, TARGET(c), c->gcs[result], g*i, g*j, g, g);
+#endif /* !USE_XIMAGE */
+ }
+
+#ifdef USE_XIMAGE
+
+ /* Only the first scanline of the image has been filled in; clone that
+ scanline to the rest of the `gridsize' lines in the ximage */
+ for(k = 0; k < (g-1); k++)
+ memcpy(c->ximage->data + (c->ximage->bytes_per_line * (k + 1)),
+ c->ximage->data + (c->ximage->bytes_per_line * k),
+ c->ximage->bytes_per_line);
+
+ /* Move the bits for this horizontal stripe to the server. */
+# ifdef HAVE_XSHM_EXTENSION
+ if (c->use_shm)
+ XShmPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
+ 0, 0, 0, g*j, c->ximage->width, c->ximage->height,
+ False);
+ else
+# endif /* HAVE_XSHM_EXTENSION */
+ XPutImage(c->dpy, TARGET(c), c->copy_gc, c->ximage,
+ 0, 0, 0, g*j, c->ximage->width, c->ximage->height);
+
+#endif /* USE_XIMAGE */
+ }
+
+#ifdef HAVE_DOUBLE_BUFFER_EXTENSION
+ if (c->back_buf)
+ {
+ XdbeSwapInfo info[1];
+ info[0].swap_window = c->win;
+ info[0].swap_action = XdbeUndefined;
+ XdbeSwapBuffers(c->dpy, info, 1);
+ }
+ else
+#endif /* HAVE_DOUBLE_BUFFER_EXTENSION */
+ if (c->pix_buf)
+ {
+ XCopyArea (c->dpy, c->pix_buf, c->win, c->copy_gc,
+ 0, 0, c->w, c->h, 0, 0);
+ }
+
+ XSync(c->dpy, False);
+}
+
+void screenhack(Display *dpy, Window win)
+{
+ struct inter_context c;
+ int delay;
+
+ delay = get_integer_resource("delay", "Integer");
+
+ inter_init(dpy, win, &c);
+ while(1) {
+ do_inter(&c);
+ screenhack_handle_events (dpy);
+ if(delay) usleep(delay);
+ }
+}
projects / xscreensaver / blobdiff