+++ /dev/null
-/* critical -- Self-organizing-criticality display hack for XScreenSaver
- * Copyright (C) 1998, 1999 Martin Pool <mbp@humbug.org.au>
- *
- * 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.
- *
- * See `critical.man' for more information.
- *
- * Revision history:
- * 13 Nov 1998: Initial version, Martin Pool <mbp@humbug.org.au>
- */
-
-#include "screenhack.h"
-#include "erase.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-
-char *progclass = "Critical";
-
-
-typedef struct {
- int width, height; /* in cells */
- unsigned short *cells;
-} CriticalModel;
-
-
-CriticalModel * model_allocate (int w, int h);
-void model_initialize (CriticalModel *model);
-static void model_step (CriticalModel *model, int *top_x, int *top_y);
-
-
-/* Options this module understands. */
-XrmOptionDescRec options[] = {
- { "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
- { "-delay", ".delay", XrmoptionSepArg, 0 },
- { "-colorscheme", ".colorscheme", XrmoptionSepArg, 0 },
- { "-restart", ".restart", XrmoptionSepArg, 0 },
- { "-cellsize", ".cellsize", XrmoptionSepArg, 0 },
- { "-batchcount", ".batchcount", XrmoptionSepArg, 0 },
- { 0, 0, 0, 0 } /* end */
-};
-
-
-/* Default xrm resources. */
-char *defaults[] = {
- ".background: black",
- "*colorscheme: smooth",
- "*delay: 10000",
- "*ncolors: 64",
- "*restart: 8",
- "*cellsize: 9",
- "*batchcount: 1500",
- 0 /* end */
-};
-
-
-/* Allocate an return a new simulation model datastructure.
- */
-
-CriticalModel *
-model_allocate (int model_w, int model_h)
-{
- CriticalModel *model;
-
- model = malloc (sizeof (CriticalModel));
- if (!model)
- return 0;
-
- model->width = model_w;
- model->height = model_h;
-
- model->cells = malloc (sizeof (int) * model_w * model_h);
- if (!model->cells)
- return 0;
-
- return model;
-}
-
-
-
-/* Initialize the data model underlying the hack.
-
- For the self-organizing criticality hack, this consists of a 2d
- array full of random integers.
-
- I've considered storing the data as (say) a binary tree within a 2d
- array, to make finding the highest value faster at the expense of
- storage space: searching the whole array on each iteration seems a
- little inefficient. However, the screensaver doesn't seem to take
- up many cycles as it is: presumably the search is pretty quick
- compared to the sleeps. The current version uses less than 1% of
- the CPU time of an AMD K6-233. Many machines running X11 at this
- point in time seem to be memory-limited, not CPU-limited.
-
- The root of all evil, and all that.
-*/
-
-
-void
-model_initialize (CriticalModel *model)
-{
- int i;
-
- for (i = model->width * model->height; i >= 0; i--)
- {
- model->cells[i] = (unsigned short) random ();
- }
-}
-
-
-/* Move one step forward in the criticality simulation.
-
- This function locates and returns in (TOP_X, TOP_Y) the location of
- the highest-valued cell in the model. It also replaces that cell
- and it's eight nearest neighbours with new random values.
- Neighbours that fall off the edge of the model are simply
- ignored. */
-static void
-model_step (CriticalModel *model, int *top_x, int *top_y)
-{
- int x, y, i;
- int dx, dy;
- unsigned short top_value;
-
- /* Find the top cell */
- top_value = 0;
- i = 0;
- for (y = 0; y < model->height; y++)
- for (x = 0; x < model->width; x++)
- {
- if (model->cells[i] >= top_value)
- {
- top_value = model->cells[i];
- *top_x = x;
- *top_y = y;
- }
- i++;
- }
-
- /* Replace it and its neighbours with new random values */
- for (dy = -1; dy <= 1; dy++)
- {
- int y = *top_y + dy;
- if (y < 0 || y >= model->height)
- continue;
-
- for (dx = -1; dx <= 1; dx++)
- {
- int x = *top_x + dx;
- if (x < 0 || x >= model->width)
- continue;
-
- model->cells[y * model->width + x] = (unsigned short) random();
- }
- }
-}
-
-
-/* Construct and return in COLORS and N_COLORS a new set of colors,
- depending on the resource settings. */
-void
-setup_colormap (Display *dpy, XWindowAttributes *wattr,
- XColor **colors,
- int *n_colors)
-{
- Bool writable;
- char const * color_scheme;
-
- /* Make a colormap */
- *n_colors = get_integer_resource ("ncolors", "Integer");
- if (*n_colors < 2)
- *n_colors = 2;
-
- *colors = (XColor *) calloc (sizeof(XColor), *n_colors);
- if (!*colors)
- {
- fprintf (stderr, "%s:%d: can't allocate memory for colors\n",
- __FILE__, __LINE__);
- return;
- }
-
- writable = False;
- color_scheme = get_string_resource ("colorscheme", "ColorScheme");
-
- if (!strcmp (color_scheme, "random"))
- {
- make_random_colormap (dpy, wattr->visual,
- wattr->colormap,
- *colors, n_colors,
- True, True, &writable, True);
- }
- else if (!strcmp (color_scheme, "smooth"))
- {
- make_smooth_colormap (dpy, wattr->visual,
- wattr->colormap,
- *colors, n_colors,
- True, &writable, True);
- }
- else
- {
- make_uniform_colormap (dpy, wattr->visual,
- wattr->colormap,
- *colors, n_colors, True,
- &writable, True);
- }
-}
-
-
-
-/* Display a self-organizing criticality screen hack. The program
- runs indefinately on the root window. */
-void
-screenhack (Display *dpy, Window window)
-{
- GC fgc, bgc;
- XGCValues gcv;
- XWindowAttributes wattr;
- int n_colors;
- XColor *colors;
- int model_w, model_h;
- CriticalModel *model;
- int lines_per_color = 10;
- int i_color = 0;
- int x1, y1, x2, y2;
- long delay_usecs;
- int cell_size;
- int batchcount;
-
- /* Number of screens that should be drawn before reinitializing the
- model, and count of the number of screens done so far. */
- int n_restart, i_restart;
-
- /* Find window attributes */
- XGetWindowAttributes (dpy, window, &wattr);
-
- /* Construct the initial model state. */
- cell_size = get_integer_resource ("cellsize", "Integer");
- if (cell_size < 1)
- cell_size = 1;
- if (cell_size >= 100)
- cell_size = 99;
-
- batchcount = get_integer_resource ("batchcount", "Integer");
- if (batchcount < 5)
- batchcount = 5;
-
- model_w = wattr.width / cell_size;
- model_h = wattr.height / cell_size;
-
- model = model_allocate (model_w, model_h);
- if (!model)
- {
- fprintf (stderr, "critical: error preparing the model\n");
- return;
- }
-
- /* make a black gc for the background */
- gcv.foreground = get_pixel_resource ("background", "Background",
- dpy, wattr.colormap);
- bgc = XCreateGC (dpy, window, GCForeground, &gcv);
-
- fgc = XCreateGC (dpy, window, 0, &gcv);
-
- x2 = rand() % model_w;
- y2 = rand() % model_h;
-
- delay_usecs = get_integer_resource ("delay", "Integer");
- n_restart = get_integer_resource ("restart", "Integer");
-
- /* xscreensaver will kill or stop us when the user does something
- * that deserves attention. */
- i_restart = 0;
-
- while (1) {
- int i_batch;
-
- if (!i_restart)
- {
- setup_colormap (dpy, &wattr, &colors, &n_colors);
- model_initialize (model);
- }
-
- for (i_batch = batchcount; i_batch; i_batch--)
- {
- /* Set color */
- if ((i_batch % lines_per_color) == 0)
- {
- i_color = (i_color + 1) % n_colors;
- gcv.foreground = colors[i_color].pixel;
- XChangeGC (dpy, fgc, GCForeground, &gcv);
- }
-
- /* draw a line */
- x1 = x2;
- y1 = y2;
-
- model_step (model, &x2, &y2);
-
- XDrawLine (dpy, window, fgc,
- x1 * cell_size + cell_size/2,
- y1 * cell_size + cell_size/2,
- x2 * cell_size + cell_size/2,
- y2 * cell_size + cell_size/2);
-
- XSync (dpy, False);
- screenhack_handle_events (dpy);
-
- if (delay_usecs)
- usleep (delay_usecs);
- }
-
- i_restart = (i_restart + 1) % n_restart;
- erase_full_window (dpy, window);
- }
-}
-
-
-/*
- * Local variables:
- * c-indent-mode: gnu
- * compile-command "make critical && ./critical"
- * End:
- */
projects / xscreensaver / blobdiff