+++ /dev/null
-/* munch.c
- * A munching squares implementation for X
- * Tim Showalter <tjs@andrew.cmu.edu>
- *
- * Copyright 1997, Tim Showalter
- * Permission is granted to copy, modify, and use this as long
- * as this notice remains intact. No warranties are expressed or implied.
- * CMU Sucks.
- *
- * Some code stolen from / This is meant to work with
- * xscreensaver, Copyright (c) 1992, 1995, 1996
- * Jamie Zawinski <jwz@jwz.org>
- *
- * 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.
- */
-
-/* Munching Squares is this simplistic, silly screen hack (according
- to HAKMEM, discovered by Jackson Wright in 1962) where you take
- Y = X XOR T and graph it over and over. According to HAKMEM, it
- takes 5 instructions of PDP-1 assembly. This is a little more
- complicated than that, mostly X's fault, but it does some other
- random things.
-
- http://www.inwap.com/pdp10/hbaker/hakmem/hacks.html#item146
- */
-
-#include <math.h>
-/*#include <assert.h>*/
-#include "screenhack.h"
-
-/* flags for random things. Must be < log2(random's maximum), incidentially.
- */
-#define SHIFT_KX (0x01)
-#define SHIFT_KT (0x02)
-#define SHIFT_KY (0x04)
-#define GRAV (0x08)
-
-char *progclass = "Munch";
-
-char *defaults [] = {
- ".background: black",
- ".foreground: white",
- "*delay: 5000",
- "*hold: 100000",
- "*clear: 50",
- "*logminwidth: 7",
- "*shift: True",
- "*xor: True",
- 0
-};
-
-XrmOptionDescRec options [] = {
- { "-delay", ".delay", XrmoptionSepArg, 0 },
- { "-hold", ".hold", XrmoptionSepArg, 0 },
- { "-clear", ".clear", XrmoptionSepArg, "true" },
- { "-shift", ".shift", XrmoptionNoArg, "true" },
- { "-no-shift", ".shift", XrmoptionNoArg, "false" },
- { "-logminwidth", ".logminwidth", XrmoptionSepArg, 0 },
- { "-xor", ".xor", XrmoptionNoArg, "true" },
- { "-no-xor", ".xor", XrmoptionNoArg, "false" },
- { 0, 0, 0, 0 }
-};
-
-
-static GC gc;
-/* only configurable things right now */
-static int delay, hold, clear, logminwidth, shiftk, xor;
-
-static void munchOnce (Display* dpy, Window w,
- int width, /* pixels */
- int atX, int atY, /* pixels */
- int kX, int kT, int kY, /* pixels */
- int grav /* 0 or not */) {
-
- int x, y, t;
- static Colormap cmap;
- XWindowAttributes xgwa;
- XColor fgc;
- int drawX, drawY;
-
- /*
- fprintf(stderr,"Doing width %d at %d %d shift %d %d %d grav %d\n",
- width, atX, atY, kX, kT, kY, grav);
- */
-
- XGetWindowAttributes (dpy, w, &xgwa);
-
- if (!mono_p) {
- /* XXX there are probably bugs with this. */
- cmap = xgwa.colormap;
-
- fgc.red = random() % 65535;
- fgc.green = random() % 65535;
- fgc.blue = random() % 65535;
-
- if (XAllocColor(dpy, cmap, &fgc)) {
- XSetForeground(dpy, gc, fgc.pixel);
- }
- }
-
- /* Finally draw this munching square. */
- for(t = 0; t < width; t++) {
- for(x = 0; x < width; x++) {
- /* figure out the next point */
- y = ((x ^ ((t + kT) % width)) + kY) % width;
-
- drawX = ((x + kX) % width) + atX;
- drawY = (grav ? y + atY : atY + width - 1 - y);
-
- /* used to be bugs where it would draw partially offscreen.
- while that might be a pretty feature, I didn't want it to do
- that yet. if these trigger, please let me know.
- */
-/* assert(drawX >= 0 && drawX < xgwa.width);
- assert(drawY >= 0 && drawY < xgwa.height);
-*/
-
- XDrawPoint(dpy, w, gc, drawX, drawY);
- /* XXX may want to change this to XDrawPoints,
- but it's fast enough without it for the moment. */
-
- }
-
- /* we've drawn one pass' worth of points. let the server catch up
- or this won't be interesting to watch at all. we call this here
- in the hopes of having one whole sequence of dots appear at the
- same time (one for each value of x, surprisingly enough)
- */
- XSync(dpy, False);
- screenhack_handle_events (dpy);
- if (delay) usleep(delay);
- }
-}
-
-/*
- * dumb way to get # of digits in number. Probably faster than actually
- * doing a log and a division, maybe.
- */
-static int dumb_log_2(int k) {
- int r = -1;
- while (k > 0) {
- k >>= 1; r++;
- }
- return r;
-}
-
-/* This parses arguments, initializes the window, etc., and finally starts
- * calling munchOnce ad infinitum.
- */
-void
-screenhack (dpy, w) Display *dpy; Window w;
-{
- int logmaxwidth;
- int maxwidth;
- XWindowAttributes xgwa;
- Colormap cmap;
- XGCValues gcv;
- int n = 0; /* number of squares before we have to clear */
- int randflags;
- int thiswidth;
-
- /* get the dimensions of the window */
- XGetWindowAttributes (dpy, w, &xgwa);
-
- /* We need a square; limit on screen size? */
- /* we want a power of 2 for the width or the munch doesn't fill up.
- */
- logmaxwidth = (int)
- dumb_log_2(xgwa.height < xgwa.width ? xgwa.height : xgwa.width);
-
- maxwidth = 1 << logmaxwidth;
-
- if (logmaxwidth < logminwidth) {
- /* off-by-one error here? Anyone running on < 640x480? */
- fprintf(stderr, "munch: screen too small; use -logminwidth\n");
- fprintf(stderr, "\t(width is %d; log is %d; log must be at least "
- "%d)\n",
- (xgwa.height < xgwa.width ? xgwa.height : xgwa.width),
- logmaxwidth, logminwidth);
- exit(0);
- }
-
- /* create the gc */
- cmap = xgwa.colormap;
- gcv.foreground= get_pixel_resource("foreground","Foreground",
- dpy, cmap);
- gcv.background= get_pixel_resource("background","Background",
- dpy, cmap);
-
- gc = XCreateGC(dpy, w, GCForeground|GCBackground, &gcv);
-
- delay = get_integer_resource ("delay", "Integer");
- if (delay < 0) delay = 0;
-
- hold = get_integer_resource ("hold", "Integer");
- if (hold < 0) hold = 0;
-
- clear = get_integer_resource ("clear", "Integer");
- if (clear < 0) clear = 0;
-
- logminwidth = get_integer_resource ("logminwidth", "Integer");
- if (logminwidth < 2) logminwidth = 2;
-
- shiftk = get_boolean_resource("shift", "Boolean");
-
- xor = get_boolean_resource("xor", "Boolean");
-
- /* always draw xor on mono. */
- if (mono_p || xor) {
- XSetFunction(dpy, gc, GXxor);
- }
-
- for(;;) {
- /* saves some calls to random. big deal */
- randflags = random();
-
- /* choose size -- power of two */
- thiswidth = 1 << (logminwidth +
- (random() % (1 + logmaxwidth - logminwidth)));
-
- munchOnce(dpy, w,
- thiswidth, /* Width, in pixels */
-
- /* draw at this location */
- (random() % (xgwa.width <= thiswidth ? 1
- : xgwa.width - thiswidth)),
- (random() % (xgwa.height <= thiswidth ? 1
- : xgwa.width - thiswidth)),
-
- /* wrap-around by these values; no need to %
- as we end up doing that later anyway*/
- ((shiftk && (randflags & SHIFT_KX))
- ? (random() % thiswidth) : 0),
- ((shiftk && (randflags & SHIFT_KT))
- ? (random() % thiswidth) : 0),
- ((shiftk && (randflags & SHIFT_KY))
- ? (random() % thiswidth) : 0),
-
- /* set the gravity of the munch, or rather,
- which direction we draw stuff in. */
- (randflags & GRAV)
- );
-
- screenhack_handle_events (dpy);
- if (hold) usleep(hold);
-
- if (clear && ++n >= clear) {
- XClearWindow(dpy, w);
- n = 0;
- }
- }
-}
projects / xscreensaver / blobdiff