Added CLI options -random-num-generations, -random-pixel-size, and -random-delay...

diff --git a/hacks/WolframAutomata/WolframAutomata.c b/hacks/WolframAutomata/WolframAutomata.c
index b6da506..35482df 100644 (file)
--- a/hacks/WolframAutomata/WolframAutomata.c
+++ b/hacks/WolframAutomata/WolframAutomata.c
@@ -298,22 +298,83 @@ WolframAutomata_init(Display * dpy, Window win)
     state->bg = gcv.background = get_pixel_resource(state->dpy, xgwa.colormap, "background", "Background");
     state->gc = XCreateGC(state->dpy, state->win, GCForeground, &gcv);
 
     state->bg = gcv.background = get_pixel_resource(state->dpy, xgwa.colormap, "background", "Background");
     state->gc = XCreateGC(state->dpy, state->win, GCForeground, &gcv);
 

-    state->delay_microsec = get_integer_resource(state->dpy, "delay-usec", "Integer");
-    if (state->delay_microsec < 0) state->delay_microsec = 0;
-
-    state->pixel_size = get_integer_resource(state->dpy, "pixel-size", "Integer");
+    /* Set the size of each simulated cell as NxN pixels for pixel_size=N.    */
+    if (get_boolean_resource(state->dpy, "random-pixel-size", "Boolean")) {
+        /* Although we are choosing the pixel size 'randomly', a truly random */
+        /* selection would bias toward large numbers since there are more of  */
+        /* them. To avoid this, we select a random number for a bit shift,    */
+        /* resulting in a pixel size of 1, 2, 4, 8, 16 or 32, equally likely. */
+        state->pixel_size = 1 << (random() % 6);
+    } else {
+        state->pixel_size = get_integer_resource(state->dpy, "pixel-size", "Integer");
+    }

     if (state->pixel_size < 1) state->pixel_size = 1;
     if (state->pixel_size > state->xlim) state->pixel_size = state->xlim;
 
     state->number_of_cells = state->xlim / state->pixel_size;
     // TODO: Do we want to enforce that number_of_cells > 0?
 
     if (state->pixel_size < 1) state->pixel_size = 1;
     if (state->pixel_size > state->xlim) state->pixel_size = state->xlim;
 
     state->number_of_cells = state->xlim / state->pixel_size;
     // TODO: Do we want to enforce that number_of_cells > 0?
 

+    /* Set the delay (in microseconds) between simulation of each generation  */
+    /* of the simulation, also known as the delay between calls to            */
+    /* WolframAutomata_draw(), which simulates one generation per call.       */
+    if (get_boolean_resource(state->dpy, "random-delay", "Boolean")) {
+        /* When randomly setting the delay, the problem is to avoid being too */
+        /* fast or too slow, as well as ensuring slower speeds are chosen     */
+        /* with the same likelihood as faster speeds, as perceived by a       */
+        /* human. By empirical observation, we note that for 1x1 up to 4x4    */
+        /* pixel cell sizes, values for state->delay_microsec between         */
+        /* 2048 (2^11) and 16556 (2^14) produce pleasant scroll rates. To     */
+        /* maintain this appearance, we bitshift state->pixel_size down until */
+        /* it is a maximum of 4x4 pixels in size, record how many bitshifts   */
+        /* took place, and then shift our valid window for                    */
+        /* state->delay_microsec up by an equal number of bitshifts. For      */
+        /* example, if state->pixel_size=9, then it takes one right shift to  */
+        /* reach state->pixel_size=4. Thus, the valid window for              */
+        /* state->delay_microsec becomes 4096 (2^12) up to 32768 (2^15).      */
+        size_t pixel_shift_range = 1;
+        size_t pixel_size_temp = state->pixel_size;
+        while (pixel_size_temp > 4) {
+            pixel_size_temp >>= 1;
+            pixel_shift_range++;
+        }
+        /* In the below line, '3' represents the total range, namely '14-11'  */
+        /* from '2^14' and '2^11' as the endpoints. Similarly, the '11' in    */
+        /* the below line represents the starting point of this range, from   */
+        /* the exponent in '2^11'.                                            */
+        state->delay_microsec = 1 << ((random() % 3) + 11 + pixel_shift_range);
+    } else {
+        state->delay_microsec = get_integer_resource(state->dpy, "delay-usec", "Integer");
+    }
+    if (state->delay_microsec < 0) state->delay_microsec = 0;
+
+    /* Set the number of generations to simulate before wiping the simulation */
+    /* and re-running with new settings.                                      */
+    if (get_boolean_resource(state->dpy, "random-num-generations", "Boolean")) {
+        /* By empirical observation, keep the product                         */
+        /*      state->num_generations * state->pixel_size                    */
+        /* below 10,000 to avoid BadAlloc errors from the X server due to     */
+        /* requesting an enormous pixmap. This value works on both a 12 core  */
+        /* Xeon with 108 GiB of RAM and a Sun Ultra 2 with 2 GiB of RAM.      */
+        state->num_generations = random() % (10000 / state->pixel_size);
+        /* Ensure selected value is large enough to at least fill the screen. */
+        /* Cast to avoid overflow.                                            */
+        if ((long)state->num_generations * (long)state->pixel_size < state->ylim) {
+            state->num_generations = (state->ylim / state->pixel_size) + 1;
+        }
+    } else {
+        state->num_generations = get_integer_resource(state->dpy, "num-generations", "Integer");
+    }

     /* The minimum number of generations is 2 since we must allocate enough   */
     /* space to hold the seed generation and at least one pass through        */
     /* WolframAutomata_draw(), which is where we check whether or not we've   */
     /* reached the end of the pixmap.                                         */
     /* The minimum number of generations is 2 since we must allocate enough   */
     /* space to hold the seed generation and at least one pass through        */
     /* WolframAutomata_draw(), which is where we check whether or not we've   */
     /* reached the end of the pixmap.                                         */

-    state->num_generations = get_integer_resource(state->dpy, "num-generations", "Integer");

     if (state->num_generations < 0) state->num_generations = 2;
     if (state->num_generations < 0) state->num_generations = 2;

+    /* The maximum number of generations is pixel_size dependent. This is a   */
+    /* soft limit and may be increased if you have plenty of RAM (and a       */
+    /* cooperative X server). The value 10,000 was determined empirically.    */
+    if ((long)state->num_generations * (long)state->pixel_size > 10000) {
+        state->num_generations = 10000 / state->pixel_size;
+    }

 
     /* Time to figure out which rule to use for this simulation.              */
     /* We ignore any weirdness resulting from the following cast since every  */
 
     /* Time to figure out which rule to use for this simulation.              */
     /* We ignore any weirdness resulting from the following cast since every  */


@@ -450,6 +511,9 @@ static const char * WolframAutomata_defaults[] = {
     "*rule-random:    False",
     "*population-density:    50",
     "*population-single:    False",
     "*rule-random:    False",
     "*population-density:    50",
     "*population-single:    False",

+    "*random-delay:    False",
+    "*random-pixel-size:    False",
+    "*random-num-generations:    False",

     0
 };
 
     0
 };
 


@@ -465,6 +529,10 @@ static XrmOptionDescRec WolframAutomata_options[] = {
     { "-rule-random",    ".rule-random",    XrmoptionNoArg, "True" },
     { "-population-density",    ".population-density",    XrmoptionSepArg, 0 },
     { "-population-single",    ".population-single",    XrmoptionNoArg, "True" },
     { "-rule-random",    ".rule-random",    XrmoptionNoArg, "True" },
     { "-population-density",    ".population-density",    XrmoptionSepArg, 0 },
     { "-population-single",    ".population-single",    XrmoptionNoArg, "True" },

+    { "-random-delay", ".random-delay", XrmoptionNoArg, "True" },
+    { "-random-pixel-size", ".random-pixel-size", XrmoptionNoArg, "True" },
+    { "-random-num-generations", ".random-num-generations", XrmoptionNoArg, "True" },
+

     { 0, 0, 0, 0 }
 };
 
     { 0, 0, 0, 0 }
 };