/* (c) 2021 Aaron Taylor <ataylor at subgeniuskitty dot com> */
/* See LICENSE.txt file for copyright and license details. */
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
/* Various X resources */
/* These hold the pixel value of the foreground and background colors in */
/* the same format as an XColor struct's "pixel" member. */
/* This Pixmap will eventually hold the entire evolution of the CA. The */
/* displayed portion of the CA's evolution is merely a viewport into this */
Pixmap evolution_history
;
/* Together, these three values define the display viewport into the */
/* 'evolution_history' Pixmap. The pair 'dpy_width' and 'dpy_height' are */
/* simply the width and height of the display window. They remain */
/* unchanged during normal operation. However, 'ypos' tracks the location */
/* of the viewport in the 'evolution_history'. It must always keep the */
/* newest generation onscreen and display as much history as possible. */
int dpy_width
, dpy_height
, ypos
;
/* In the 'current_generation' array, the value True means a cell is */
/* alive. We only need to track the current generation since our rulesets */
/* never consider older generations. Anything older can be rendered to */
/* the 'evolution_history' Pixmap and subsequently ignored. */
Bool
* current_generation
;
/* When randomizing the seed generation, we can specify a population */
/* density, or we can restrict to a single living cell. */
/* For more information on the encoding used for rule_number and on the */
/* method used to apply it: https://en.wikipedia.org/wiki/Wolfram_code */
/* At the end of the simulation, the user is given time to admire the */
/* output. Delay is available to user as CLI option. */
Bool admiration_in_progress
;
size_t admiration_delay
; /* ...in microseconds. */
/* The following values correspond directly to independent CLI options. */
uint8_t rule_requested
; /* Note: Repurposing Rule 0 as null value. */
int cell_size
; /* If cell_size=N then draw NxN pixels per cell. */
int delay_microsec
; /* ...between calls to WolframAutomata_draw(). */
int num_generations
; /* Reset simulation after this many generations. */
/* Not strictly necessary, but makes some code easier to read. */
enum seed_population seed
;
static const struct curated_ruleset curated_ruleset_list
[] = {
/* The type 'unsigned short' comes from the XColor struct definition, */
/* unsigned long pixel; */
/* unsigned short red, green, blue; */
/* The red, green, and blue values are always in the range 0 to 65535 */
/* inclusive, independent of the number of bits actually used in the */
/* display hardware. The server scales these values to the range used */
/* by the hardware. Black is represented by (0,0,0), and white is */
/* represented by (65535,65535,65535). */
unsigned short fg_red
, fg_green
, fg_blue
;
unsigned short bg_red
, bg_green
, bg_blue
;
static const struct color_pair color_list
[] = {
/* For mapping X11 color names to RGB values: */
/* https://www.ehdp.com/methods/x11-color-names-rgb-values.htm */
/* Remember that our values range from 0-65535 inclusive, so scale the */
/* usual 0-255 range accordingly. */
/* +---------------------------------------+ */
/* | foreground | | background | */
/* | red,green,blue | | red,green,blue | */
{65535, 0, 0, 0, 0, 0}, /* {"red", "black"}, */
{32767,32767, 0, 0, 0, 0}, /* {"olive", "black"}, */
{ 0,32767,32767, 0, 0, 0}, /* {"teal", "black"}, */
{27524,22937,52428, 0, 0, 0}, /* {"slateblue", "black"}, */
{60947,33422,60947, 0, 0, 0}, /* {"violet", "black"}, */
{41287, 8519,61602, 0, 0, 0}, /* {"purple", "black"}, */
{65535,65535,65535, 0, 0, 0}, /* {"white", "black"}, */
{65535,65535,65535, 0,25558, 0}, /* {"white", "darkgreen"}, */
{65535,65535,65535, 36044, 0,36044}, /* {"white", "darkmagenta"}, */
{65535,65535,65535, 36044, 0, 0}, /* {"white", "darkred"}, */
{65535,65535,65535, 0, 0,36044}, /* {"white", "darkblue"}, */
{11796,20315,20315, 36494,65535,65535}, /* {"darkslategray", "darkslategray1"}, */
{45219,50461,57015, 11796,20315,20315}, /* {"lightsteelblue", "darkslategray"}, */
{10023,16448,35723, 16383,26869,57670}, /* {"royalblue4", "royalblue"}, */
{61166,57311,52428, 35723,33667,30840}, /* {"antiquewhite2", "antiquewhite4"}, */
{51914,65535,28784, 21626,27524,11796}, /* {"darkolivegreen1", "darkolivegreen"}, */
{49601,65535,49601, 26985,35723,26985}, /* {"darkseagreen1", "darkseagreen4"}, */
{65535,49151,52428, 36044, 0, 0}, /* {"pink", "darkred"}, */
{44563,55704,58981, 0,25558, 0}, /* {"lightblue", "darkgreen"}, */
{65535, 0, 0, 0, 0,65535}, /* {"red", "blue"}, */
{65535, 0, 0, 0,25558, 0}, /* {"red", "darkgreen"}, */
{ 0,65535,65535, 0,32767,32767}, /* {"aqua", "teal"}, */
{ 0, 0,36044, 0,32767,32767}, /* {"darkblue", "teal"}, */
{61602,58981,32767, 11796,36044,22281}, /* {"khaki", "seagreen"}, */
{61602,58981,32767, 21626,27524,11796}, /* {"khaki", "darkolivegreen"}, */
{30801,34733,39321, 11796,20315,20315}, /* {"lightslategray", "darkslategray"}, */
{65535,25558,18349, 11796,20315,20315}, /* {"tomato", "darkslategray"}, */
{65535,25558,18349, 0,36044,36044} /* {"tomato", "darkcyan"} */
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
generate_random_seed(struct state
* state
)
for (i
= 0; i
< state
->number_of_cells
; i
++) {
state
->current_generation
[i
] = ((random() % 100) < state
->population_density
) ? True
: False
;
/* This function sanitizes the index used to access cells in a generation. */
/* Specifically, it wraps the index, creating a circular universe for the */
/* cells and ensuring every cell has two neighbors. */
sindex(struct state
* state
, int index
)
index
+= state
->number_of_cells
;
while (index
>= state
->number_of_cells
) {
index
-= state
->number_of_cells
;
/* For more information on the encoding used for state->rule_number and on */
/* the method used to apply it: https://en.wikipedia.org/wiki/Wolfram_code */
calculate_cell(struct state
* state
, int cell_id
)
uint8_t cell_pattern
= 0;
for (i
= -1; i
< 2; i
++) {
cell_pattern
= cell_pattern
<< 1;
if (state
->current_generation
[sindex(state
, cell_id
+i
)] == True
) {
if ((state
->rule_number
>> cell_pattern
) & 1) {
render_current_generation(struct state
* state
)
for (xpos
= 0; xpos
< state
->number_of_cells
; xpos
++) {
if (state
->current_generation
[xpos
] == True
) {
XFillRectangle(state
->dpy
, state
->evolution_history
, state
->gc
, xpos
*state
->cell_size
, state
->ypos
, state
->cell_size
, state
->cell_size
);
XSetForeground(state
->dpy
, state
->gc
, state
->bg
);
XFillRectangle(state
->dpy
, state
->evolution_history
, state
->gc
, xpos
*state
->cell_size
, state
->ypos
, state
->cell_size
, state
->cell_size
);
XSetForeground(state
->dpy
, state
->gc
, state
->fg
);
/* -------------------------------------------------------------------------- */
/* Screenhack API Functions */
/* -------------------------------------------------------------------------- */
WolframAutomata_event(Display
* dpy
, Window win
, void * closure
, XEvent
* event
)
WolframAutomata_free(Display
* dpy
, Window win
, void * closure
)
struct state
* state
= closure
;
XFreeGC(state
->dpy
, state
->gc
);
XFreePixmap(state
->dpy
, state
->evolution_history
);
free(state
->current_generation
);
WolframAutomata_init(Display
* dpy
, Window win
)
struct state
* state
= calloc(1, sizeof(*state
));
fprintf(stderr
, "ERROR: Failed to calloc() for state struct in WolframAutomata_init().\n");
const struct curated_ruleset
* curated_ruleset
= NULL
;
XGetWindowAttributes(state
->dpy
, state
->win
, &xgwa
);
state
->dpy_width
= xgwa
.width
;
state
->dpy_height
= xgwa
.height
;
state
->admiration_delay
= 5000000;
state
->admiration_in_progress
= False
;
/* Set foreground and background colors for active/inactive cells. Either */
/* the user provided an index into the pre-defined color_list[] or a */
/* random entry from that same array should be selected. */
size_t color_index
= get_integer_resource(state
->dpy
, "color-index", "Integer");
color_index
= random() % sizeof(color_list
)/sizeof(color_list
[0]);
} else if (color_index
>= sizeof(color_list
)/sizeof(color_list
[0])) {
fprintf(stderr
, "WARNING: Color index out of range.\n");
fg
.red
= color_list
[color_index
].fg_red
;
fg
.green
= color_list
[color_index
].fg_green
;
fg
.blue
= color_list
[color_index
].fg_blue
;
bg
.red
= color_list
[color_index
].bg_red
;
bg
.green
= color_list
[color_index
].bg_green
;
bg
.blue
= color_list
[color_index
].bg_blue
;
/* TODO: Since I 'alloc', presumably I must also 'free' these colors */
/* at some point. Where/how? I don't want to eventually crash my */
/* X server after months of use. */
XAllocColor(state
->dpy
, xgwa
.colormap
, &fg
);
XAllocColor(state
->dpy
, xgwa
.colormap
, &bg
);
state
->fg
= gcv
.foreground
= fg
.pixel
;
state
->bg
= gcv
.background
= bg
.pixel
;
state
->gc
= XCreateGC(state
->dpy
, state
->win
, GCForeground
, &gcv
);
/* Set the size of each simulated cell to NxN pixels for cell_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
->cell_size
= 1 << (random() % 6);
state
->cell_size
= get_integer_resource(state
->dpy
, "pixel-size", "Integer");
if (state
->cell_size
< 1) state
->cell_size
= 1;
if (state
->cell_size
> state
->dpy_width
) state
->cell_size
= state
->dpy_width
;
/* Larger cell sizes won't always evenly divide the number of pixels in */
/* our window. In order to avoid a black stripe down the edge, '+1' here */
/* to ensure we are slightly oversize rather than undersize. */
state
->number_of_cells
= (state
->dpy_width
/ state
->cell_size
) + 1;
/* 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->cell_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->cell_size=9, then it takes one right shift to */
/* reach state->cell_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 cell_size_temp
= state
->cell_size
;
while (cell_size_temp
> 4) {
/* 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
);
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->cell_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
->cell_size
);
/* Ensure selected value is large enough to at least fill the screen. */
/* Cast to avoid overflow. */
if ((long)state
->num_generations
* (long)state
->cell_size
< state
->dpy_height
) {
state
->num_generations
= (state
->dpy_height
/ state
->cell_size
) + 1;
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. */
if (state
->num_generations
< 0) state
->num_generations
= 2;
/* The maximum number of generations is cell_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
->cell_size
> 10000) {
state
->num_generations
= 10000 / state
->cell_size
;
/* Time to figure out which rule to use for this simulation. */
/* We ignore any weirdness resulting from the following cast since every */
/* bit pattern is also a valid rule; if the user provides weird input, */
/* then we'll return weird (but well-defined!) output. */
state
->rule_requested
= (uint8_t) get_integer_resource(state
->dpy
, "rule-requested", "Integer");
state
->rule_random
= get_boolean_resource(state
->dpy
, "rule-random", "Boolean");
/* Through the following set of branches, we enforce CLI flag precedence. */
if (state
->rule_random
) {
/* If this flag is set, the user wants truly random rules rather than */
/* random rules from a curated list. */
state
->rule_number
= (uint8_t) random();
} else if (state
->rule_requested
!= 0) {
/* Rule 0 is terribly uninteresting, so we are reusing it as a 'null' */
/* value and hoping nobody notices. Finding a non-zero value means */
/* the user requested a specific rule. Use it. */
state
->rule_number
= state
->rule_requested
;
/* No command-line options were specified, so select rules randomly */
/* from a curated list. */
size_t number_of_array_elements
= sizeof(curated_ruleset_list
)/sizeof(curated_ruleset_list
[0]);
curated_ruleset
= &curated_ruleset_list
[random() % number_of_array_elements
];
state
->rule_number
= curated_ruleset
->rule
;
/* Time to construct the seed generation for this simulation. */
state
->population_single
= get_boolean_resource(state
->dpy
, "population-single", "Boolean");
state
->population_density
= get_integer_resource(state
->dpy
, "population-density", "Integer");
if (state
->population_density
< 0 || state
->population_density
> 100) state
->population_density
= 50;
state
->current_generation
= calloc(1, sizeof(*state
->current_generation
)*state
->number_of_cells
);
if (!state
->current_generation
) {
fprintf(stderr
, "ERROR: Failed to calloc() for cell generation in WolframAutomata_init().\n");
/* If we're using a curated ruleset, ignore any CLI flags related to */
/* setting the seed generation, instead drawing that information from */
/* the curated ruleset. */
switch (curated_ruleset
->seed
) {
case random_cell
: generate_random_seed(state
); break;
case middle_cell
: state
->current_generation
[state
->number_of_cells
/2] = True
; break;
case edge_cell
: state
->current_generation
[0] = True
; break;
/* If we're not using a curated ruleset, process any relevant flags */
/* from the user, falling back to a random seed generation if nothing */
if (state
->population_single
) {
state
->current_generation
[0] = True
;
generate_random_seed(state
);
state
->evolution_history
= XCreatePixmap(state
->dpy
, state
->win
, state
->dpy_width
, state
->num_generations
*state
->cell_size
, xgwa
.depth
);
/* Pixmap contents are undefined after creation. Explicitly set a black */
/* background by drawing a black rectangle over the entire pixmap. */
XAllocNamedColor(state
->dpy
, DefaultColormapOfScreen(DefaultScreenOfDisplay(state
->dpy
)), "black", &blacks
, &blackx
);
XSetForeground(state
->dpy
, state
->gc
, blacks
.pixel
);
XFillRectangle(state
->dpy
, state
->evolution_history
, state
->gc
, 0, 0, state
->dpy_width
, state
->num_generations
*state
->cell_size
);
XSetForeground(state
->dpy
, state
->gc
, state
->fg
);
render_current_generation(state
);
state
->ypos
+= state
->cell_size
;
WolframAutomata_draw(Display
* dpy
, Window win
, void * closure
)
struct state
* state
= closure
;
/* Calculate and record new generation. */
Bool new_generation
[state
->dpy_width
];
for (xpos
= 0; xpos
< state
->number_of_cells
; xpos
++) {
new_generation
[xpos
] = calculate_cell(state
, xpos
);
for (xpos
= 0; xpos
< state
->number_of_cells
; xpos
++) {
state
->current_generation
[xpos
] = new_generation
[xpos
];
render_current_generation(state
);
/* Check for end of simulation. */
if (state
->ypos
/state
->cell_size
< state
->num_generations
-1) {
state
->ypos
+= state
->cell_size
;
/* We have reached the end of this simulation. Give the user a moment */
/* to bask in the glory of our output, then reset. */
if (state
->admiration_in_progress
) {
WolframAutomata_free(dpy
, win
, state
);
closure
= WolframAutomata_init(dpy
, win
);
state
->admiration_in_progress
= True
;
return state
->admiration_delay
;
/* Calculate vertical offset of current 'window' into the CA's history. */
/* After the CA evolution exceeds our display extents, make window track */
/* current generation, scrolling display to follow newest generation. */
if (state
->ypos
< state
->dpy_height
) {
window_y_offset
= state
->ypos
- (state
->dpy_height
- 1);
/* Render a window into the CA history. */
XCopyArea(state
->dpy
, state
->evolution_history
, state
->win
, state
->gc
, 0, window_y_offset
, state
->dpy_width
, state
->dpy_height
, 0, 0);
return state
->delay_microsec
;
static const char * WolframAutomata_defaults
[] = {
"*num-generations: 5000",
"*population-density: 50",
"*population-single: False",
"*random-cellsize: False",
static XrmOptionDescRec WolframAutomata_options
[] = {
{ "-delay-usec", ".delay-usec", XrmoptionSepArg
, 0 },
{ "-num-generations", ".num-generations", XrmoptionSepArg
, 0 },
{ "-pixel-size", ".pixel-size", XrmoptionSepArg
, 0 },
{ "-color-index", ".color-index", XrmoptionSepArg
, 0 },
{ "-population-density", ".population-density", XrmoptionSepArg
, 0 },
{ "-population-single", ".population-single", XrmoptionNoArg
, "True" },
{ "-random-cellsize", ".random-pixel-size", XrmoptionNoArg
, "True" },
{ "-random-delay", ".random-delay", XrmoptionNoArg
, "True" },
{ "-random-length", ".random-num-generations", XrmoptionNoArg
, "True" },
{ "-random-rule", ".rule-random", XrmoptionNoArg
, "True" },
{ "-rule", ".rule-requested", XrmoptionSepArg
, 0 },
WolframAutomata_reshape(Display
* dpy
, Window win
, void * closure
, unsigned int w
, unsigned int h
)
struct state
* state
= closure
;
XGetWindowAttributes(state
->dpy
, state
->win
, &xgwa
);
/* Only restart the simulation if the window changed size. */
if (state
->dpy_width
!= xgwa
.width
|| state
->dpy_height
!= xgwa
.height
) {
WolframAutomata_free(dpy
, win
, closure
);
closure
= WolframAutomata_init(dpy
, win
);
XSCREENSAVER_MODULE ("1D Nearest-Neighbor Cellular Automata", WolframAutomata
)