ref: 201b32983b5cd1f904da3614ee9136cfeec59818
dir: /emcc.c/
/*
* emcc.c: the C component of an Emscripten-based web/Javascript front
* end for Puzzles.
*
* The Javascript parts of this system live in emcclib.js and
* emccpre.js. It also depends on being run in the context of a web
* page containing an appropriate collection of bits and pieces (a
* canvas, some buttons and links etc), which is generated for each
* puzzle by the script html/jspage.pl.
*/
/*
* Further thoughts on possible enhancements:
*
* - I think it might be feasible to have these JS puzzles permit
* loading and saving games in disk files. Saving would be done by
* constructing a data: URI encapsulating the save file, and then
* telling the browser to visit that URI with the effect that it
* would naturally pop up a 'where would you like to save this'
* dialog box. Loading, more or less similarly, might be feasible
* by using the DOM File API to ask the user to select a file and
* permit us to see its contents.
*
* - I should think about whether these webified puzzles can support
* touchscreen-based tablet browsers (assuming there are any that
* can cope with the reasonably modern JS and run it fast enough to
* be worthwhile).
*
* - think about making use of localStorage. It might be useful to
* let the user save games into there as an alternative to disk
* files - disk files are all very well for getting the save right
* out of your browser to (e.g.) email to me as a bug report, but
* for just resuming a game you were in the middle of, you'd
* probably rather have a nice simple 'quick save' and 'quick load'
* button pair. Also, that might be a useful place to store
* preferences, if I ever get round to writing a preferences UI.
*
* - some CSS to make the button bar and configuration dialogs a
* little less ugly would probably not go amiss.
*
* - this is a downright silly idea, but it does occur to me that if
* I were to write a PDF output driver for the Puzzles printing
* API, then I might be able to implement a sort of 'printing'
* feature in this front end, using data: URIs again. (Ask the user
* exactly what they want printed, then construct an appropriate
* PDF and embed it in a gigantic data: URI. Then they can print
* that using whatever they normally use to print PDFs!)
*/
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include "puzzles.h"
/*
* Extern references to Javascript functions provided in emcclib.js.
*/
extern void js_debug(const char *);
extern void js_error_box(const char *message);
extern void js_remove_type_dropdown(void);
extern void js_remove_solve_button(void);
extern void js_add_preset(const char *name);
extern int js_get_selected_preset(void);
extern void js_select_preset(int n);
extern void js_get_date_64(unsigned *p);
extern void js_update_permalinks(const char *desc, const char *seed);
extern void js_enable_undo_redo(int undo, int redo);
extern void js_activate_timer();
extern void js_deactivate_timer();
extern void js_canvas_start_draw(void);
extern void js_canvas_draw_update(int x, int y, int w, int h);
extern void js_canvas_end_draw(void);
extern void js_canvas_draw_rect(int x, int y, int w, int h,
const char *colour);
extern void js_canvas_clip_rect(int x, int y, int w, int h);
extern void js_canvas_unclip(void);
extern void js_canvas_draw_line(float x1, float y1, float x2, float y2,
int width, const char *colour);
extern void js_canvas_draw_poly(int *points, int npoints,
const char *fillcolour,
const char *outlinecolour);
extern void js_canvas_draw_circle(int x, int y, int r,
const char *fillcolour,
const char *outlinecolour);
extern int js_canvas_find_font_midpoint(int height, const char *fontptr);
extern void js_canvas_draw_text(int x, int y, int halign,
const char *colptr, const char *fontptr,
const char *text);
extern int js_canvas_new_blitter(int w, int h);
extern void js_canvas_free_blitter(int id);
extern void js_canvas_copy_to_blitter(int id, int x, int y, int w, int h);
extern void js_canvas_copy_from_blitter(int id, int x, int y, int w, int h);
extern void js_canvas_make_statusbar(void);
extern void js_canvas_set_statusbar(const char *text);
extern void js_canvas_set_size(int w, int h);
extern void js_dialog_init(const char *title);
extern void js_dialog_string(int i, const char *title, const char *initvalue);
extern void js_dialog_choices(int i, const char *title, const char *choicelist,
int initvalue);
extern void js_dialog_boolean(int i, const char *title, int initvalue);
extern void js_dialog_launch(void);
extern void js_dialog_cleanup(void);
extern void js_focus_canvas(void);
/*
* Call JS to get the date, and use that to initialise our random
* number generator to invent the first game seed.
*/
void get_random_seed(void **randseed, int *randseedsize)
{
unsigned *ret = snewn(2, unsigned);
js_get_date_64(ret);
*randseed = ret;
*randseedsize = 2*sizeof(unsigned);
}
/*
* Fatal error, called in cases of complete despair such as when
* malloc() has returned NULL.
*/
void fatal(char *fmt, ...)
{
char buf[512];
va_list ap;
strcpy(buf, "puzzle fatal error: ");
va_start(ap, fmt);
vsnprintf(buf+strlen(buf), sizeof(buf)-strlen(buf), fmt, ap);
va_end(ap);
js_error_box(buf);
}
void debug_printf(char *fmt, ...)
{
char buf[512];
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
js_debug(buf);
}
/*
* Helper function that makes it easy to test strings that might be
* NULL.
*/
int strnullcmp(const char *a, const char *b)
{
if (a == NULL || b == NULL)
return a != NULL ? +1 : b != NULL ? -1 : 0;
return strcmp(a, b);
}
/*
* HTMLish names for the colours allocated by the puzzle.
*/
char **colour_strings;
int ncolours;
/*
* The global midend object.
*/
midend *me;
/* ----------------------------------------------------------------------
* Timing functions.
*/
int timer_active = FALSE;
void deactivate_timer(frontend *fe)
{
js_deactivate_timer();
timer_active = FALSE;
}
void activate_timer(frontend *fe)
{
if (!timer_active) {
js_activate_timer();
timer_active = TRUE;
}
}
void timer_callback(double tplus)
{
if (timer_active)
midend_timer(me, tplus);
}
/* ----------------------------------------------------------------------
* Helper functions to resize the canvas, and variables to remember
* its size for other functions (e.g. trimming blitter rectangles).
*/
static int canvas_w, canvas_h;
/* Called when we resize as a result of changing puzzle settings */
static void resize(void)
{
int w, h;
w = h = INT_MAX;
midend_size(me, &w, &h, FALSE);
js_canvas_set_size(w, h);
canvas_w = w;
canvas_h = h;
}
/* Called from JS when the user uses the resize handle */
void resize_puzzle(int w, int h)
{
midend_size(me, &w, &h, TRUE);
if (canvas_w != w || canvas_h != h) {
js_canvas_set_size(w, h);
canvas_w = w;
canvas_h = h;
midend_force_redraw(me);
}
}
/* Called from JS when the user uses the restore button */
void restore_puzzle_size(int w, int h)
{
midend_reset_tilesize(me);
resize();
midend_force_redraw(me);
}
/*
* HTML doesn't give us a default frontend colour of its own, so we
* just make up a lightish grey ourselves.
*/
void frontend_default_colour(frontend *fe, float *output)
{
output[0] = output[1] = output[2] = 0.9F;
}
/*
* Helper function called from all over the place to ensure the undo
* and redo buttons get properly enabled and disabled after every move
* or undo or new-game event.
*/
static void update_undo_redo(void)
{
js_enable_undo_redo(midend_can_undo(me), midend_can_redo(me));
}
/*
* Mouse event handlers called from JS.
*/
void mousedown(int x, int y, int button)
{
button = (button == 0 ? LEFT_BUTTON :
button == 1 ? MIDDLE_BUTTON : RIGHT_BUTTON);
midend_process_key(me, x, y, button);
update_undo_redo();
}
void mouseup(int x, int y, int button)
{
button = (button == 0 ? LEFT_RELEASE :
button == 1 ? MIDDLE_RELEASE : RIGHT_RELEASE);
midend_process_key(me, x, y, button);
update_undo_redo();
}
void mousemove(int x, int y, int buttons)
{
int button = (buttons & 2 ? MIDDLE_DRAG :
buttons & 4 ? RIGHT_DRAG : LEFT_DRAG);
midend_process_key(me, x, y, button);
update_undo_redo();
}
/*
* Keyboard handler called from JS.
*/
void key(int keycode, int charcode, const char *key, const char *chr,
int shift, int ctrl)
{
int keyevent = -1;
if (!strnullcmp(key, "Backspace") || !strnullcmp(key, "Del") ||
keycode == 8 || keycode == 46) {
keyevent = 127; /* Backspace / Delete */
} else if (!strnullcmp(key, "Enter") || keycode == 13) {
keyevent = 13; /* return */
} else if (!strnullcmp(key, "Left") || keycode == 37) {
keyevent = CURSOR_LEFT;
} else if (!strnullcmp(key, "Up") || keycode == 38) {
keyevent = CURSOR_UP;
} else if (!strnullcmp(key, "Right") || keycode == 39) {
keyevent = CURSOR_RIGHT;
} else if (!strnullcmp(key, "Down") || keycode == 40) {
keyevent = CURSOR_DOWN;
} else if (!strnullcmp(key, "End") || keycode == 35) {
/*
* We interpret Home, End, PgUp and PgDn as numeric keypad
* controls regardless of whether they're the ones on the
* numeric keypad (since we can't tell). The effect of
* this should only be that the non-numeric-pad versions
* of those keys generate directions in 8-way movement
* puzzles like Cube and Inertia.
*/
keyevent = MOD_NUM_KEYPAD | '1';
} else if (!strnullcmp(key, "PageDown") || keycode==34) {
keyevent = MOD_NUM_KEYPAD | '3';
} else if (!strnullcmp(key, "Home") || keycode==36) {
keyevent = MOD_NUM_KEYPAD | '7';
} else if (!strnullcmp(key, "PageUp") || keycode==33) {
keyevent = MOD_NUM_KEYPAD | '9';
} else if (chr && chr[0] && !chr[1]) {
keyevent = chr[0] & 0xFF;
} else if (keycode >= 96 && keycode < 106) {
keyevent = MOD_NUM_KEYPAD | ('0' + keycode - 96);
} else if (keycode >= 65 && keycode <= 90) {
keyevent = keycode + (shift ? 0 : 32);
} else if (keycode >= 48 && keycode <= 57) {
keyevent = keycode;
}
if (keyevent >= 0) {
if (shift && keyevent >= 0x100)
keyevent |= MOD_SHFT;
if (ctrl) {
if (keyevent >= 0x100)
keyevent |= MOD_CTRL;
else
keyevent &= 0x1F;
}
midend_process_key(me, 0, 0, keyevent);
update_undo_redo();
}
}
/*
* Helper function called from several places to update the permalinks
* whenever a new game is created.
*/
static void update_permalinks(void)
{
char *desc, *seed;
desc = midend_get_game_id(me);
seed = midend_get_random_seed(me);
js_update_permalinks(desc, seed);
sfree(desc);
sfree(seed);
}
/*
* Callback from the midend when the game ids change, so we can update
* the permalinks.
*/
static void ids_changed(void *ignored)
{
update_permalinks();
}
/* ----------------------------------------------------------------------
* Implementation of the drawing API by calling Javascript canvas
* drawing functions. (Well, half of it; the other half is on the JS
* side.)
*/
static void js_start_draw(void *handle)
{
js_canvas_start_draw();
}
static void js_clip(void *handle, int x, int y, int w, int h)
{
js_canvas_clip_rect(x, y, w, h);
}
static void js_unclip(void *handle)
{
js_canvas_unclip();
}
static void js_draw_text(void *handle, int x, int y, int fonttype,
int fontsize, int align, int colour, char *text)
{
char fontstyle[80];
int halign;
sprintf(fontstyle, "%dpx %s", fontsize,
fonttype == FONT_FIXED ? "monospace" : "sans-serif");
if (align & ALIGN_VCENTRE)
y += js_canvas_find_font_midpoint(fontsize, fontstyle);
if (align & ALIGN_HCENTRE)
halign = 1;
else if (align & ALIGN_HRIGHT)
halign = 2;
else
halign = 0;
js_canvas_draw_text(x, y, halign, colour_strings[colour], fontstyle, text);
}
static void js_draw_rect(void *handle, int x, int y, int w, int h, int colour)
{
js_canvas_draw_rect(x, y, w, h, colour_strings[colour]);
}
static void js_draw_line(void *handle, int x1, int y1, int x2, int y2,
int colour)
{
js_canvas_draw_line(x1, y1, x2, y2, 1, colour_strings[colour]);
}
static void js_draw_thick_line(void *handle, float thickness,
float x1, float y1, float x2, float y2,
int colour)
{
js_canvas_draw_line(x1, y1, x2, y2, thickness, colour_strings[colour]);
}
static void js_draw_poly(void *handle, int *coords, int npoints,
int fillcolour, int outlinecolour)
{
js_canvas_draw_poly(coords, npoints,
fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
colour_strings[outlinecolour]);
}
static void js_draw_circle(void *handle, int cx, int cy, int radius,
int fillcolour, int outlinecolour)
{
js_canvas_draw_circle(cx, cy, radius,
fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
colour_strings[outlinecolour]);
}
struct blitter {
int id; /* allocated on the js side */
int w, h; /* easier to retain here */
};
static blitter *js_blitter_new(void *handle, int w, int h)
{
blitter *bl = snew(blitter);
bl->w = w;
bl->h = h;
bl->id = js_canvas_new_blitter(w, h);
return bl;
}
static void js_blitter_free(void *handle, blitter *bl)
{
js_canvas_free_blitter(bl->id);
sfree(bl);
}
static void trim_rect(int *x, int *y, int *w, int *h)
{
int x0, x1, y0, y1;
/*
* Reduce the size of the copied rectangle to stop it going
* outside the bounds of the canvas.
*/
/* Transform from x,y,w,h form into coordinates of all edges */
x0 = *x;
y0 = *y;
x1 = *x + *w;
y1 = *y + *h;
/* Clip each coordinate at both extremes of the canvas */
x0 = (x0 < 0 ? 0 : x0 > canvas_w ? canvas_w : x0);
x1 = (x1 < 0 ? 0 : x1 > canvas_w ? canvas_w : x1);
y0 = (y0 < 0 ? 0 : y0 > canvas_h ? canvas_h : y0);
y1 = (y1 < 0 ? 0 : y1 > canvas_h ? canvas_h : y1);
/* Transform back into x,y,w,h to return */
*x = x0;
*y = y0;
*w = x1 - x0;
*h = y1 - y0;
}
static void js_blitter_save(void *handle, blitter *bl, int x, int y)
{
int w = bl->w, h = bl->h;
trim_rect(&x, &y, &w, &h);
if (w > 0 && h > 0)
js_canvas_copy_to_blitter(bl->id, x, y, w, h);
}
static void js_blitter_load(void *handle, blitter *bl, int x, int y)
{
int w = bl->w, h = bl->h;
trim_rect(&x, &y, &w, &h);
if (w > 0 && h > 0)
js_canvas_copy_from_blitter(bl->id, x, y, w, h);
}
static void js_draw_update(void *handle, int x, int y, int w, int h)
{
trim_rect(&x, &y, &w, &h);
if (w > 0 && h > 0)
js_canvas_draw_update(x, y, w, h);
}
static void js_end_draw(void *handle)
{
js_canvas_end_draw();
}
static void js_status_bar(void *handle, char *text)
{
js_canvas_set_statusbar(text);
}
static char *js_text_fallback(void *handle, const char *const *strings,
int nstrings)
{
return dupstr(strings[0]); /* Emscripten has no trouble with UTF-8 */
}
const struct drawing_api js_drawing = {
js_draw_text,
js_draw_rect,
js_draw_line,
js_draw_poly,
js_draw_circle,
js_draw_update,
js_clip,
js_unclip,
js_start_draw,
js_end_draw,
js_status_bar,
js_blitter_new,
js_blitter_free,
js_blitter_save,
js_blitter_load,
NULL, NULL, NULL, NULL, NULL, NULL, /* {begin,end}_{doc,page,puzzle} */
NULL, NULL, /* line_width, line_dotted */
js_text_fallback,
js_draw_thick_line,
};
/* ----------------------------------------------------------------------
* Presets and game-configuration dialog support.
*/
static game_params **presets;
static int npresets;
int have_presets_dropdown;
void select_appropriate_preset(void)
{
if (have_presets_dropdown) {
int preset = midend_which_preset(me);
js_select_preset(preset < 0 ? -1 : preset);
}
}
static config_item *cfg = NULL;
static int cfg_which;
/*
* Set up a dialog box. This is pretty easy on the C side; most of the
* work is done in JS.
*/
static void cfg_start(int which)
{
char *title;
int i;
cfg = midend_get_config(me, which, &title);
cfg_which = which;
js_dialog_init(title);
sfree(title);
for (i = 0; cfg[i].type != C_END; i++) {
switch (cfg[i].type) {
case C_STRING:
js_dialog_string(i, cfg[i].name, cfg[i].sval);
break;
case C_BOOLEAN:
js_dialog_boolean(i, cfg[i].name, cfg[i].ival);
break;
case C_CHOICES:
js_dialog_choices(i, cfg[i].name, cfg[i].sval, cfg[i].ival);
break;
}
}
js_dialog_launch();
}
/*
* Callbacks from JS when the OK button is clicked, to return the
* final state of each control.
*/
void dlg_return_sval(int index, const char *val)
{
sfree(cfg[index].sval);
cfg[index].sval = dupstr(val);
}
void dlg_return_ival(int index, int val)
{
cfg[index].ival = val;
}
/*
* Called when the user clicks OK or Cancel. use_results will be TRUE
* or FALSE respectively, in those cases. We terminate the dialog box,
* unless the user selected an invalid combination of parameters.
*/
static void cfg_end(int use_results)
{
if (use_results) {
/*
* User hit OK.
*/
char *err = midend_set_config(me, cfg_which, cfg);
if (err) {
/*
* The settings were unacceptable, so leave the config box
* open for the user to adjust them and try again.
*/
js_error_box(err);
} else {
/*
* New settings are fine; start a new game and close the
* dialog.
*/
select_appropriate_preset();
midend_new_game(me);
resize();
midend_redraw(me);
free_cfg(cfg);
js_dialog_cleanup();
}
} else {
/*
* User hit Cancel. Close the dialog, but also we must still
* reselect the right element of the dropdown list.
*
* (Because: imagine you have a preset selected, and then you
* select Custom from the list, but change your mind and hit
* Esc. The Custom option will now still be selected in the
* list, whereas obviously it should show the preset you still
* _actually_ have selected. Worse still, it'll be the visible
* rather than invisible Custom option - see the comment in
* js_add_preset in emcclib.js - so you won't even be able to
* select Custom without a faffy workaround.)
*/
select_appropriate_preset();
free_cfg(cfg);
js_dialog_cleanup();
}
}
/* ----------------------------------------------------------------------
* Called from JS when a command is given to the puzzle by clicking a
* button or control of some sort.
*/
void command(int n)
{
switch (n) {
case 0: /* specific game ID */
cfg_start(CFG_DESC);
break;
case 1: /* random game seed */
cfg_start(CFG_SEED);
break;
case 2: /* game parameter dropdown changed */
{
int i = js_get_selected_preset();
if (i < 0) {
/*
* The user selected 'Custom', so launch the config
* box.
*/
if (thegame.can_configure) /* (double-check just in case) */
cfg_start(CFG_SETTINGS);
} else {
/*
* The user selected a preset, so just switch straight
* to that.
*/
assert(i < npresets);
midend_set_params(me, presets[i]);
midend_new_game(me);
resize();
midend_redraw(me);
update_undo_redo();
js_focus_canvas();
select_appropriate_preset(); /* sort out Custom/Customise */
}
}
break;
case 3: /* OK clicked in a config box */
cfg_end(TRUE);
update_undo_redo();
break;
case 4: /* Cancel clicked in a config box */
cfg_end(FALSE);
update_undo_redo();
break;
case 5: /* New Game */
midend_process_key(me, 0, 0, 'n');
update_undo_redo();
js_focus_canvas();
break;
case 6: /* Restart */
midend_restart_game(me);
update_undo_redo();
js_focus_canvas();
break;
case 7: /* Undo */
midend_process_key(me, 0, 0, 'u');
update_undo_redo();
js_focus_canvas();
break;
case 8: /* Redo */
midend_process_key(me, 0, 0, 'r');
update_undo_redo();
js_focus_canvas();
break;
case 9: /* Solve */
if (thegame.can_solve) {
char *msg = midend_solve(me);
if (msg)
js_error_box(msg);
}
update_undo_redo();
js_focus_canvas();
break;
}
}
/* ----------------------------------------------------------------------
* Setup function called at page load time. It's called main() because
* that's the most convenient thing in Emscripten, but it's not main()
* in the usual sense of bounding the program's entire execution.
* Instead, this function returns once the initial puzzle is set up
* and working, and everything thereafter happens by means of JS event
* handlers sending us callbacks.
*/
int main(int argc, char **argv)
{
char *param_err;
float *colours;
int i;
/*
* Instantiate a midend.
*/
me = midend_new(NULL, &thegame, &js_drawing, NULL);
/*
* Chuck in the HTML fragment ID if we have one (trimming the
* leading # off the front first). If that's invalid, we retain
* the error message and will display it at the end, after setting
* up a random puzzle as usual.
*/
if (argc > 1 && argv[1][0] == '#' && argv[1][1] != '\0')
param_err = midend_game_id(me, argv[1] + 1);
else
param_err = NULL;
/*
* Create either a random game or the specified one, and set the
* canvas size appropriately.
*/
midend_new_game(me);
resize();
/*
* Create a status bar, if needed.
*/
if (midend_wants_statusbar(me))
js_canvas_make_statusbar();
/*
* Set up the game-type dropdown with presets and/or the Custom
* option.
*/
npresets = midend_num_presets(me);
if (npresets == 0) {
/*
* This puzzle doesn't have selectable game types at all.
* Completely remove the drop-down list from the page.
*/
js_remove_type_dropdown();
have_presets_dropdown = FALSE;
} else {
presets = snewn(npresets, game_params *);
for (i = 0; i < npresets; i++) {
char *name;
midend_fetch_preset(me, i, &name, &presets[i]);
js_add_preset(name);
}
if (thegame.can_configure)
js_add_preset(NULL); /* the 'Custom' entry in the dropdown */
have_presets_dropdown = TRUE;
/*
* Now ensure the appropriate element of the presets menu
* starts off selected, in case it isn't the first one in the
* list (e.g. Slant).
*/
select_appropriate_preset();
}
/*
* Remove the Solve button if the game doesn't support it.
*/
if (!thegame.can_solve)
js_remove_solve_button();
/*
* Retrieve the game's colours, and convert them into #abcdef type
* hex ID strings.
*/
colours = midend_colours(me, &ncolours);
colour_strings = snewn(ncolours, char *);
for (i = 0; i < ncolours; i++) {
char col[40];
sprintf(col, "#%02x%02x%02x",
(unsigned)(0.5 + 255 * colours[i*3+0]),
(unsigned)(0.5 + 255 * colours[i*3+1]),
(unsigned)(0.5 + 255 * colours[i*3+2]));
colour_strings[i] = dupstr(col);
}
/*
* Request notification when the game ids change (e.g. if the user
* presses 'n', and also when Mines supersedes its game
* description), so that we can proactively update the permalink.
*/
midend_request_id_changes(me, ids_changed, NULL);
/*
* Draw the puzzle's initial state, and set up the permalinks and
* undo/redo greying out.
*/
midend_redraw(me);
update_permalinks();
update_undo_redo();
/*
* If we were given an erroneous game ID in argv[1], now's the
* time to put up the error box about it, after we've fully set up
* a random puzzle. Then when the user clicks 'ok', we have a
* puzzle for them.
*/
if (param_err)
js_error_box(param_err);
/*
* Done. Return to JS, and await callbacks!
*/
return 0;
}