2 * emcc.c: the C component of an Emscripten-based web/Javascript front
5 * The Javascript parts of this system live in emcclib.js and
6 * emccpre.js. It also depends on being run in the context of a web
7 * page containing an appropriate collection of bits and pieces (a
8 * canvas, some buttons and links etc), which is generated for each
9 * puzzle by the script html/jspage.pl.
13 * Further thoughts on possible enhancements:
15 * - I think it might be feasible to have these JS puzzles permit
16 * loading and saving games in disk files. Saving would be done by
17 * constructing a data: URI encapsulating the save file, and then
18 * telling the browser to visit that URI with the effect that it
19 * would naturally pop up a 'where would you like to save this'
20 * dialog box. Loading, more or less similarly, might be feasible
21 * by using the DOM File API to ask the user to select a file and
22 * permit us to see its contents.
24 * - I should think about whether these webified puzzles can support
25 * touchscreen-based tablet browsers (assuming there are any that
26 * can cope with the reasonably modern JS and run it fast enough to
29 * - think about making use of localStorage. It might be useful to
30 * let the user save games into there as an alternative to disk
31 * files - disk files are all very well for getting the save right
32 * out of your browser to (e.g.) email to me as a bug report, but
33 * for just resuming a game you were in the middle of, you'd
34 * probably rather have a nice simple 'quick save' and 'quick load'
35 * button pair. Also, that might be a useful place to store
36 * preferences, if I ever get round to writing a preferences UI.
38 * - some CSS to make the button bar and configuration dialogs a
39 * little less ugly would probably not go amiss.
41 * - this is a downright silly idea, but it does occur to me that if
42 * I were to write a PDF output driver for the Puzzles printing
43 * API, then I might be able to implement a sort of 'printing'
44 * feature in this front end, using data: URIs again. (Ask the user
45 * exactly what they want printed, then construct an appropriate
46 * PDF and embed it in a gigantic data: URI. Then they can print
47 * that using whatever they normally use to print PDFs!)
58 * Extern references to Javascript functions provided in emcclib.js.
60 extern void js_debug(const char *);
61 extern void js_error_box(const char *message);
62 extern void js_remove_type_dropdown(void);
63 extern void js_remove_solve_button(void);
64 extern void js_add_preset(const char *name);
65 extern int js_get_selected_preset(void);
66 extern void js_select_preset(int n);
67 extern void js_get_date_64(unsigned *p);
68 extern void js_update_permalinks(const char *desc, const char *seed);
69 extern void js_enable_undo_redo(int undo, int redo);
70 extern void js_activate_timer();
71 extern void js_deactivate_timer();
72 extern void js_canvas_start_draw(void);
73 extern void js_canvas_draw_update(int x, int y, int w, int h);
74 extern void js_canvas_end_draw(void);
75 extern void js_canvas_draw_rect(int x, int y, int w, int h,
77 extern void js_canvas_clip_rect(int x, int y, int w, int h);
78 extern void js_canvas_unclip(void);
79 extern void js_canvas_draw_line(float x1, float y1, float x2, float y2,
80 int width, const char *colour);
81 extern void js_canvas_draw_poly(int *points, int npoints,
82 const char *fillcolour,
83 const char *outlinecolour);
84 extern void js_canvas_draw_circle(int x, int y, int r,
85 const char *fillcolour,
86 const char *outlinecolour);
87 extern int js_canvas_find_font_midpoint(int height, const char *fontptr);
88 extern void js_canvas_draw_text(int x, int y, int halign,
89 const char *colptr, const char *fontptr,
91 extern int js_canvas_new_blitter(int w, int h);
92 extern void js_canvas_free_blitter(int id);
93 extern void js_canvas_copy_to_blitter(int id, int x, int y, int w, int h);
94 extern void js_canvas_copy_from_blitter(int id, int x, int y, int w, int h);
95 extern void js_canvas_make_statusbar(void);
96 extern void js_canvas_set_statusbar(const char *text);
97 extern void js_canvas_set_size(int w, int h);
99 extern void js_dialog_init(const char *title);
100 extern void js_dialog_string(int i, const char *title, const char *initvalue);
101 extern void js_dialog_choices(int i, const char *title, const char *choicelist,
103 extern void js_dialog_boolean(int i, const char *title, int initvalue);
104 extern void js_dialog_launch(void);
105 extern void js_dialog_cleanup(void);
106 extern void js_focus_canvas(void);
109 * Call JS to get the date, and use that to initialise our random
110 * number generator to invent the first game seed.
112 void get_random_seed(void **randseed, int *randseedsize)
114 unsigned *ret = snewn(2, unsigned);
117 *randseedsize = 2*sizeof(unsigned);
121 * Fatal error, called in cases of complete despair such as when
122 * malloc() has returned NULL.
124 void fatal(char *fmt, ...)
129 strcpy(buf, "puzzle fatal error: ");
132 vsnprintf(buf+strlen(buf), sizeof(buf)-strlen(buf), fmt, ap);
138 void debug_printf(char *fmt, ...)
143 vsnprintf(buf, sizeof(buf), fmt, ap);
149 * Helper function that makes it easy to test strings that might be
152 int strnullcmp(const char *a, const char *b)
154 if (a == NULL || b == NULL)
155 return a != NULL ? +1 : b != NULL ? -1 : 0;
160 * HTMLish names for the colours allocated by the puzzle.
162 char **colour_strings;
166 * The global midend object.
170 /* ----------------------------------------------------------------------
173 int timer_active = FALSE;
174 void deactivate_timer(frontend *fe)
176 js_deactivate_timer();
177 timer_active = FALSE;
179 void activate_timer(frontend *fe)
186 void timer_callback(double tplus)
189 midend_timer(me, tplus);
192 /* ----------------------------------------------------------------------
193 * Helper functions to resize the canvas, and variables to remember
194 * its size for other functions (e.g. trimming blitter rectangles).
196 static int canvas_w, canvas_h;
198 /* Called when we resize as a result of changing puzzle settings */
199 static void resize(void)
203 midend_size(me, &w, &h, FALSE);
204 js_canvas_set_size(w, h);
209 /* Called from JS when the user uses the resize handle */
210 void resize_puzzle(int w, int h)
212 midend_size(me, &w, &h, TRUE);
213 if (canvas_w != w || canvas_h != h) {
214 js_canvas_set_size(w, h);
217 midend_force_redraw(me);
221 /* Called from JS when the user uses the restore button */
222 void restore_puzzle_size(int w, int h)
224 midend_reset_tilesize(me);
226 midend_force_redraw(me);
230 * HTML doesn't give us a default frontend colour of its own, so we
231 * just make up a lightish grey ourselves.
233 void frontend_default_colour(frontend *fe, float *output)
235 output[0] = output[1] = output[2] = 0.9F;
239 * Helper function called from all over the place to ensure the undo
240 * and redo buttons get properly enabled and disabled after every move
241 * or undo or new-game event.
243 static void update_undo_redo(void)
245 js_enable_undo_redo(midend_can_undo(me), midend_can_redo(me));
249 * Mouse event handlers called from JS.
251 void mousedown(int x, int y, int button)
253 button = (button == 0 ? LEFT_BUTTON :
254 button == 1 ? MIDDLE_BUTTON : RIGHT_BUTTON);
255 midend_process_key(me, x, y, button);
259 void mouseup(int x, int y, int button)
261 button = (button == 0 ? LEFT_RELEASE :
262 button == 1 ? MIDDLE_RELEASE : RIGHT_RELEASE);
263 midend_process_key(me, x, y, button);
267 void mousemove(int x, int y, int buttons)
269 int button = (buttons & 2 ? MIDDLE_DRAG :
270 buttons & 4 ? RIGHT_DRAG : LEFT_DRAG);
271 midend_process_key(me, x, y, button);
276 * Keyboard handler called from JS.
278 void key(int keycode, int charcode, const char *key, const char *chr,
283 if (!strnullcmp(key, "Backspace") || !strnullcmp(key, "Del") ||
284 keycode == 8 || keycode == 46) {
285 keyevent = 127; /* Backspace / Delete */
286 } else if (!strnullcmp(key, "Enter") || keycode == 13) {
287 keyevent = 13; /* return */
288 } else if (!strnullcmp(key, "Left") || keycode == 37) {
289 keyevent = CURSOR_LEFT;
290 } else if (!strnullcmp(key, "Up") || keycode == 38) {
291 keyevent = CURSOR_UP;
292 } else if (!strnullcmp(key, "Right") || keycode == 39) {
293 keyevent = CURSOR_RIGHT;
294 } else if (!strnullcmp(key, "Down") || keycode == 40) {
295 keyevent = CURSOR_DOWN;
296 } else if (!strnullcmp(key, "End") || keycode == 35) {
298 * We interpret Home, End, PgUp and PgDn as numeric keypad
299 * controls regardless of whether they're the ones on the
300 * numeric keypad (since we can't tell). The effect of
301 * this should only be that the non-numeric-pad versions
302 * of those keys generate directions in 8-way movement
303 * puzzles like Cube and Inertia.
305 keyevent = MOD_NUM_KEYPAD | '1';
306 } else if (!strnullcmp(key, "PageDown") || keycode==34) {
307 keyevent = MOD_NUM_KEYPAD | '3';
308 } else if (!strnullcmp(key, "Home") || keycode==36) {
309 keyevent = MOD_NUM_KEYPAD | '7';
310 } else if (!strnullcmp(key, "PageUp") || keycode==33) {
311 keyevent = MOD_NUM_KEYPAD | '9';
312 } else if (chr && chr[0] && !chr[1]) {
313 keyevent = chr[0] & 0xFF;
314 } else if (keycode >= 96 && keycode < 106) {
315 keyevent = MOD_NUM_KEYPAD | ('0' + keycode - 96);
316 } else if (keycode >= 65 && keycode <= 90) {
317 keyevent = keycode + (shift ? 0 : 32);
318 } else if (keycode >= 48 && keycode <= 57) {
320 } else if (keycode == 32) { /* space / CURSOR_SELECT2 */
325 if (shift && keyevent >= 0x100)
326 keyevent |= MOD_SHFT;
329 if (keyevent >= 0x100)
330 keyevent |= MOD_CTRL;
335 midend_process_key(me, 0, 0, keyevent);
341 * Helper function called from several places to update the permalinks
342 * whenever a new game is created.
344 static void update_permalinks(void)
347 desc = midend_get_game_id(me);
348 seed = midend_get_random_seed(me);
349 js_update_permalinks(desc, seed);
355 * Callback from the midend when the game ids change, so we can update
358 static void ids_changed(void *ignored)
363 /* ----------------------------------------------------------------------
364 * Implementation of the drawing API by calling Javascript canvas
365 * drawing functions. (Well, half of it; the other half is on the JS
368 static void js_start_draw(void *handle)
370 js_canvas_start_draw();
373 static void js_clip(void *handle, int x, int y, int w, int h)
375 js_canvas_clip_rect(x, y, w, h);
378 static void js_unclip(void *handle)
383 static void js_draw_text(void *handle, int x, int y, int fonttype,
384 int fontsize, int align, int colour, char *text)
389 sprintf(fontstyle, "%dpx %s", fontsize,
390 fonttype == FONT_FIXED ? "monospace" : "sans-serif");
392 if (align & ALIGN_VCENTRE)
393 y += js_canvas_find_font_midpoint(fontsize, fontstyle);
395 if (align & ALIGN_HCENTRE)
397 else if (align & ALIGN_HRIGHT)
402 js_canvas_draw_text(x, y, halign, colour_strings[colour], fontstyle, text);
405 static void js_draw_rect(void *handle, int x, int y, int w, int h, int colour)
407 js_canvas_draw_rect(x, y, w, h, colour_strings[colour]);
410 static void js_draw_line(void *handle, int x1, int y1, int x2, int y2,
413 js_canvas_draw_line(x1, y1, x2, y2, 1, colour_strings[colour]);
416 static void js_draw_thick_line(void *handle, float thickness,
417 float x1, float y1, float x2, float y2,
420 js_canvas_draw_line(x1, y1, x2, y2, thickness, colour_strings[colour]);
423 static void js_draw_poly(void *handle, int *coords, int npoints,
424 int fillcolour, int outlinecolour)
426 js_canvas_draw_poly(coords, npoints,
427 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
428 colour_strings[outlinecolour]);
431 static void js_draw_circle(void *handle, int cx, int cy, int radius,
432 int fillcolour, int outlinecolour)
434 js_canvas_draw_circle(cx, cy, radius,
435 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
436 colour_strings[outlinecolour]);
440 int id; /* allocated on the js side */
441 int w, h; /* easier to retain here */
444 static blitter *js_blitter_new(void *handle, int w, int h)
446 blitter *bl = snew(blitter);
449 bl->id = js_canvas_new_blitter(w, h);
453 static void js_blitter_free(void *handle, blitter *bl)
455 js_canvas_free_blitter(bl->id);
459 static void trim_rect(int *x, int *y, int *w, int *h)
464 * Reduce the size of the copied rectangle to stop it going
465 * outside the bounds of the canvas.
468 /* Transform from x,y,w,h form into coordinates of all edges */
474 /* Clip each coordinate at both extremes of the canvas */
475 x0 = (x0 < 0 ? 0 : x0 > canvas_w ? canvas_w : x0);
476 x1 = (x1 < 0 ? 0 : x1 > canvas_w ? canvas_w : x1);
477 y0 = (y0 < 0 ? 0 : y0 > canvas_h ? canvas_h : y0);
478 y1 = (y1 < 0 ? 0 : y1 > canvas_h ? canvas_h : y1);
480 /* Transform back into x,y,w,h to return */
487 static void js_blitter_save(void *handle, blitter *bl, int x, int y)
489 int w = bl->w, h = bl->h;
490 trim_rect(&x, &y, &w, &h);
492 js_canvas_copy_to_blitter(bl->id, x, y, w, h);
495 static void js_blitter_load(void *handle, blitter *bl, int x, int y)
497 int w = bl->w, h = bl->h;
498 trim_rect(&x, &y, &w, &h);
500 js_canvas_copy_from_blitter(bl->id, x, y, w, h);
503 static void js_draw_update(void *handle, int x, int y, int w, int h)
505 trim_rect(&x, &y, &w, &h);
507 js_canvas_draw_update(x, y, w, h);
510 static void js_end_draw(void *handle)
512 js_canvas_end_draw();
515 static void js_status_bar(void *handle, char *text)
517 js_canvas_set_statusbar(text);
520 static char *js_text_fallback(void *handle, const char *const *strings,
523 return dupstr(strings[0]); /* Emscripten has no trouble with UTF-8 */
526 const struct drawing_api js_drawing = {
542 NULL, NULL, NULL, NULL, NULL, NULL, /* {begin,end}_{doc,page,puzzle} */
543 NULL, NULL, /* line_width, line_dotted */
548 /* ----------------------------------------------------------------------
549 * Presets and game-configuration dialog support.
551 static game_params **presets;
553 int have_presets_dropdown;
555 void select_appropriate_preset(void)
557 if (have_presets_dropdown) {
558 int preset = midend_which_preset(me);
559 js_select_preset(preset < 0 ? -1 : preset);
563 static config_item *cfg = NULL;
564 static int cfg_which;
567 * Set up a dialog box. This is pretty easy on the C side; most of the
568 * work is done in JS.
570 static void cfg_start(int which)
575 cfg = midend_get_config(me, which, &title);
578 js_dialog_init(title);
581 for (i = 0; cfg[i].type != C_END; i++) {
582 switch (cfg[i].type) {
584 js_dialog_string(i, cfg[i].name, cfg[i].sval);
587 js_dialog_boolean(i, cfg[i].name, cfg[i].ival);
590 js_dialog_choices(i, cfg[i].name, cfg[i].sval, cfg[i].ival);
599 * Callbacks from JS when the OK button is clicked, to return the
600 * final state of each control.
602 void dlg_return_sval(int index, const char *val)
604 sfree(cfg[index].sval);
605 cfg[index].sval = dupstr(val);
607 void dlg_return_ival(int index, int val)
609 cfg[index].ival = val;
613 * Called when the user clicks OK or Cancel. use_results will be TRUE
614 * or FALSE respectively, in those cases. We terminate the dialog box,
615 * unless the user selected an invalid combination of parameters.
617 static void cfg_end(int use_results)
623 char *err = midend_set_config(me, cfg_which, cfg);
627 * The settings were unacceptable, so leave the config box
628 * open for the user to adjust them and try again.
633 * New settings are fine; start a new game and close the
636 select_appropriate_preset();
645 * User hit Cancel. Close the dialog, but also we must still
646 * reselect the right element of the dropdown list.
648 * (Because: imagine you have a preset selected, and then you
649 * select Custom from the list, but change your mind and hit
650 * Esc. The Custom option will now still be selected in the
651 * list, whereas obviously it should show the preset you still
652 * _actually_ have selected. Worse still, it'll be the visible
653 * rather than invisible Custom option - see the comment in
654 * js_add_preset in emcclib.js - so you won't even be able to
655 * select Custom without a faffy workaround.)
657 select_appropriate_preset();
664 /* ----------------------------------------------------------------------
665 * Called from JS when a command is given to the puzzle by clicking a
666 * button or control of some sort.
671 case 0: /* specific game ID */
674 case 1: /* random game seed */
677 case 2: /* game parameter dropdown changed */
679 int i = js_get_selected_preset();
682 * The user selected 'Custom', so launch the config
685 if (thegame.can_configure) /* (double-check just in case) */
686 cfg_start(CFG_SETTINGS);
689 * The user selected a preset, so just switch straight
692 assert(i < npresets);
693 midend_set_params(me, presets[i]);
699 select_appropriate_preset();
703 case 3: /* OK clicked in a config box */
707 case 4: /* Cancel clicked in a config box */
711 case 5: /* New Game */
712 midend_process_key(me, 0, 0, 'n');
716 case 6: /* Restart */
717 midend_restart_game(me);
722 midend_process_key(me, 0, 0, 'u');
727 midend_process_key(me, 0, 0, 'r');
732 if (thegame.can_solve) {
733 char *msg = midend_solve(me);
743 /* ----------------------------------------------------------------------
744 * Setup function called at page load time. It's called main() because
745 * that's the most convenient thing in Emscripten, but it's not main()
746 * in the usual sense of bounding the program's entire execution.
747 * Instead, this function returns once the initial puzzle is set up
748 * and working, and everything thereafter happens by means of JS event
749 * handlers sending us callbacks.
751 int main(int argc, char **argv)
758 * Instantiate a midend.
760 me = midend_new(NULL, &thegame, &js_drawing, NULL);
763 * Chuck in the HTML fragment ID if we have one (trimming the
764 * leading # off the front first). If that's invalid, we retain
765 * the error message and will display it at the end, after setting
766 * up a random puzzle as usual.
768 if (argc > 1 && argv[1][0] == '#' && argv[1][1] != '\0')
769 param_err = midend_game_id(me, argv[1] + 1);
774 * Create either a random game or the specified one, and set the
775 * canvas size appropriately.
781 * Create a status bar, if needed.
783 if (midend_wants_statusbar(me))
784 js_canvas_make_statusbar();
787 * Set up the game-type dropdown with presets and/or the Custom
790 npresets = midend_num_presets(me);
793 * This puzzle doesn't have selectable game types at all.
794 * Completely remove the drop-down list from the page.
796 js_remove_type_dropdown();
797 have_presets_dropdown = FALSE;
799 presets = snewn(npresets, game_params *);
800 for (i = 0; i < npresets; i++) {
802 midend_fetch_preset(me, i, &name, &presets[i]);
805 if (thegame.can_configure)
806 js_add_preset(NULL); /* the 'Custom' entry in the dropdown */
808 have_presets_dropdown = TRUE;
811 * Now ensure the appropriate element of the presets menu
812 * starts off selected, in case it isn't the first one in the
815 select_appropriate_preset();
819 * Remove the Solve button if the game doesn't support it.
821 if (!thegame.can_solve)
822 js_remove_solve_button();
825 * Retrieve the game's colours, and convert them into #abcdef type
828 colours = midend_colours(me, &ncolours);
829 colour_strings = snewn(ncolours, char *);
830 for (i = 0; i < ncolours; i++) {
832 sprintf(col, "#%02x%02x%02x",
833 (unsigned)(0.5 + 255 * colours[i*3+0]),
834 (unsigned)(0.5 + 255 * colours[i*3+1]),
835 (unsigned)(0.5 + 255 * colours[i*3+2]));
836 colour_strings[i] = dupstr(col);
840 * Request notification when the game ids change (e.g. if the user
841 * presses 'n', and also when Mines supersedes its game
842 * description), so that we can proactively update the permalink.
844 midend_request_id_changes(me, ids_changed, NULL);
847 * Draw the puzzle's initial state, and set up the permalinks and
848 * undo/redo greying out.
855 * If we were given an erroneous game ID in argv[1], now's the
856 * time to put up the error box about it, after we've fully set up
857 * a random puzzle. Then when the user clicks 'ok', we have a
861 js_error_box(param_err);
864 * Done. Return to JS, and await callbacks!