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!)
56 * Extern references to Javascript functions provided in emcclib.js.
58 extern void js_debug(const char *);
59 extern void js_error_box(const char *message);
60 extern void js_remove_type_dropdown(void);
61 extern void js_remove_solve_button(void);
62 extern void js_add_preset(const char *name);
63 extern int js_get_selected_preset(void);
64 extern void js_select_preset(int n);
65 extern void js_get_date_64(unsigned *p);
66 extern void js_update_permalinks(const char *desc, const char *seed);
67 extern void js_enable_undo_redo(int undo, int redo);
68 extern void js_activate_timer();
69 extern void js_deactivate_timer();
70 extern void js_canvas_start_draw(void);
71 extern void js_canvas_draw_update(int x, int y, int w, int h);
72 extern void js_canvas_end_draw(void);
73 extern void js_canvas_draw_rect(int x, int y, int w, int h,
75 extern void js_canvas_clip_rect(int x, int y, int w, int h);
76 extern void js_canvas_unclip(void);
77 extern void js_canvas_draw_line(float x1, float y1, float x2, float y2,
78 int width, const char *colour);
79 extern void js_canvas_draw_poly(int *points, int npoints,
80 const char *fillcolour,
81 const char *outlinecolour);
82 extern void js_canvas_draw_circle(int x, int y, int r,
83 const char *fillcolour,
84 const char *outlinecolour);
85 extern int js_canvas_find_font_midpoint(int height, const char *fontptr);
86 extern void js_canvas_draw_text(int x, int y, int halign,
87 const char *colptr, const char *fontptr,
89 extern int js_canvas_new_blitter(int w, int h);
90 extern void js_canvas_free_blitter(int id);
91 extern void js_canvas_copy_to_blitter(int id, int x, int y, int w, int h);
92 extern void js_canvas_copy_from_blitter(int id, int x, int y, int w, int h);
93 extern void js_canvas_make_statusbar(void);
94 extern void js_canvas_set_statusbar(const char *text);
95 extern void js_canvas_set_size(int w, int h);
97 extern void js_dialog_init(const char *title);
98 extern void js_dialog_string(int i, const char *title, const char *initvalue);
99 extern void js_dialog_choices(int i, const char *title, const char *choicelist,
101 extern void js_dialog_boolean(int i, const char *title, int initvalue);
102 extern void js_dialog_launch(void);
103 extern void js_dialog_cleanup(void);
104 extern void js_focus_canvas(void);
107 * Call JS to get the date, and use that to initialise our random
108 * number generator to invent the first game seed.
110 void get_random_seed(void **randseed, int *randseedsize)
112 unsigned *ret = snewn(2, unsigned);
115 *randseedsize = 2*sizeof(unsigned);
119 * Fatal error, called in cases of complete despair such as when
120 * malloc() has returned NULL.
122 void fatal(char *fmt, ...)
127 strcpy(buf, "puzzle fatal error: ");
130 vsnprintf(buf+strlen(buf), sizeof(buf)-strlen(buf), fmt, ap);
136 void debug_printf(char *fmt, ...)
141 vsnprintf(buf, sizeof(buf), fmt, ap);
147 * Helper function that makes it easy to test strings that might be
150 int strnullcmp(const char *a, const char *b)
152 if (a == NULL || b == NULL)
153 return a != NULL ? +1 : b != NULL ? -1 : 0;
158 * HTMLish names for the colours allocated by the puzzle.
160 char **colour_strings;
164 * The global midend object.
168 /* ----------------------------------------------------------------------
171 int timer_active = FALSE;
172 void deactivate_timer(frontend *fe)
174 js_deactivate_timer();
175 timer_active = FALSE;
177 void activate_timer(frontend *fe)
184 void timer_callback(double tplus)
187 midend_timer(me, tplus);
190 /* ----------------------------------------------------------------------
191 * Helper functions to resize the canvas, and variables to remember
192 * its size for other functions (e.g. trimming blitter rectangles).
194 static int canvas_w, canvas_h;
196 /* Called when we resize as a result of changing puzzle settings */
197 static void resize(void)
201 midend_size(me, &w, &h, FALSE);
202 js_canvas_set_size(w, h);
207 /* Called from JS when the user uses the resize handle */
208 void resize_puzzle(int w, int h)
210 midend_size(me, &w, &h, TRUE);
211 if (canvas_w != w || canvas_h != h) {
212 js_canvas_set_size(w, h);
215 midend_force_redraw(me);
219 /* Called from JS when the user uses the restore button */
220 void restore_puzzle_size(int w, int h)
222 midend_reset_tilesize(me);
224 midend_force_redraw(me);
228 * HTML doesn't give us a default frontend colour of its own, so we
229 * just make up a lightish grey ourselves.
231 void frontend_default_colour(frontend *fe, float *output)
233 output[0] = output[1] = output[2] = 0.9F;
237 * Helper function called from all over the place to ensure the undo
238 * and redo buttons get properly enabled and disabled after every move
239 * or undo or new-game event.
241 static void update_undo_redo(void)
243 js_enable_undo_redo(midend_can_undo(me), midend_can_redo(me));
247 * Mouse event handlers called from JS.
249 void mousedown(int x, int y, int button)
251 button = (button == 0 ? LEFT_BUTTON :
252 button == 1 ? MIDDLE_BUTTON : RIGHT_BUTTON);
253 midend_process_key(me, x, y, button);
257 void mouseup(int x, int y, int button)
259 button = (button == 0 ? LEFT_RELEASE :
260 button == 1 ? MIDDLE_RELEASE : RIGHT_RELEASE);
261 midend_process_key(me, x, y, button);
265 void mousemove(int x, int y, int buttons)
267 int button = (buttons & 2 ? MIDDLE_DRAG :
268 buttons & 4 ? RIGHT_DRAG : LEFT_DRAG);
269 midend_process_key(me, x, y, button);
274 * Keyboard handler called from JS.
276 void key(int keycode, int charcode, const char *key, const char *chr,
281 if (!strnullcmp(key, "Backspace") || !strnullcmp(key, "Del") ||
282 keycode == 8 || keycode == 46) {
283 keyevent = 127; /* Backspace / Delete */
284 } else if (!strnullcmp(key, "Enter") || keycode == 13) {
285 keyevent = 13; /* return */
286 } else if (!strnullcmp(key, "Left") || keycode == 37) {
287 keyevent = CURSOR_LEFT;
288 } else if (!strnullcmp(key, "Up") || keycode == 38) {
289 keyevent = CURSOR_UP;
290 } else if (!strnullcmp(key, "Right") || keycode == 39) {
291 keyevent = CURSOR_RIGHT;
292 } else if (!strnullcmp(key, "Down") || keycode == 40) {
293 keyevent = CURSOR_DOWN;
294 } else if (!strnullcmp(key, "End") || keycode == 35) {
296 * We interpret Home, End, PgUp and PgDn as numeric keypad
297 * controls regardless of whether they're the ones on the
298 * numeric keypad (since we can't tell). The effect of
299 * this should only be that the non-numeric-pad versions
300 * of those keys generate directions in 8-way movement
301 * puzzles like Cube and Inertia.
303 keyevent = MOD_NUM_KEYPAD | '1';
304 } else if (!strnullcmp(key, "PageDown") || keycode==34) {
305 keyevent = MOD_NUM_KEYPAD | '3';
306 } else if (!strnullcmp(key, "Home") || keycode==36) {
307 keyevent = MOD_NUM_KEYPAD | '7';
308 } else if (!strnullcmp(key, "PageUp") || keycode==33) {
309 keyevent = MOD_NUM_KEYPAD | '9';
310 } else if (chr && chr[0] && !chr[1]) {
311 keyevent = chr[0] & 0xFF;
312 } else if (keycode >= 96 && keycode < 106) {
313 keyevent = MOD_NUM_KEYPAD | ('0' + keycode - 96);
314 } else if (keycode >= 65 && keycode <= 90) {
315 keyevent = keycode + (shift ? 0 : 32);
316 } else if (keycode >= 48 && keycode <= 57) {
321 if (shift && keyevent >= 0x100)
322 keyevent |= MOD_SHFT;
325 if (keyevent >= 0x100)
326 keyevent |= MOD_CTRL;
331 midend_process_key(me, 0, 0, keyevent);
337 * Helper function called from several places to update the permalinks
338 * whenever a new game is created.
340 static void update_permalinks(void)
343 desc = midend_get_game_id(me);
344 seed = midend_get_random_seed(me);
345 js_update_permalinks(desc, seed);
351 * Callback from the midend when the game ids change, so we can update
354 static void ids_changed(void *ignored)
359 /* ----------------------------------------------------------------------
360 * Implementation of the drawing API by calling Javascript canvas
361 * drawing functions. (Well, half of it; the other half is on the JS
364 static void js_start_draw(void *handle)
366 js_canvas_start_draw();
369 static void js_clip(void *handle, int x, int y, int w, int h)
371 js_canvas_clip_rect(x, y, w, h);
374 static void js_unclip(void *handle)
379 static void js_draw_text(void *handle, int x, int y, int fonttype,
380 int fontsize, int align, int colour, char *text)
385 sprintf(fontstyle, "%dpx %s", fontsize,
386 fonttype == FONT_FIXED ? "monospace" : "sans-serif");
388 if (align & ALIGN_VCENTRE)
389 y += js_canvas_find_font_midpoint(fontsize, fontstyle);
391 if (align & ALIGN_HCENTRE)
393 else if (align & ALIGN_HRIGHT)
398 js_canvas_draw_text(x, y, halign, colour_strings[colour], fontstyle, text);
401 static void js_draw_rect(void *handle, int x, int y, int w, int h, int colour)
403 js_canvas_draw_rect(x, y, w, h, colour_strings[colour]);
406 static void js_draw_line(void *handle, int x1, int y1, int x2, int y2,
409 js_canvas_draw_line(x1, y1, x2, y2, 1, colour_strings[colour]);
412 static void js_draw_thick_line(void *handle, float thickness,
413 float x1, float y1, float x2, float y2,
416 js_canvas_draw_line(x1, y1, x2, y2, thickness, colour_strings[colour]);
419 static void js_draw_poly(void *handle, int *coords, int npoints,
420 int fillcolour, int outlinecolour)
422 js_canvas_draw_poly(coords, npoints,
423 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
424 colour_strings[outlinecolour]);
427 static void js_draw_circle(void *handle, int cx, int cy, int radius,
428 int fillcolour, int outlinecolour)
430 js_canvas_draw_circle(cx, cy, radius,
431 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
432 colour_strings[outlinecolour]);
436 int id; /* allocated on the js side */
437 int w, h; /* easier to retain here */
440 static blitter *js_blitter_new(void *handle, int w, int h)
442 blitter *bl = snew(blitter);
445 bl->id = js_canvas_new_blitter(w, h);
449 static void js_blitter_free(void *handle, blitter *bl)
451 js_canvas_free_blitter(bl->id);
455 static void trim_rect(int *x, int *y, int *w, int *h)
460 * Reduce the size of the copied rectangle to stop it going
461 * outside the bounds of the canvas.
464 /* Transform from x,y,w,h form into coordinates of all edges */
470 /* Clip each coordinate at both extremes of the canvas */
471 x0 = (x0 < 0 ? 0 : x0 > canvas_w ? canvas_w : x0);
472 x1 = (x1 < 0 ? 0 : x1 > canvas_w ? canvas_w : x1);
473 y0 = (y0 < 0 ? 0 : y0 > canvas_h ? canvas_h : y0);
474 y1 = (y1 < 0 ? 0 : y1 > canvas_h ? canvas_h : y1);
476 /* Transform back into x,y,w,h to return */
483 static void js_blitter_save(void *handle, blitter *bl, int x, int y)
485 int w = bl->w, h = bl->h;
486 trim_rect(&x, &y, &w, &h);
488 js_canvas_copy_to_blitter(bl->id, x, y, w, h);
491 static void js_blitter_load(void *handle, blitter *bl, int x, int y)
493 int w = bl->w, h = bl->h;
494 trim_rect(&x, &y, &w, &h);
496 js_canvas_copy_from_blitter(bl->id, x, y, w, h);
499 static void js_draw_update(void *handle, int x, int y, int w, int h)
501 trim_rect(&x, &y, &w, &h);
503 js_canvas_draw_update(x, y, w, h);
506 static void js_end_draw(void *handle)
508 js_canvas_end_draw();
511 static void js_status_bar(void *handle, char *text)
513 js_canvas_set_statusbar(text);
516 static char *js_text_fallback(void *handle, const char *const *strings,
519 return dupstr(strings[0]); /* Emscripten has no trouble with UTF-8 */
522 const struct drawing_api js_drawing = {
538 NULL, NULL, NULL, NULL, NULL, NULL, /* {begin,end}_{doc,page,puzzle} */
539 NULL, NULL, /* line_width, line_dotted */
544 /* ----------------------------------------------------------------------
545 * Presets and game-configuration dialog support.
547 static game_params **presets;
549 int have_presets_dropdown;
551 void select_appropriate_preset(void)
553 if (have_presets_dropdown) {
554 int preset = midend_which_preset(me);
555 js_select_preset(preset < 0 ? -1 : preset);
559 static config_item *cfg = NULL;
560 static int cfg_which;
563 * Set up a dialog box. This is pretty easy on the C side; most of the
564 * work is done in JS.
566 static void cfg_start(int which)
571 cfg = midend_get_config(me, which, &title);
574 js_dialog_init(title);
577 for (i = 0; cfg[i].type != C_END; i++) {
578 switch (cfg[i].type) {
580 js_dialog_string(i, cfg[i].name, cfg[i].sval);
583 js_dialog_boolean(i, cfg[i].name, cfg[i].ival);
586 js_dialog_choices(i, cfg[i].name, cfg[i].sval, cfg[i].ival);
595 * Callbacks from JS when the OK button is clicked, to return the
596 * final state of each control.
598 void dlg_return_sval(int index, const char *val)
600 sfree(cfg[index].sval);
601 cfg[index].sval = dupstr(val);
603 void dlg_return_ival(int index, int val)
605 cfg[index].ival = val;
609 * Called when the user clicks OK or Cancel. use_results will be TRUE
610 * or FALSE respectively, in those cases. We terminate the dialog box,
611 * unless the user selected an invalid combination of parameters.
613 static void cfg_end(int use_results)
619 char *err = midend_set_config(me, cfg_which, cfg);
623 * The settings were unacceptable, so leave the config box
624 * open for the user to adjust them and try again.
629 * New settings are fine; start a new game and close the
632 select_appropriate_preset();
641 * User hit Cancel. Close the dialog, but also we must still
642 * reselect the right element of the dropdown list.
644 * (Because: imagine you have a preset selected, and then you
645 * select Custom from the list, but change your mind and hit
646 * Esc. The Custom option will now still be selected in the
647 * list, whereas obviously it should show the preset you still
648 * _actually_ have selected. Worse still, it'll be the visible
649 * rather than invisible Custom option - see the comment in
650 * js_add_preset in emcclib.js - so you won't even be able to
651 * select Custom without a faffy workaround.)
653 select_appropriate_preset();
660 /* ----------------------------------------------------------------------
661 * Called from JS when a command is given to the puzzle by clicking a
662 * button or control of some sort.
667 case 0: /* specific game ID */
670 case 1: /* random game seed */
673 case 2: /* game parameter dropdown changed */
675 int i = js_get_selected_preset();
678 * The user selected 'Custom', so launch the config
681 if (thegame.can_configure) /* (double-check just in case) */
682 cfg_start(CFG_SETTINGS);
685 * The user selected a preset, so just switch straight
688 assert(i < npresets);
689 midend_set_params(me, presets[i]);
695 select_appropriate_preset(); /* sort out Custom/Customise */
699 case 3: /* OK clicked in a config box */
703 case 4: /* Cancel clicked in a config box */
707 case 5: /* New Game */
708 midend_process_key(me, 0, 0, 'n');
712 case 6: /* Restart */
713 midend_restart_game(me);
718 midend_process_key(me, 0, 0, 'u');
723 midend_process_key(me, 0, 0, 'r');
728 if (thegame.can_solve) {
729 char *msg = midend_solve(me);
739 /* ----------------------------------------------------------------------
740 * Setup function called at page load time. It's called main() because
741 * that's the most convenient thing in Emscripten, but it's not main()
742 * in the usual sense of bounding the program's entire execution.
743 * Instead, this function returns once the initial puzzle is set up
744 * and working, and everything thereafter happens by means of JS event
745 * handlers sending us callbacks.
747 int main(int argc, char **argv)
754 * Instantiate a midend.
756 me = midend_new(NULL, &thegame, &js_drawing, NULL);
759 * Chuck in the HTML fragment ID if we have one (trimming the
760 * leading # off the front first). If that's invalid, we retain
761 * the error message and will display it at the end, after setting
762 * up a random puzzle as usual.
764 if (argc > 1 && argv[1][0] == '#' && argv[1][1] != '\0')
765 param_err = midend_game_id(me, argv[1] + 1);
770 * Create either a random game or the specified one, and set the
771 * canvas size appropriately.
777 * Create a status bar, if needed.
779 if (midend_wants_statusbar(me))
780 js_canvas_make_statusbar();
783 * Set up the game-type dropdown with presets and/or the Custom
786 npresets = midend_num_presets(me);
789 * This puzzle doesn't have selectable game types at all.
790 * Completely remove the drop-down list from the page.
792 js_remove_type_dropdown();
793 have_presets_dropdown = FALSE;
797 presets = snewn(npresets, game_params *);
798 for (i = 0; i < npresets; i++) {
800 midend_fetch_preset(me, i, &name, &presets[i]);
803 if (thegame.can_configure)
804 js_add_preset(NULL); /* the 'Custom' entry in the dropdown */
806 have_presets_dropdown = TRUE;
809 * Now ensure the appropriate element of the presets menu
810 * starts off selected, in case it isn't the first one in the
813 select_appropriate_preset();
817 * Remove the Solve button if the game doesn't support it.
819 if (!thegame.can_solve)
820 js_remove_solve_button();
823 * Retrieve the game's colours, and convert them into #abcdef type
826 colours = midend_colours(me, &ncolours);
827 colour_strings = snewn(ncolours, char *);
828 for (i = 0; i < ncolours; i++) {
830 sprintf(col, "#%02x%02x%02x",
831 (unsigned)(0.5 + 255 * colours[i*3+0]),
832 (unsigned)(0.5 + 255 * colours[i*3+1]),
833 (unsigned)(0.5 + 255 * colours[i*3+2]));
834 colour_strings[i] = dupstr(col);
838 * Request notification when the game ids change (e.g. if the user
839 * presses 'n', and also when Mines supersedes its game
840 * description), so that we can proactively update the permalink.
842 midend_request_id_changes(me, ids_changed, NULL);
845 * Draw the puzzle's initial state, and set up the permalinks and
846 * undo/redo greying out.
853 * If we were given an erroneous game ID in argv[1], now's the
854 * time to put up the error box about it, after we've fully set up
855 * a random puzzle. Then when the user clicks 'ok', we have a
859 js_error_box(param_err);
862 * Done. Return to JS, and await callbacks!