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 * - it ought to be possible to make the puzzle canvases resizable,
25 * by superimposing some kind of draggable resize handle. Also I
26 * quite like the idea of having a few buttons for standard sizes:
27 * reset to default size, maximise to the browser window dimensions
28 * (if we can find those out), and perhaps even go full-screen.
30 * - I should think about whether these webified puzzles can support
31 * touchscreen-based tablet browsers (assuming there are any that
32 * can cope with the reasonably modern JS and run it fast enough to
35 * - think about making use of localStorage. It might be useful to
36 * let the user save games into there as an alternative to disk
37 * files - disk files are all very well for getting the save right
38 * out of your browser to (e.g.) email to me as a bug report, but
39 * for just resuming a game you were in the middle of, you'd
40 * probably rather have a nice simple 'quick save' and 'quick load'
41 * button pair. Also, that might be a useful place to store
42 * preferences, if I ever get round to writing a preferences UI.
44 * - some CSS to make the button bar and configuration dialogs a
45 * little less ugly would probably not go amiss.
47 * - this is a downright silly idea, but it does occur to me that if
48 * I were to write a PDF output driver for the Puzzles printing
49 * API, then I might be able to implement a sort of 'printing'
50 * feature in this front end, using data: URIs again. (Ask the user
51 * exactly what they want printed, then construct an appropriate
52 * PDF and embed it in a gigantic data: URI. Then they can print
53 * that using whatever they normally use to print PDFs!)
61 * Extern references to Javascript functions provided in emcclib.js.
63 extern void js_debug(const char *);
64 extern void js_error_box(const char *message);
65 extern void js_remove_type_dropdown(void);
66 extern void js_remove_solve_button(void);
67 extern void js_add_preset(const char *name);
68 extern int js_get_selected_preset(void);
69 extern void js_select_preset(int n);
70 extern void js_get_date_64(unsigned *p);
71 extern void js_update_permalinks(const char *desc, const char *seed);
72 extern void js_enable_undo_redo(int undo, int redo);
73 extern void js_activate_timer();
74 extern void js_deactivate_timer();
75 extern void js_canvas_start_draw(void);
76 extern void js_canvas_draw_update(int x, int y, int w, int h);
77 extern void js_canvas_end_draw(void);
78 extern void js_canvas_draw_rect(int x, int y, int w, int h,
80 extern void js_canvas_clip_rect(int x, int y, int w, int h);
81 extern void js_canvas_unclip(void);
82 extern void js_canvas_draw_line(float x1, float y1, float x2, float y2,
83 int width, const char *colour);
84 extern void js_canvas_draw_poly(int *points, int npoints,
85 const char *fillcolour,
86 const char *outlinecolour);
87 extern void js_canvas_draw_circle(int x, int y, int r,
88 const char *fillcolour,
89 const char *outlinecolour);
90 extern int js_canvas_find_font_midpoint(int height, const char *fontptr);
91 extern void js_canvas_draw_text(int x, int y, int halign,
92 const char *colptr, const char *fontptr,
94 extern int js_canvas_new_blitter(int w, int h);
95 extern void js_canvas_free_blitter(int id);
96 extern void js_canvas_copy_to_blitter(int id, int x, int y, int w, int h);
97 extern void js_canvas_copy_from_blitter(int id, int x, int y, int w, int h);
98 extern void js_canvas_make_statusbar(void);
99 extern void js_canvas_set_statusbar(const char *text);
100 extern void js_canvas_set_size(int w, int h);
102 extern void js_dialog_init(const char *title);
103 extern void js_dialog_string(int i, const char *title, const char *initvalue);
104 extern void js_dialog_choices(int i, const char *title, const char *choicelist,
106 extern void js_dialog_boolean(int i, const char *title, int initvalue);
107 extern void js_dialog_launch(void);
108 extern void js_dialog_cleanup(void);
109 extern void js_focus_canvas(void);
112 * Call JS to get the date, and use that to initialise our random
113 * number generator to invent the first game seed.
115 void get_random_seed(void **randseed, int *randseedsize)
117 unsigned *ret = snewn(2, unsigned);
120 *randseedsize = 2*sizeof(unsigned);
124 * Fatal error, called in cases of complete despair such as when
125 * malloc() has returned NULL.
127 void fatal(char *fmt, ...)
132 strcpy(buf, "puzzle fatal error: ");
135 vsnprintf(buf+strlen(buf), sizeof(buf)-strlen(buf), fmt, ap);
141 void debug_printf(char *fmt, ...)
146 vsnprintf(buf, sizeof(buf), fmt, ap);
152 * Helper function that makes it easy to test strings that might be
155 int strnullcmp(const char *a, const char *b)
157 if (a == NULL || b == NULL)
158 return a != NULL ? +1 : b != NULL ? -1 : 0;
163 * HTMLish names for the colours allocated by the puzzle.
165 char **colour_strings;
169 * The global midend object.
173 /* ----------------------------------------------------------------------
176 int timer_active = FALSE;
177 void deactivate_timer(frontend *fe)
179 js_deactivate_timer();
180 timer_active = FALSE;
182 void activate_timer(frontend *fe)
189 void timer_callback(double tplus)
192 midend_timer(me, tplus);
195 /* ----------------------------------------------------------------------
196 * Helper function to resize the canvas, and variables to remember its
197 * size for other functions (e.g. trimming blitter rectangles).
199 static int canvas_w, canvas_h;
200 static void resize(void)
204 midend_size(me, &w, &h, FALSE);
205 js_canvas_set_size(w, h);
211 * HTML doesn't give us a default frontend colour of its own, so we
212 * just make up a lightish grey ourselves.
214 void frontend_default_colour(frontend *fe, float *output)
216 output[0] = output[1] = output[2] = 0.9F;
220 * Helper function called from all over the place to ensure the undo
221 * and redo buttons get properly enabled and disabled after every move
222 * or undo or new-game event.
224 static void update_undo_redo(void)
226 js_enable_undo_redo(midend_can_undo(me), midend_can_redo(me));
230 * Mouse event handlers called from JS.
232 void mousedown(int x, int y, int button)
234 button = (button == 0 ? LEFT_BUTTON :
235 button == 1 ? MIDDLE_BUTTON : RIGHT_BUTTON);
236 midend_process_key(me, x, y, button);
240 void mouseup(int x, int y, int button)
242 button = (button == 0 ? LEFT_RELEASE :
243 button == 1 ? MIDDLE_RELEASE : RIGHT_RELEASE);
244 midend_process_key(me, x, y, button);
248 void mousemove(int x, int y, int buttons)
250 int button = (buttons & 2 ? MIDDLE_DRAG :
251 buttons & 4 ? RIGHT_DRAG : LEFT_DRAG);
252 midend_process_key(me, x, y, button);
257 * Keyboard handler called from JS.
259 void key(int keycode, int charcode, const char *key, const char *chr,
264 if (!strnullcmp(key, "Backspace") || !strnullcmp(key, "Del") ||
265 keycode == 8 || keycode == 46) {
266 keyevent = 127; /* Backspace / Delete */
267 } else if (!strnullcmp(key, "Enter") || keycode == 13) {
268 keyevent = 13; /* return */
269 } else if (!strnullcmp(key, "Left") || keycode == 37) {
270 keyevent = CURSOR_LEFT;
271 } else if (!strnullcmp(key, "Up") || keycode == 38) {
272 keyevent = CURSOR_UP;
273 } else if (!strnullcmp(key, "Right") || keycode == 39) {
274 keyevent = CURSOR_RIGHT;
275 } else if (!strnullcmp(key, "Down") || keycode == 40) {
276 keyevent = CURSOR_DOWN;
277 } else if (!strnullcmp(key, "End") || keycode == 35) {
279 * We interpret Home, End, PgUp and PgDn as numeric keypad
280 * controls regardless of whether they're the ones on the
281 * numeric keypad (since we can't tell). The effect of
282 * this should only be that the non-numeric-pad versions
283 * of those keys generate directions in 8-way movement
284 * puzzles like Cube and Inertia.
286 keyevent = MOD_NUM_KEYPAD | '1';
287 } else if (!strnullcmp(key, "PageDown") || keycode==34) {
288 keyevent = MOD_NUM_KEYPAD | '3';
289 } else if (!strnullcmp(key, "Home") || keycode==36) {
290 keyevent = MOD_NUM_KEYPAD | '7';
291 } else if (!strnullcmp(key, "PageUp") || keycode==33) {
292 keyevent = MOD_NUM_KEYPAD | '9';
293 } else if (chr && chr[0] && !chr[1]) {
294 keyevent = chr[0] & 0xFF;
295 } else if (keycode >= 96 && keycode < 106) {
296 keyevent = MOD_NUM_KEYPAD | ('0' + keycode - 96);
297 } else if (keycode >= 65 && keycode <= 90) {
298 keyevent = keycode + (shift ? 0 : 32);
299 } else if (keycode >= 48 && keycode <= 57) {
304 if (shift && keyevent >= 0x100)
305 keyevent |= MOD_SHFT;
308 if (keyevent >= 0x100)
309 keyevent |= MOD_CTRL;
314 midend_process_key(me, 0, 0, keyevent);
320 * Helper function called from several places to update the permalinks
321 * whenever a new game is created.
323 static void update_permalinks(void)
326 desc = midend_get_game_id(me);
327 seed = midend_get_random_seed(me);
328 js_update_permalinks(desc, seed);
334 * Callback from the midend when the game ids change, so we can update
337 static void ids_changed(void *ignored)
342 /* ----------------------------------------------------------------------
343 * Implementation of the drawing API by calling Javascript canvas
344 * drawing functions. (Well, half of it; the other half is on the JS
347 static void js_start_draw(void *handle)
349 js_canvas_start_draw();
352 static void js_clip(void *handle, int x, int y, int w, int h)
354 js_canvas_clip_rect(x, y, w, h);
357 static void js_unclip(void *handle)
362 static void js_draw_text(void *handle, int x, int y, int fonttype,
363 int fontsize, int align, int colour, char *text)
368 sprintf(fontstyle, "%dpx %s", fontsize,
369 fonttype == FONT_FIXED ? "monospace" : "sans-serif");
371 if (align & ALIGN_VCENTRE)
372 y += js_canvas_find_font_midpoint(fontsize, fontstyle);
374 if (align & ALIGN_HCENTRE)
376 else if (align & ALIGN_HRIGHT)
381 js_canvas_draw_text(x, y, halign, colour_strings[colour], fontstyle, text);
384 static void js_draw_rect(void *handle, int x, int y, int w, int h, int colour)
386 js_canvas_draw_rect(x, y, w, h, colour_strings[colour]);
389 static void js_draw_line(void *handle, int x1, int y1, int x2, int y2,
392 js_canvas_draw_line(x1, y1, x2, y2, 1, colour_strings[colour]);
395 static void js_draw_thick_line(void *handle, float thickness,
396 float x1, float y1, float x2, float y2,
399 js_canvas_draw_line(x1, y1, x2, y2, thickness, colour_strings[colour]);
402 static void js_draw_poly(void *handle, int *coords, int npoints,
403 int fillcolour, int outlinecolour)
405 js_canvas_draw_poly(coords, npoints,
406 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
407 colour_strings[outlinecolour]);
410 static void js_draw_circle(void *handle, int cx, int cy, int radius,
411 int fillcolour, int outlinecolour)
413 js_canvas_draw_circle(cx, cy, radius,
414 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
415 colour_strings[outlinecolour]);
419 int id; /* allocated on the js side */
420 int w, h; /* easier to retain here */
423 static blitter *js_blitter_new(void *handle, int w, int h)
425 blitter *bl = snew(blitter);
428 bl->id = js_canvas_new_blitter(w, h);
432 static void js_blitter_free(void *handle, blitter *bl)
434 js_canvas_free_blitter(bl->id);
438 static void trim_rect(int *x, int *y, int *w, int *h)
443 * Reduce the size of the copied rectangle to stop it going
444 * outside the bounds of the canvas.
447 /* Transform from x,y,w,h form into coordinates of all edges */
453 /* Clip each coordinate at both extremes of the canvas */
454 x0 = (x0 < 0 ? 0 : x0 > canvas_w ? canvas_w : x0);
455 x1 = (x1 < 0 ? 0 : x1 > canvas_w ? canvas_w : x1);
456 y0 = (y0 < 0 ? 0 : y0 > canvas_h ? canvas_h : y0);
457 y1 = (y1 < 0 ? 0 : y1 > canvas_h ? canvas_h : y1);
459 /* Transform back into x,y,w,h to return */
466 static void js_blitter_save(void *handle, blitter *bl, int x, int y)
468 int w = bl->w, h = bl->h;
469 trim_rect(&x, &y, &w, &h);
471 js_canvas_copy_to_blitter(bl->id, x, y, w, h);
474 static void js_blitter_load(void *handle, blitter *bl, int x, int y)
476 int w = bl->w, h = bl->h;
477 trim_rect(&x, &y, &w, &h);
479 js_canvas_copy_from_blitter(bl->id, x, y, w, h);
482 static void js_draw_update(void *handle, int x, int y, int w, int h)
484 trim_rect(&x, &y, &w, &h);
486 js_canvas_draw_update(x, y, w, h);
489 static void js_end_draw(void *handle)
491 js_canvas_end_draw();
494 static void js_status_bar(void *handle, char *text)
496 js_canvas_set_statusbar(text);
499 static char *js_text_fallback(void *handle, const char *const *strings,
502 return dupstr(strings[0]); /* Emscripten has no trouble with UTF-8 */
505 const struct drawing_api js_drawing = {
521 NULL, NULL, NULL, NULL, NULL, NULL, /* {begin,end}_{doc,page,puzzle} */
522 NULL, NULL, /* line_width, line_dotted */
527 /* ----------------------------------------------------------------------
528 * Presets and game-configuration dialog support.
530 static game_params **presets;
531 static int custom_preset;
532 int have_presets_dropdown;
534 void select_appropriate_preset(void)
536 if (have_presets_dropdown) {
537 int preset = midend_which_preset(me);
538 js_select_preset(preset < 0 ? custom_preset : preset);
542 static config_item *cfg = NULL;
543 static int cfg_which;
546 * Set up a dialog box. This is pretty easy on the C side; most of the
547 * work is done in JS.
549 static void cfg_start(int which)
554 cfg = midend_get_config(me, which, &title);
557 js_dialog_init(title);
560 for (i = 0; cfg[i].type != C_END; i++) {
561 switch (cfg[i].type) {
563 js_dialog_string(i, cfg[i].name, cfg[i].sval);
566 js_dialog_boolean(i, cfg[i].name, cfg[i].ival);
569 js_dialog_choices(i, cfg[i].name, cfg[i].sval, cfg[i].ival);
578 * Callbacks from JS when the OK button is clicked, to return the
579 * final state of each control.
581 void dlg_return_sval(int index, const char *val)
583 sfree(cfg[index].sval);
584 cfg[index].sval = dupstr(val);
586 void dlg_return_ival(int index, int val)
588 cfg[index].ival = val;
592 * Called when the user clicks OK or Cancel. use_results will be TRUE
593 * or FALSE respectively, in those cases. We terminate the dialog box,
594 * unless the user selected an invalid combination of parameters.
596 static void cfg_end(int use_results)
602 char *err = midend_set_config(me, cfg_which, cfg);
606 * The settings were unacceptable, so leave the config box
607 * open for the user to adjust them and try again.
612 * New settings are fine; start a new game and close the
615 select_appropriate_preset();
624 * User hit Cancel. Close the dialog, but also we must still
625 * reselect the right element of the dropdown list.
627 * (Because: imagine you have a preset selected, and then you
628 * select Custom from the list, but change your mind and hit
629 * Esc. The Custom option will now still be selected in the
630 * list, whereas obviously it should show the preset you still
631 * _actually_ have selected. Worse still, it'll be the visible
632 * rather than invisible Custom option - see the comment in
633 * js_add_preset in emcclib.js - so you won't even be able to
634 * select Custom without a faffy workaround.)
636 select_appropriate_preset();
643 /* ----------------------------------------------------------------------
644 * Called from JS when a command is given to the puzzle by clicking a
645 * button or control of some sort.
650 case 0: /* specific game ID */
653 case 1: /* random game seed */
656 case 2: /* game parameter dropdown changed */
658 int i = js_get_selected_preset();
659 if (i == custom_preset) {
661 * The user selected 'Custom', so launch the config
664 if (thegame.can_configure) /* (double-check just in case) */
665 cfg_start(CFG_SETTINGS);
668 * The user selected a preset, so just switch straight
671 midend_set_params(me, presets[i]);
680 case 3: /* OK clicked in a config box */
684 case 4: /* Cancel clicked in a config box */
688 case 5: /* New Game */
689 midend_process_key(me, 0, 0, 'n');
693 case 6: /* Restart */
694 midend_restart_game(me);
699 midend_process_key(me, 0, 0, 'u');
704 midend_process_key(me, 0, 0, 'r');
709 if (thegame.can_solve) {
710 char *msg = midend_solve(me);
720 /* ----------------------------------------------------------------------
721 * Setup function called at page load time. It's called main() because
722 * that's the most convenient thing in Emscripten, but it's not main()
723 * in the usual sense of bounding the program's entire execution.
724 * Instead, this function returns once the initial puzzle is set up
725 * and working, and everything thereafter happens by means of JS event
726 * handlers sending us callbacks.
728 int main(int argc, char **argv)
735 * Instantiate a midend.
737 me = midend_new(NULL, &thegame, &js_drawing, NULL);
740 * Chuck in the HTML fragment ID if we have one (trimming the
741 * leading # off the front first). If that's invalid, we retain
742 * the error message and will display it at the end, after setting
743 * up a random puzzle as usual.
745 if (argc > 1 && argv[1][0] == '#' && argv[1][1] != '\0')
746 param_err = midend_game_id(me, argv[1] + 1);
751 * Create either a random game or the specified one, and set the
752 * canvas size appropriately.
758 * Create a status bar, if needed.
760 if (midend_wants_statusbar(me))
761 js_canvas_make_statusbar();
764 * Set up the game-type dropdown with presets and/or the Custom
765 * option. We remember the index of the Custom option (as
766 * custom_preset) so that we can easily treat it specially when
769 custom_preset = midend_num_presets(me);
770 if (custom_preset == 0) {
772 * This puzzle doesn't have selectable game types at all.
773 * Completely remove the drop-down list from the page.
775 js_remove_type_dropdown();
776 have_presets_dropdown = FALSE;
780 presets = snewn(custom_preset, game_params *);
781 for (i = 0; i < custom_preset; i++) {
783 midend_fetch_preset(me, i, &name, &presets[i]);
786 if (thegame.can_configure)
787 js_add_preset(NULL); /* the 'Custom' entry in the dropdown */
789 have_presets_dropdown = TRUE;
792 * Now ensure the appropriate element of the presets menu
793 * starts off selected, in case it isn't the first one in the
796 select_appropriate_preset();
800 * Remove the Solve button if the game doesn't support it.
802 if (!thegame.can_solve)
803 js_remove_solve_button();
806 * Retrieve the game's colours, and convert them into #abcdef type
809 colours = midend_colours(me, &ncolours);
810 colour_strings = snewn(ncolours, char *);
811 for (i = 0; i < ncolours; i++) {
813 sprintf(col, "#%02x%02x%02x",
814 (unsigned)(0.5 + 255 * colours[i*3+0]),
815 (unsigned)(0.5 + 255 * colours[i*3+1]),
816 (unsigned)(0.5 + 255 * colours[i*3+2]));
817 colour_strings[i] = dupstr(col);
821 * Request notification when the game ids change (e.g. if the user
822 * presses 'n', and also when Mines supersedes its game
823 * description), so that we can proactively update the permalink.
825 midend_request_id_changes(me, ids_changed, NULL);
828 * Draw the puzzle's initial state, and set up the permalinks and
829 * undo/redo greying out.
836 * If we were given an erroneous game ID in argv[1], now's the
837 * time to put up the error box about it, after we've fully set up
838 * a random puzzle. Then when the user clicks 'ok', we have a
842 js_error_box(param_err);
845 * Done. Return to JS, and await callbacks!