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!)
62 * Extern references to Javascript functions provided in emcclib.js.
64 extern void js_debug(const char *);
65 extern void js_error_box(const char *message);
66 extern void js_remove_type_dropdown(void);
67 extern void js_remove_solve_button(void);
68 extern void js_add_preset(const char *name);
69 extern int js_get_selected_preset(void);
70 extern void js_select_preset(int n);
71 extern void js_get_date_64(unsigned *p);
72 extern void js_update_permalinks(const char *desc, const char *seed);
73 extern void js_enable_undo_redo(int undo, int redo);
74 extern void js_activate_timer();
75 extern void js_deactivate_timer();
76 extern void js_canvas_start_draw(void);
77 extern void js_canvas_draw_update(int x, int y, int w, int h);
78 extern void js_canvas_end_draw(void);
79 extern void js_canvas_draw_rect(int x, int y, int w, int h,
81 extern void js_canvas_clip_rect(int x, int y, int w, int h);
82 extern void js_canvas_unclip(void);
83 extern void js_canvas_draw_line(float x1, float y1, float x2, float y2,
84 int width, const char *colour);
85 extern void js_canvas_draw_poly(int *points, int npoints,
86 const char *fillcolour,
87 const char *outlinecolour);
88 extern void js_canvas_draw_circle(int x, int y, int r,
89 const char *fillcolour,
90 const char *outlinecolour);
91 extern int js_canvas_find_font_midpoint(int height, const char *fontptr);
92 extern void js_canvas_draw_text(int x, int y, int halign,
93 const char *colptr, const char *fontptr,
95 extern int js_canvas_new_blitter(int w, int h);
96 extern void js_canvas_free_blitter(int id);
97 extern void js_canvas_copy_to_blitter(int id, int x, int y, int w, int h);
98 extern void js_canvas_copy_from_blitter(int id, int x, int y, int w, int h);
99 extern void js_canvas_make_statusbar(void);
100 extern void js_canvas_set_statusbar(const char *text);
101 extern void js_canvas_set_size(int w, int h);
103 extern void js_dialog_init(const char *title);
104 extern void js_dialog_string(int i, const char *title, const char *initvalue);
105 extern void js_dialog_choices(int i, const char *title, const char *choicelist,
107 extern void js_dialog_boolean(int i, const char *title, int initvalue);
108 extern void js_dialog_launch(void);
109 extern void js_dialog_cleanup(void);
110 extern void js_focus_canvas(void);
113 * Call JS to get the date, and use that to initialise our random
114 * number generator to invent the first game seed.
116 void get_random_seed(void **randseed, int *randseedsize)
118 unsigned *ret = snewn(2, unsigned);
121 *randseedsize = 2*sizeof(unsigned);
125 * Fatal error, called in cases of complete despair such as when
126 * malloc() has returned NULL.
128 void fatal(char *fmt, ...)
133 strcpy(buf, "puzzle fatal error: ");
136 vsnprintf(buf+strlen(buf), sizeof(buf)-strlen(buf), fmt, ap);
142 void debug_printf(char *fmt, ...)
147 vsnprintf(buf, sizeof(buf), fmt, ap);
153 * Helper function that makes it easy to test strings that might be
156 int strnullcmp(const char *a, const char *b)
158 if (a == NULL || b == NULL)
159 return a != NULL ? +1 : b != NULL ? -1 : 0;
164 * HTMLish names for the colours allocated by the puzzle.
166 char **colour_strings;
170 * The global midend object.
174 /* ----------------------------------------------------------------------
177 int timer_active = FALSE;
178 void deactivate_timer(frontend *fe)
180 js_deactivate_timer();
181 timer_active = FALSE;
183 void activate_timer(frontend *fe)
190 void timer_callback(double tplus)
193 midend_timer(me, tplus);
196 /* ----------------------------------------------------------------------
197 * Helper function to resize the canvas, and variables to remember its
198 * size for other functions (e.g. trimming blitter rectangles).
200 static int canvas_w, canvas_h;
201 static void resize(void)
205 midend_size(me, &w, &h, FALSE);
206 js_canvas_set_size(w, h);
212 * HTML doesn't give us a default frontend colour of its own, so we
213 * just make up a lightish grey ourselves.
215 void frontend_default_colour(frontend *fe, float *output)
217 output[0] = output[1] = output[2] = 0.9F;
221 * Helper function called from all over the place to ensure the undo
222 * and redo buttons get properly enabled and disabled after every move
223 * or undo or new-game event.
225 static void update_undo_redo(void)
227 js_enable_undo_redo(midend_can_undo(me), midend_can_redo(me));
231 * Mouse event handlers called from JS.
233 void mousedown(int x, int y, int button)
235 button = (button == 0 ? LEFT_BUTTON :
236 button == 1 ? MIDDLE_BUTTON : RIGHT_BUTTON);
237 midend_process_key(me, x, y, button);
241 void mouseup(int x, int y, int button)
243 button = (button == 0 ? LEFT_RELEASE :
244 button == 1 ? MIDDLE_RELEASE : RIGHT_RELEASE);
245 midend_process_key(me, x, y, button);
249 void mousemove(int x, int y, int buttons)
251 int button = (buttons & 2 ? MIDDLE_DRAG :
252 buttons & 4 ? RIGHT_DRAG : LEFT_DRAG);
253 midend_process_key(me, x, y, button);
258 * Keyboard handler called from JS.
260 void key(int keycode, int charcode, const char *key, const char *chr,
265 if (!strnullcmp(key, "Backspace") || !strnullcmp(key, "Del") ||
266 keycode == 8 || keycode == 46) {
267 keyevent = 127; /* Backspace / Delete */
268 } else if (!strnullcmp(key, "Enter") || keycode == 13) {
269 keyevent = 13; /* return */
270 } else if (!strnullcmp(key, "Left") || keycode == 37) {
271 keyevent = CURSOR_LEFT;
272 } else if (!strnullcmp(key, "Up") || keycode == 38) {
273 keyevent = CURSOR_UP;
274 } else if (!strnullcmp(key, "Right") || keycode == 39) {
275 keyevent = CURSOR_RIGHT;
276 } else if (!strnullcmp(key, "Down") || keycode == 40) {
277 keyevent = CURSOR_DOWN;
278 } else if (!strnullcmp(key, "End") || keycode == 35) {
280 * We interpret Home, End, PgUp and PgDn as numeric keypad
281 * controls regardless of whether they're the ones on the
282 * numeric keypad (since we can't tell). The effect of
283 * this should only be that the non-numeric-pad versions
284 * of those keys generate directions in 8-way movement
285 * puzzles like Cube and Inertia.
287 keyevent = MOD_NUM_KEYPAD | '1';
288 } else if (!strnullcmp(key, "PageDown") || keycode==34) {
289 keyevent = MOD_NUM_KEYPAD | '3';
290 } else if (!strnullcmp(key, "Home") || keycode==36) {
291 keyevent = MOD_NUM_KEYPAD | '7';
292 } else if (!strnullcmp(key, "PageUp") || keycode==33) {
293 keyevent = MOD_NUM_KEYPAD | '9';
294 } else if (chr && chr[0] && !chr[1]) {
295 keyevent = chr[0] & 0xFF;
296 } else if (keycode >= 96 && keycode < 106) {
297 keyevent = MOD_NUM_KEYPAD | ('0' + keycode - 96);
298 } else if (keycode >= 65 && keycode <= 90) {
299 keyevent = keycode + (shift ? 0 : 32);
300 } else if (keycode >= 48 && keycode <= 57) {
305 if (shift && keyevent >= 0x100)
306 keyevent |= MOD_SHFT;
309 if (keyevent >= 0x100)
310 keyevent |= MOD_CTRL;
315 midend_process_key(me, 0, 0, keyevent);
321 * Helper function called from several places to update the permalinks
322 * whenever a new game is created.
324 static void update_permalinks(void)
327 desc = midend_get_game_id(me);
328 seed = midend_get_random_seed(me);
329 js_update_permalinks(desc, seed);
335 * Callback from the midend when the game ids change, so we can update
338 static void ids_changed(void *ignored)
343 /* ----------------------------------------------------------------------
344 * Implementation of the drawing API by calling Javascript canvas
345 * drawing functions. (Well, half of it; the other half is on the JS
348 static void js_start_draw(void *handle)
350 js_canvas_start_draw();
353 static void js_clip(void *handle, int x, int y, int w, int h)
355 js_canvas_clip_rect(x, y, w, h);
358 static void js_unclip(void *handle)
363 static void js_draw_text(void *handle, int x, int y, int fonttype,
364 int fontsize, int align, int colour, char *text)
369 sprintf(fontstyle, "%dpx %s", fontsize,
370 fonttype == FONT_FIXED ? "monospace" : "sans-serif");
372 if (align & ALIGN_VCENTRE)
373 y += js_canvas_find_font_midpoint(fontsize, fontstyle);
375 if (align & ALIGN_HCENTRE)
377 else if (align & ALIGN_HRIGHT)
382 js_canvas_draw_text(x, y, halign, colour_strings[colour], fontstyle, text);
385 static void js_draw_rect(void *handle, int x, int y, int w, int h, int colour)
387 js_canvas_draw_rect(x, y, w, h, colour_strings[colour]);
390 static void js_draw_line(void *handle, int x1, int y1, int x2, int y2,
393 js_canvas_draw_line(x1, y1, x2, y2, 1, colour_strings[colour]);
396 static void js_draw_thick_line(void *handle, float thickness,
397 float x1, float y1, float x2, float y2,
400 js_canvas_draw_line(x1, y1, x2, y2, thickness, colour_strings[colour]);
403 static void js_draw_poly(void *handle, int *coords, int npoints,
404 int fillcolour, int outlinecolour)
406 js_canvas_draw_poly(coords, npoints,
407 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
408 colour_strings[outlinecolour]);
411 static void js_draw_circle(void *handle, int cx, int cy, int radius,
412 int fillcolour, int outlinecolour)
414 js_canvas_draw_circle(cx, cy, radius,
415 fillcolour >= 0 ? colour_strings[fillcolour] : NULL,
416 colour_strings[outlinecolour]);
420 int id; /* allocated on the js side */
421 int w, h; /* easier to retain here */
424 static blitter *js_blitter_new(void *handle, int w, int h)
426 blitter *bl = snew(blitter);
429 bl->id = js_canvas_new_blitter(w, h);
433 static void js_blitter_free(void *handle, blitter *bl)
435 js_canvas_free_blitter(bl->id);
439 static void trim_rect(int *x, int *y, int *w, int *h)
444 * Reduce the size of the copied rectangle to stop it going
445 * outside the bounds of the canvas.
448 /* Transform from x,y,w,h form into coordinates of all edges */
454 /* Clip each coordinate at both extremes of the canvas */
455 x0 = (x0 < 0 ? 0 : x0 > canvas_w ? canvas_w : x0);
456 x1 = (x1 < 0 ? 0 : x1 > canvas_w ? canvas_w : x1);
457 y0 = (y0 < 0 ? 0 : y0 > canvas_h ? canvas_h : y0);
458 y1 = (y1 < 0 ? 0 : y1 > canvas_h ? canvas_h : y1);
460 /* Transform back into x,y,w,h to return */
467 static void js_blitter_save(void *handle, blitter *bl, int x, int y)
469 int w = bl->w, h = bl->h;
470 trim_rect(&x, &y, &w, &h);
472 js_canvas_copy_to_blitter(bl->id, x, y, w, h);
475 static void js_blitter_load(void *handle, blitter *bl, int x, int y)
477 int w = bl->w, h = bl->h;
478 trim_rect(&x, &y, &w, &h);
480 js_canvas_copy_from_blitter(bl->id, x, y, w, h);
483 static void js_draw_update(void *handle, int x, int y, int w, int h)
485 trim_rect(&x, &y, &w, &h);
487 js_canvas_draw_update(x, y, w, h);
490 static void js_end_draw(void *handle)
492 js_canvas_end_draw();
495 static void js_status_bar(void *handle, char *text)
497 js_canvas_set_statusbar(text);
500 static char *js_text_fallback(void *handle, const char *const *strings,
503 return dupstr(strings[0]); /* Emscripten has no trouble with UTF-8 */
506 const struct drawing_api js_drawing = {
522 NULL, NULL, NULL, NULL, NULL, NULL, /* {begin,end}_{doc,page,puzzle} */
523 NULL, NULL, /* line_width, line_dotted */
528 /* ----------------------------------------------------------------------
529 * Presets and game-configuration dialog support.
531 static game_params **presets;
533 int have_presets_dropdown;
535 void select_appropriate_preset(void)
537 if (have_presets_dropdown) {
538 int preset = midend_which_preset(me);
539 js_select_preset(preset < 0 ? -1 : preset);
543 static config_item *cfg = NULL;
544 static int cfg_which;
547 * Set up a dialog box. This is pretty easy on the C side; most of the
548 * work is done in JS.
550 static void cfg_start(int which)
555 cfg = midend_get_config(me, which, &title);
558 js_dialog_init(title);
561 for (i = 0; cfg[i].type != C_END; i++) {
562 switch (cfg[i].type) {
564 js_dialog_string(i, cfg[i].name, cfg[i].sval);
567 js_dialog_boolean(i, cfg[i].name, cfg[i].ival);
570 js_dialog_choices(i, cfg[i].name, cfg[i].sval, cfg[i].ival);
579 * Callbacks from JS when the OK button is clicked, to return the
580 * final state of each control.
582 void dlg_return_sval(int index, const char *val)
584 sfree(cfg[index].sval);
585 cfg[index].sval = dupstr(val);
587 void dlg_return_ival(int index, int val)
589 cfg[index].ival = val;
593 * Called when the user clicks OK or Cancel. use_results will be TRUE
594 * or FALSE respectively, in those cases. We terminate the dialog box,
595 * unless the user selected an invalid combination of parameters.
597 static void cfg_end(int use_results)
603 char *err = midend_set_config(me, cfg_which, cfg);
607 * The settings were unacceptable, so leave the config box
608 * open for the user to adjust them and try again.
613 * New settings are fine; start a new game and close the
616 select_appropriate_preset();
625 * User hit Cancel. Close the dialog, but also we must still
626 * reselect the right element of the dropdown list.
628 * (Because: imagine you have a preset selected, and then you
629 * select Custom from the list, but change your mind and hit
630 * Esc. The Custom option will now still be selected in the
631 * list, whereas obviously it should show the preset you still
632 * _actually_ have selected. Worse still, it'll be the visible
633 * rather than invisible Custom option - see the comment in
634 * js_add_preset in emcclib.js - so you won't even be able to
635 * select Custom without a faffy workaround.)
637 select_appropriate_preset();
644 /* ----------------------------------------------------------------------
645 * Called from JS when a command is given to the puzzle by clicking a
646 * button or control of some sort.
651 case 0: /* specific game ID */
654 case 1: /* random game seed */
657 case 2: /* game parameter dropdown changed */
659 int i = js_get_selected_preset();
662 * The user selected 'Custom', so launch the config
665 if (thegame.can_configure) /* (double-check just in case) */
666 cfg_start(CFG_SETTINGS);
669 * The user selected a preset, so just switch straight
672 assert(i < npresets);
673 midend_set_params(me, presets[i]);
679 select_appropriate_preset(); /* sort out Custom/Customise */
683 case 3: /* OK clicked in a config box */
687 case 4: /* Cancel clicked in a config box */
691 case 5: /* New Game */
692 midend_process_key(me, 0, 0, 'n');
696 case 6: /* Restart */
697 midend_restart_game(me);
702 midend_process_key(me, 0, 0, 'u');
707 midend_process_key(me, 0, 0, 'r');
712 if (thegame.can_solve) {
713 char *msg = midend_solve(me);
723 /* ----------------------------------------------------------------------
724 * Setup function called at page load time. It's called main() because
725 * that's the most convenient thing in Emscripten, but it's not main()
726 * in the usual sense of bounding the program's entire execution.
727 * Instead, this function returns once the initial puzzle is set up
728 * and working, and everything thereafter happens by means of JS event
729 * handlers sending us callbacks.
731 int main(int argc, char **argv)
738 * Instantiate a midend.
740 me = midend_new(NULL, &thegame, &js_drawing, NULL);
743 * Chuck in the HTML fragment ID if we have one (trimming the
744 * leading # off the front first). If that's invalid, we retain
745 * the error message and will display it at the end, after setting
746 * up a random puzzle as usual.
748 if (argc > 1 && argv[1][0] == '#' && argv[1][1] != '\0')
749 param_err = midend_game_id(me, argv[1] + 1);
754 * Create either a random game or the specified one, and set the
755 * canvas size appropriately.
761 * Create a status bar, if needed.
763 if (midend_wants_statusbar(me))
764 js_canvas_make_statusbar();
767 * Set up the game-type dropdown with presets and/or the Custom
770 npresets = midend_num_presets(me);
773 * This puzzle doesn't have selectable game types at all.
774 * Completely remove the drop-down list from the page.
776 js_remove_type_dropdown();
777 have_presets_dropdown = FALSE;
781 presets = snewn(npresets, game_params *);
782 for (i = 0; i < npresets; i++) {
784 midend_fetch_preset(me, i, &name, &presets[i]);
787 if (thegame.can_configure)
788 js_add_preset(NULL); /* the 'Custom' entry in the dropdown */
790 have_presets_dropdown = TRUE;
793 * Now ensure the appropriate element of the presets menu
794 * starts off selected, in case it isn't the first one in the
797 select_appropriate_preset();
801 * Remove the Solve button if the game doesn't support it.
803 if (!thegame.can_solve)
804 js_remove_solve_button();
807 * Retrieve the game's colours, and convert them into #abcdef type
810 colours = midend_colours(me, &ncolours);
811 colour_strings = snewn(ncolours, char *);
812 for (i = 0; i < ncolours; i++) {
814 sprintf(col, "#%02x%02x%02x",
815 (unsigned)(0.5 + 255 * colours[i*3+0]),
816 (unsigned)(0.5 + 255 * colours[i*3+1]),
817 (unsigned)(0.5 + 255 * colours[i*3+2]));
818 colour_strings[i] = dupstr(col);
822 * Request notification when the game ids change (e.g. if the user
823 * presses 'n', and also when Mines supersedes its game
824 * description), so that we can proactively update the permalink.
826 midend_request_id_changes(me, ids_changed, NULL);
829 * Draw the puzzle's initial state, and set up the permalinks and
830 * undo/redo greying out.
837 * If we were given an erroneous game ID in argv[1], now's the
838 * time to put up the error box about it, after we've fully set up
839 * a random puzzle. Then when the user clicks 'ok', we have a
843 js_error_box(param_err);
846 * Done. Return to JS, and await callbacks!