Files
puzzles/emcclib.js
Simon Tatham f6434e8496 Update web puzzles to current WASM-based Emscripten.
I presume this will improve performance. Also, if I've understood
correctly, WASM-based compiled web code is capable of automatically
growing its memory, which the previous asm.js build of the puzzles
could not do, and occasionally caused people to complain that if they
tried to play a _really big_ game in their browser, the JS would
eventually freeze because the emulated memory ran out.

I've been putting off doing this for ages because my previous
Emscripten build setup was so finicky that I didn't like to meddle
with it. But now that the new cmake system in this source tree makes
things generally easier, and particularly since I've just found out
that the up-to-date Emscripten is available as a Docker image (namely
"emscripten/emsdk"), this seemed like a good moment to give it a try.

The source and build changes required for this update weren't too
onerous. I was half expecting a huge API upheaval, and indeed there
was _some_ change, but very little:

 - in the JS initPuzzle function, move the call to Module.callMain()
   into Module.onRuntimeInitialized instead of doing it at the top
   level, because New Emscripten's .js output likes to load the
   accompanying .wasm file asynchronously, so you can't call the WASM
   main() until it actually exists.

 - in the JS-side library code, replace all uses of Emscripten's
   Pointer_stringify() function with the new name UTF8ToString(). (The
   new version also has an ASCIIToString(), so I guess the reason for
   the name change is that now you get to choose which character set
   you meant. I need to use UTF-8, so that the × and ÷ signs in Keen
   will work.)

 - set EXTRA_EXPORTED_RUNTIME_METHODS=[cwrap,callMain] on the emcc
   link command line, otherwise they aren't available for my JS setup
   code to call.

 - (removed -s ASM_JS=1 from the link options, though I'm not actually
   sure it made any difference one way or the other in the new WASM
   world)

 - be prepared for a set of .wasm files to show up as build products
   alongside the .js ones.

 - stop building with -DCMAKE_BUILD_TYPE=Release! I'm not sure why
   that was needed, but if I leave that flag on my cmake command line,
   the output .js file fails to embed my emccpre.js, so the initial
   call to initPuzzle() fails from the HTML wrapper page, meaning
   nothing at all happens.
2021-04-03 09:22:49 +01:00

702 lines
24 KiB
JavaScript

/*
* emcclib.js: one of the Javascript components of an Emscripten-based
* web/Javascript front end for Puzzles.
*
* The other parts of this system live in emcc.c 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.
*
* This file contains a set of Javascript functions which we insert
* into Emscripten's library object via the --js-library option; this
* allows us to provide JS code which can be called from the
* Emscripten-compiled C, mostly dealing with UI interaction of
* various kinds.
*/
mergeInto(LibraryManager.library, {
/*
* void js_debug(const char *message);
*
* A function to write a diagnostic to the Javascript console.
* Unused in production, but handy in development.
*/
js_debug: function(ptr) {
console.log(UTF8ToString(ptr));
},
/*
* void js_error_box(const char *message);
*
* A wrapper around Javascript's alert(), so the C code can print
* simple error message boxes (e.g. when invalid data is entered
* in a configuration dialog).
*/
js_error_box: function(ptr) {
alert(UTF8ToString(ptr));
},
/*
* void js_remove_type_dropdown(void);
*
* Get rid of the drop-down list on the web page for selecting
* game presets. Called at setup time if the game back end
* provides neither presets nor configurability.
*/
js_remove_type_dropdown: function() {
gametypelist.style.display = "none";
},
/*
* void js_remove_solve_button(void);
*
* Get rid of the Solve button on the web page. Called at setup
* time if the game doesn't support an in-game solve function.
*/
js_remove_solve_button: function() {
document.getElementById("solve").style.display = "none";
},
/*
* void js_add_preset(int menuid, const char *name, int value);
*
* Add a preset to the drop-down types menu, or to a submenu of
* it. 'menuid' specifies an index into our array of submenus
* where the item might be placed; 'value' specifies the number
* that js_get_selected_preset() will return when this item is
* clicked.
*/
js_add_preset: function(menuid, ptr, value) {
var name = UTF8ToString(ptr);
var item = document.createElement("li");
item.setAttribute("data-index", value);
var tick = document.createElement("span");
tick.appendChild(document.createTextNode("\u2713"));
tick.style.color = "transparent";
tick.style.paddingRight = "0.5em";
item.appendChild(tick);
item.appendChild(document.createTextNode(name));
gametypesubmenus[menuid].appendChild(item);
gametypeitems.push(item);
item.onclick = function(event) {
if (dlg_dimmer === null) {
gametypeselectedindex = value;
command(2);
}
}
},
/*
* int js_add_preset_submenu(int menuid, const char *name);
*
* Add a submenu in the presets menu hierarchy. Returns its index,
* for passing as the 'menuid' argument in further calls to
* js_add_preset or this function.
*/
js_add_preset_submenu: function(menuid, ptr, value) {
var name = UTF8ToString(ptr);
var item = document.createElement("li");
// We still create a transparent tick element, even though it
// won't ever be selected, to make submenu titles line up
// nicely with their neighbours.
var tick = document.createElement("span");
tick.appendChild(document.createTextNode("\u2713"));
tick.style.color = "transparent";
tick.style.paddingRight = "0.5em";
item.appendChild(tick);
item.appendChild(document.createTextNode(name));
var submenu = document.createElement("ul");
item.appendChild(submenu);
gametypesubmenus[menuid].appendChild(item);
var toret = gametypesubmenus.length;
gametypesubmenus.push(submenu);
return toret;
},
/*
* int js_get_selected_preset(void);
*
* Return the index of the currently selected value in the type
* dropdown.
*/
js_get_selected_preset: function() {
return gametypeselectedindex;
},
/*
* void js_select_preset(int n);
*
* Cause a different value to be selected in the type dropdown
* (for when the user selects values from the Custom configurer
* which turn out to exactly match a preset).
*/
js_select_preset: function(n) {
gametypeselectedindex = n;
for (var i in gametypeitems) {
var item = gametypeitems[i];
var tick = item.firstChild;
if (item.getAttribute("data-index") == n) {
tick.style.color = "inherit";
} else {
tick.style.color = "transparent";
}
}
},
/*
* void js_get_date_64(unsigned *p);
*
* Return the current date, in milliseconds since the epoch
* (Javascript's native format), as a 64-bit integer. Used to
* invent an initial random seed for puzzle generation.
*/
js_get_date_64: function(ptr) {
var d = (new Date()).valueOf();
setValue(ptr, d, 'i64');
},
/*
* void js_update_permalinks(const char *desc, const char *seed);
*
* Update the permalinks on the web page for a new game
* description and optional random seed. desc can never be NULL,
* but seed might be (if the game was generated by entering a
* descriptive id by hand), in which case we suppress display of
* the random seed permalink.
*/
js_update_permalinks: function(desc, seed) {
desc = UTF8ToString(desc);
permalink_desc.href = "#" + desc;
if (seed == 0) {
permalink_seed.style.display = "none";
} else {
seed = UTF8ToString(seed);
permalink_seed.href = "#" + seed;
permalink_seed.style.display = "inline";
}
},
/*
* void js_enable_undo_redo(int undo, int redo);
*
* Set the enabled/disabled states of the undo and redo buttons,
* after a move.
*/
js_enable_undo_redo: function(undo, redo) {
disable_menu_item(undo_button, (undo == 0));
disable_menu_item(redo_button, (redo == 0));
},
/*
* void js_activate_timer();
*
* Start calling the C timer_callback() function every 20ms.
*/
js_activate_timer: function() {
if (timer === null) {
timer_reference_date = (new Date()).valueOf();
timer = setInterval(function() {
var now = (new Date()).valueOf();
timer_callback((now - timer_reference_date) / 1000.0);
timer_reference_date = now;
return true;
}, 20);
}
},
/*
* void js_deactivate_timer();
*
* Stop calling the C timer_callback() function every 20ms.
*/
js_deactivate_timer: function() {
if (timer !== null) {
clearInterval(timer);
timer = null;
}
},
/*
* void js_canvas_start_draw(void);
*
* Prepare to do some drawing on the canvas.
*/
js_canvas_start_draw: function() {
ctx = offscreen_canvas.getContext('2d');
update_xmin = update_xmax = update_ymin = update_ymax = undefined;
},
/*
* void js_canvas_draw_update(int x, int y, int w, int h);
*
* Mark a rectangle of the off-screen canvas as needing to be
* copied to the on-screen one.
*/
js_canvas_draw_update: function(x, y, w, h) {
/*
* Currently we do this in a really simple way, just by taking
* the smallest rectangle containing all updates so far. We
* could instead keep the data in a richer form (e.g. retain
* multiple smaller rectangles needing update, and only redraw
* the whole thing beyond a certain threshold) but this will
* do for now.
*/
if (update_xmin === undefined || update_xmin > x) update_xmin = x;
if (update_ymin === undefined || update_ymin > y) update_ymin = y;
if (update_xmax === undefined || update_xmax < x+w) update_xmax = x+w;
if (update_ymax === undefined || update_ymax < y+h) update_ymax = y+h;
},
/*
* void js_canvas_end_draw(void);
*
* Finish the drawing, by actually copying the newly drawn stuff
* to the on-screen canvas.
*/
js_canvas_end_draw: function() {
if (update_xmin !== undefined) {
var onscreen_ctx = onscreen_canvas.getContext('2d');
onscreen_ctx.drawImage(offscreen_canvas,
update_xmin, update_ymin,
update_xmax - update_xmin,
update_ymax - update_ymin,
update_xmin, update_ymin,
update_xmax - update_xmin,
update_ymax - update_ymin);
}
ctx = null;
},
/*
* void js_canvas_draw_rect(int x, int y, int w, int h,
* const char *colour);
*
* Draw a rectangle.
*/
js_canvas_draw_rect: function(x, y, w, h, colptr) {
ctx.fillStyle = UTF8ToString(colptr);
ctx.fillRect(x, y, w, h);
},
/*
* void js_canvas_clip_rect(int x, int y, int w, int h);
*
* Set a clipping rectangle.
*/
js_canvas_clip_rect: function(x, y, w, h) {
ctx.save();
ctx.beginPath();
ctx.rect(x, y, w, h);
ctx.clip();
},
/*
* void js_canvas_unclip(void);
*
* Reset to no clipping.
*/
js_canvas_unclip: function() {
ctx.restore();
},
/*
* void js_canvas_draw_line(float x1, float y1, float x2, float y2,
* int width, const char *colour);
*
* Draw a line. We must adjust the coordinates by 0.5 because
* Javascript's canvas coordinates appear to be pixel corners,
* whereas we want pixel centres. Also, we manually draw the pixel
* at each end of the line, which our clients will expect but
* Javascript won't reliably do by default (in common with other
* Postscriptish drawing frameworks).
*/
js_canvas_draw_line: function(x1, y1, x2, y2, width, colour) {
colour = UTF8ToString(colour);
ctx.beginPath();
ctx.moveTo(x1 + 0.5, y1 + 0.5);
ctx.lineTo(x2 + 0.5, y2 + 0.5);
ctx.lineWidth = width;
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
ctx.strokeStyle = colour;
ctx.stroke();
ctx.fillStyle = colour;
ctx.fillRect(x1, y1, 1, 1);
ctx.fillRect(x2, y2, 1, 1);
},
/*
* void js_canvas_draw_poly(int *points, int npoints,
* const char *fillcolour,
* const char *outlinecolour);
*
* Draw a polygon.
*/
js_canvas_draw_poly: function(pointptr, npoints, fill, outline) {
ctx.beginPath();
ctx.moveTo(getValue(pointptr , 'i32') + 0.5,
getValue(pointptr+4, 'i32') + 0.5);
for (var i = 1; i < npoints; i++)
ctx.lineTo(getValue(pointptr+8*i , 'i32') + 0.5,
getValue(pointptr+8*i+4, 'i32') + 0.5);
ctx.closePath();
if (fill != 0) {
ctx.fillStyle = UTF8ToString(fill);
ctx.fill();
}
ctx.lineWidth = '1';
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
ctx.strokeStyle = UTF8ToString(outline);
ctx.stroke();
},
/*
* void js_canvas_draw_circle(int x, int y, int r,
* const char *fillcolour,
* const char *outlinecolour);
*
* Draw a circle.
*/
js_canvas_draw_circle: function(x, y, r, fill, outline) {
ctx.beginPath();
ctx.arc(x + 0.5, y + 0.5, r, 0, 2*Math.PI);
if (fill != 0) {
ctx.fillStyle = UTF8ToString(fill);
ctx.fill();
}
ctx.lineWidth = '1';
ctx.lineCap = 'round';
ctx.lineJoin = 'round';
ctx.strokeStyle = UTF8ToString(outline);
ctx.stroke();
},
/*
* int js_canvas_find_font_midpoint(int height, const char *fontptr);
*
* Return the adjustment required for text displayed using
* ALIGN_VCENTRE. We want to place the midpoint between the
* baseline and the cap-height at the specified position; so this
* function returns the adjustment which, when added to the
* desired centre point, returns the y-coordinate at which you
* should put the baseline.
*
* There is no sensible method of querying this kind of font
* metric in Javascript, so instead we render a piece of test text
* to a throwaway offscreen canvas and then read the pixel data
* back out to find the highest and lowest pixels. That's good
* _enough_ (in that we only needed the answer to the nearest
* pixel anyway), but rather disgusting!
*
* Since this is a very expensive operation, we cache the results
* per (font,height) pair.
*/
js_canvas_find_font_midpoint: function(height, font) {
font = UTF8ToString(font);
// Reuse cached value if possible
if (midpoint_cache[font] !== undefined)
return midpoint_cache[font];
// Find the width of the string
var ctx1 = onscreen_canvas.getContext('2d');
ctx1.font = font;
var width = (ctx1.measureText(midpoint_test_str).width + 1) | 0;
// Construct a test canvas of appropriate size, initialise it to
// black, and draw the string on it in white
var measure_canvas = document.createElement('canvas');
var ctx2 = measure_canvas.getContext('2d');
ctx2.canvas.width = width;
ctx2.canvas.height = 2*height;
ctx2.fillStyle = "#000000";
ctx2.fillRect(0, 0, width, 2*height);
var baseline = (1.5*height) | 0;
ctx2.fillStyle = "#ffffff";
ctx2.font = font;
ctx2.fillText(midpoint_test_str, 0, baseline);
// Scan the contents of the test canvas to find the top and bottom
// set pixels.
var pixels = ctx2.getImageData(0, 0, width, 2*height).data;
var ymin = 2*height, ymax = -1;
for (var y = 0; y < 2*height; y++) {
for (var x = 0; x < width; x++) {
if (pixels[4*(y*width+x)] != 0) {
if (ymin > y) ymin = y;
if (ymax < y) ymax = y;
break;
}
}
}
var ret = (baseline - (ymin + ymax) / 2) | 0;
midpoint_cache[font] = ret;
return ret;
},
/*
* void js_canvas_draw_text(int x, int y, int halign,
* const char *colptr, const char *fontptr,
* const char *text);
*
* Draw text. Vertical alignment has been taken care of on the C
* side, by optionally calling the above function. Horizontal
* alignment is handled here, since we can get the canvas draw
* function to do it for us with almost no extra effort.
*/
js_canvas_draw_text: function(x, y, halign, colptr, fontptr, text) {
ctx.font = UTF8ToString(fontptr);
ctx.fillStyle = UTF8ToString(colptr);
ctx.textAlign = (halign == 0 ? 'left' :
halign == 1 ? 'center' : 'right');
ctx.textBaseline = 'alphabetic';
ctx.fillText(UTF8ToString(text), x, y);
},
/*
* int js_canvas_new_blitter(int w, int h);
*
* Create a new blitter object, which is just an offscreen canvas
* of the specified size.
*/
js_canvas_new_blitter: function(w, h) {
var id = blittercount++;
blitters[id] = document.createElement("canvas");
blitters[id].width = w;
blitters[id].height = h;
return id;
},
/*
* void js_canvas_free_blitter(int id);
*
* Free a blitter (or rather, destroy our reference to it so JS
* can garbage-collect it, and also enforce that we don't
* accidentally use it again afterwards).
*/
js_canvas_free_blitter: function(id) {
blitters[id] = null;
},
/*
* void js_canvas_copy_to_blitter(int id, int x, int y, int w, int h);
*
* Copy from the puzzle image to a blitter. The size is passed to
* us, partly so we don't have to remember the size of each
* blitter, but mostly so that the C side can adjust the copy
* rectangle in the case where it partially overlaps the edge of
* the screen.
*/
js_canvas_copy_to_blitter: function(id, x, y, w, h) {
var blitter_ctx = blitters[id].getContext('2d');
blitter_ctx.drawImage(offscreen_canvas,
x, y, w, h,
0, 0, w, h);
},
/*
* void js_canvas_copy_from_blitter(int id, int x, int y, int w, int h);
*
* Copy from a blitter back to the puzzle image. As above, the
* size of the copied rectangle is passed to us from the C side
* and may already have been modified.
*/
js_canvas_copy_from_blitter: function(id, x, y, w, h) {
ctx.drawImage(blitters[id],
0, 0, w, h,
x, y, w, h);
},
/*
* void js_canvas_make_statusbar(void);
*
* Cause a status bar to exist. Called at setup time if the puzzle
* back end turns out to want one.
*/
js_canvas_make_statusbar: function() {
var statusholder = document.getElementById("statusbarholder");
statusbar = document.createElement("div");
statusbar.style.overflow = "hidden";
statusbar.style.width = (onscreen_canvas.width - 4) + "px";
statusholder.style.width = onscreen_canvas.width + "px";
statusbar.style.height = "1.2em";
statusbar.style.textAlign = "left";
statusbar.style.background = "#d8d8d8";
statusbar.style.borderLeft = '2px solid #c8c8c8';
statusbar.style.borderTop = '2px solid #c8c8c8';
statusbar.style.borderRight = '2px solid #e8e8e8';
statusbar.style.borderBottom = '2px solid #e8e8e8';
statusbar.appendChild(document.createTextNode(" "));
statusholder.appendChild(statusbar);
},
/*
* void js_canvas_set_statusbar(const char *text);
*
* Set the text in the status bar.
*/
js_canvas_set_statusbar: function(ptr) {
var text = UTF8ToString(ptr);
statusbar.replaceChild(document.createTextNode(text),
statusbar.lastChild);
},
/*
* void js_canvas_set_size(int w, int h);
*
* Set the size of the puzzle canvas. Called at setup, and every
* time the user picks new puzzle settings requiring a different
* size.
*/
js_canvas_set_size: function(w, h) {
onscreen_canvas.width = w;
offscreen_canvas.width = w;
if (statusbar !== null) {
statusbar.style.width = (w - 4) + "px";
document.getElementById("statusbarholder").style.width = w + "px";
}
resizable_div.style.width = w + "px";
onscreen_canvas.height = h;
offscreen_canvas.height = h;
},
/*
* void js_dialog_init(const char *title);
*
* Begin constructing a 'dialog box' which will be popped up in an
* overlay on top of the rest of the puzzle web page.
*/
js_dialog_init: function(titletext) {
dialog_init(UTF8ToString(titletext));
},
/*
* void js_dialog_string(int i, const char *title, const char *initvalue);
*
* Add a string control (that is, an edit box) to the dialog under
* construction.
*/
js_dialog_string: function(index, title, initialtext) {
dlg_form.appendChild(document.createTextNode(UTF8ToString(title)));
var editbox = document.createElement("input");
editbox.type = "text";
editbox.value = UTF8ToString(initialtext);
dlg_form.appendChild(editbox);
dlg_form.appendChild(document.createElement("br"));
dlg_return_funcs.push(function() {
dlg_return_sval(index, editbox.value);
});
},
/*
* void js_dialog_choices(int i, const char *title, const char *choicelist,
* int initvalue);
*
* Add a choices control (i.e. a drop-down list) to the dialog
* under construction. The 'choicelist' parameter is unchanged
* from the way the puzzle back end will have supplied it: i.e.
* it's still encoded as a single string whose first character
* gives the separator.
*/
js_dialog_choices: function(index, title, choicelist, initvalue) {
dlg_form.appendChild(document.createTextNode(UTF8ToString(title)));
var dropdown = document.createElement("select");
var choicestr = UTF8ToString(choicelist);
var items = choicestr.slice(1).split(choicestr[0]);
var options = [];
for (var i in items) {
var option = document.createElement("option");
option.value = i;
option.appendChild(document.createTextNode(items[i]));
if (i == initvalue) option.selected = true;
dropdown.appendChild(option);
options.push(option);
}
dlg_form.appendChild(dropdown);
dlg_form.appendChild(document.createElement("br"));
dlg_return_funcs.push(function() {
var val = 0;
for (var i in options) {
if (options[i].selected) {
val = options[i].value;
break;
}
}
dlg_return_ival(index, val);
});
},
/*
* void js_dialog_boolean(int i, const char *title, int initvalue);
*
* Add a boolean control (a checkbox) to the dialog under
* construction. Checkboxes are generally expected to be sensitive
* on their label text as well as the box itself, so for this
* control we create an actual label rather than merely a text
* node (and hence we must allocate an id to the checkbox so that
* the label can refer to it).
*/
js_dialog_boolean: function(index, title, initvalue) {
var checkbox = document.createElement("input");
checkbox.type = "checkbox";
checkbox.id = "cb" + String(dlg_next_id++);
checkbox.checked = (initvalue != 0);
dlg_form.appendChild(checkbox);
var checkboxlabel = document.createElement("label");
checkboxlabel.setAttribute("for", checkbox.id);
checkboxlabel.textContent = UTF8ToString(title);
dlg_form.appendChild(checkboxlabel);
dlg_form.appendChild(document.createElement("br"));
dlg_return_funcs.push(function() {
dlg_return_ival(index, checkbox.checked ? 1 : 0);
});
},
/*
* void js_dialog_launch(void);
*
* Finish constructing a dialog, and actually display it, dimming
* everything else on the page.
*/
js_dialog_launch: function() {
dialog_launch(function(event) {
for (var i in dlg_return_funcs)
dlg_return_funcs[i]();
command(3); // OK
}, function(event) {
command(4); // Cancel
});
},
/*
* void js_dialog_cleanup(void);
*
* Stop displaying a dialog, and clean up the internal state
* associated with it.
*/
js_dialog_cleanup: function() {
dialog_cleanup();
},
/*
* void js_focus_canvas(void);
*
* Return keyboard focus to the puzzle canvas. Called after a
* puzzle-control button is pressed, which tends to have the side
* effect of taking focus away from the canvas.
*/
js_focus_canvas: function() {
onscreen_canvas.focus();
}
});