wip: 47 tiles

content/programming/blog/tairu.tree

@@ -1,9 +1,12 @@
 %% title = "tairu - an interactive exploration of 2D autotiling techniques"
 scripts = [
+    "components/literate-programming.js",
     "tairu/cardinal-directions.js",
     "tairu/framework.js",
     "tairu/tairu.js",
     "tairu/tilemap-registry.js",
+    "tairu/tilemap.js",
+    "vendor/codejar.js",
 ]
 styles = ["tairu.css"]
 
@@ -17,11 +20,11 @@ styles = ["tairu.css"]
         - TODO: short videos demoing this here
 
 % id = "01HPD4XQPWJBTJ4DWAQE3J87C9"
-- once upon a time I heard of a technique called...\
+- once upon a time I stumbled upon a technique called...\
 **bitwise autotiling**
 
     % id = "01HPD4XQPW6VK3FDW5QRCE6HSS"
-    + I learned about it back when I was building 2D Minecraft clones using [Construct 2](https://www.construct.net/en/construct-2/manuals/construct-2), and I wanted my terrain to look nice as it does in Terraria
+    + I learned about it way back when I was just a kid building 2D Minecraft clones using [Construct 2](https://www.construct.net/en/construct-2/manuals/construct-2), and I wanted my terrain to look nice as it does in Terraria
 
         % id = "01HPD4XQPWJ1CE9ZVRW98X7HE6"
         - Construct 2 was one of my first programming experiences and the first game engine I truly actually liked :smile:
@@ -112,6 +115,10 @@ styles = ["tairu.css"]
 
         ![horizontal tile strip of 16 8x8 pixel metal tiles][pic:01HPMMR6DGKYTPZ9CK0WQWKNX5]
 
+            % id = "01HPQCCV4RB65D5Q4RANJKGC0D"
+            - **hint:** you can actually just use the original image, but use a lookup table from these indices to (x, y) coordinates.
+            this makes creating the assets a lot easier! (at the expense of some CPU time, though it is totally possible to offload tilemap rendering to the GPU - in that case it barely even matters.)
+
     % id = "01HPMVT9BMMEM4HT4ANZ40992P"
     - in JavaScript, drawing on a `<canvas>` using bitwise autotiling would look like this:
     ```javascript
@@ -193,21 +200,169 @@ styles = ["tairu.css"]
             - (I'm totally not trying to say this implementation is an L so far)
 
         % id = "01HPMVT9BMWG6QHQ125Z884W8Z"
-        + i'll cut right to the chase here and say it outright - the issue is that we simply don't have enough tiles to represent corner cases like this!
+        + i'll cut right to the chase here and say it outright - the issue is that we simply don't have enough tiles to represent *corner* cases like this!
 
             % id = "01HPMVT9BMQK8N1H68YV3J4CFQ"
             - see what I did there?
 
     % id = "01HPMVT9BMJTG3KD3K5EJ3BC93"
-        - the solution here is to introduce more tiles to handle these edge cases.
+    - the solution to that is to introduce more tiles to handle these edge cases.
 
-        TODO Explain
+        % classes.branch = "tileset-four-to-eight-demo"
+          id = "01HPQCCV4R5N97FJ1GS36HZJZ7"
+        - to represent the corners, we'll turn our four cardinal directions...
+
+        <ul class="directions-square">
+            <li class="east">E</li>
+            <li class="south">S</li>
+            <li class="west">W</li>
+            <li class="north">N</li>
+        </ul>
+
+        into eight *ordinal* directions:
+
+        <ul class="directions-square">
+            <li class="east">E</li>
+            <li class="south-east">SE</li>
+            <li class="south">S</li>
+            <li class="south-west">SW</li>
+            <li class="west">W</li>
+            <li class="north-west">NW</li>
+            <li class="north">N</li>
+            <li class="north-east"><a href="https://github.com/NoiseStudio/NoiseEngine/" title="NoiseEngine????">NE</a></li>
+        </ul>
+
+        % id = "01HPQCCV4R3GNEWZQFWGWH4Z6R"
+        - you might think that at this point we'll need 8 bits to represent our tiles, and that would make...
+
+        ***256 tiles!?***
+
+        nobody in their right mind would actually draw 256 separate tiles, right? ***RIGHT???***
+
+            % template = true
+              id = "01HPQCCV4RX13VR4DJAP2F9PFA"
+            - ...right! if you experiment with the bit combinations, you'll quickly find out that there is no difference if, relative to a single center tile, we have tiles on the corners:
+
+            <canvas
+                is="tairu-editor"
+                data-tilemap-id="bitwiseAutotilingCorners"
+                data-tile-size="40"
+            >
+                Your browser does not support &lt;canvas&gt;.
+                <img class="resource" src="{% pic 01HPMMR6DGKYTPZ9CK0WQWKNX5 %}" data-tairu-tileset="1">
+            </canvas>
+
+            these should all render the same way, despite technically having some [new neighbors](https://en.wikipedia.org/wiki/Moore_neighborhood).
+
+            % classes.branch = "tileset-four-to-eight-demo"
+              id = "01HPQCCV4RHZ8A7VMT2KM7T27P"
+            - what we can do about this is to ignore corners whenever zero or one of the tiles at their cardinal directions is connected -
+            for example, in the case of `E | SE | S`:
+
+            <ul class="directions-square e-s">
+                <li class="east">E</li>
+                <li class="south-east">SE</li>
+                <li class="south">S</li>
+            </ul>
+
+            we can completely ignore what happens in the northeast, northwest, and southwest, because the tile's cardinal directions do not fully contain any of these direction pairs.
+
+            % id = "01HPQCCV4R557T2SN7ES7Z4EJ7"
+            - we can verify this logic with a bit of code; with a bit of luck, we should be able to narrow down our tileset into something a lot more manageable.
+
+                + we'll start off by defining a bunch of variables to represent our ordinal directions:
+
+                ```javascript ordinal-directions
+                const E = 0b00000001;
+                const SE = 0b00000010;
+                const S = 0b00000100;
+                const SW = 0b00001000;
+                const W = 0b00010000;
+                const NW = 0b00100000;
+                const N = 0b01000000;
+                const NE = 0b10000000;
+                const ALL = E | SE | S | SW | W | NW | N | NE;
+                ```
+
+                as I've already said, we represent each direction using a single bit.
+
+                    - I'm using JavaScript by the way, because it's the native programming language of your web browser. read on to the end of this tangent to see why.
+
+                - now I don't know about you, but I find the usual C-style way of checking whether a bit is set extremely hard to read, so let's take care of that:
+
+                ```javascript ordinal-directions
+                function isSet(integer, bit) {
+                    return (integer & bit) == bit;
+                }
+                ```
+
+                - now we can write a function that will remove the aforementioned redundancies.
+                the logic is quite simple - for southeast, we only allow it to be set if both south and east are also set, and so on and so forth.
+
+                ```javascript ordinal-directions
+                // t is a tile index; variable name is short for brevity
+                function removeRedundancies(t) {
+                    if (isSet(t, SE) && (!isSet(t, S) || !isSet(t, E))) {
+                        t &= ~SE;
+                    }
+                    if (isSet(t, SW) && (!isSet(t, S) || !isSet(t, W))) {
+                        t &= ~SW;
+                    }
+                    if (isSet(t, NW) && (!isSet(t, N) || !isSet(t, W))) {
+                        t &= ~NW;
+                    }
+                    if (isSet(t, NE) && (!isSet(t, N) || !isSet(t, E))) {
+                        t &= ~NE;
+                    }
+                    return t;
+                }
+                ```
+
+                - with that, we can find a set of all unique non-redundant combinations:
+
+                ```javascript ordinal-directions
+                function ordinalDirections() {
+                    let unique = new Set();
+                    for (let i = 0; i <= ALL; ++i) {
+                        unique.add(removeRedundancies(i));
+                    }
+                    return Array.from(unique).sort((a, b) => a - b);
+                }
+                ```
+
+                    - by the way, I find it quite funny how JavaScript's [`Array.prototype.sort`] defaults to ASCII ordering *for all types.*
+                    even numbers! ain't that silly?
+
+                    [`Array.prototype.sort`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort
+
+                - and now it's time to _Let It Cook™_:
+
+                ```javascript ordinal-directions
+                let dirs = ordinalDirections();
+                console.log(dirs.length);
+                ```
+
+                ```output ordinal-directions
+                47
+                ```
+
+                    - forty seven! that's how many unique tiles we actually need.
+
+                    - you may find pixel art tutorials saying you need forty *eight* and not forty *seven*, but that is not quite correct -
+                    the forty eighth tile is actually just the empty tile! saying it's part of the tileset is quite misleading IMO.
+
+                    - phew... the nesting's getting quite unwieldy, let's wrap up this tangent and return back to doing some bitwise autotiling!
+
+        - so in reality we actually only need 47 tiles and not 256 - that's a whole lot less, that's 81.640625% less tiles we have to draw!
+
+            - and it's even possible to autogenerate most of them given just a few smaller 4x4 pieces - but for now, let's not go down that path.\
+            maybe another time.
 
 % id = "01HPD4XQPWT9N8X9BD9GKWD78F"
-- bitwise autotiling is a really cool technique that I've used in plenty of games in the past
+- bitwise autotiling is a really cool technique that I've used in plenty of games in the past.
 
     % id = "01HPD4XQPW5FQY8M04S6JEBDHQ"
-    - as I mentioned before, [I've known it since my Construct 2 days][branch:01HPD4XQPW6VK3FDW5QRCE6HSS], but when it comes to my released games [Planet Overgamma] would probably be the first to utilize it properly
+    - as I mentioned before, [I've known it since my Construct 2 days][branch:01HPD4XQPW6VK3FDW5QRCE6HSS], but when it comes to any released games [Planet Overgamma] would probably be the first to utilize it properly.
 
     TODO video of some Planet Overgamma gameplay showing the autotiling in action
 
@@ -215,7 +370,7 @@ styles = ["tairu.css"]
 
         % id = "01HPJ8GHDEN4XRPT1AJ1BTNTFJ"
         - this accursed game has been haunting me for years since; there have been many iterations.
-        he autotiling source code of the one in the video can be found [here][autotiling source code].
+        the autotiling source code of the one in the video can be found [here][autotiling source code].
 
         [autotiling source code]: https://github.com/liquidev/planet-overgamma/blob/classic/jam/map.lua#L209
 
@@ -223,19 +378,20 @@ styles = ["tairu.css"]
 + but one day I found a really cool project called [Tilekit](https://rxi.itch.io/tilekit)
 
     % id = "01HPD4XQPW11EQTBDQSGXW3S52"
-    + (of course it's really cool, after all rxi made it)
+    + (of course it's really cool, after all [rxi](https://github.com/rxi) made it)
 
         % id = "01HPD4XQPWYHS327BV586SB085"
-        - for context rxi is the genius behind the Lua-powered, simple, and modular text editor `lite` that I was using for quite a while
+        - for context rxi is the genius behind the Lua-powered, simple, and modular text editor [lite](https://github.com/rxi/lite) that I was using for quite a while
 
             % id = "01HPD4XQPWJ9QAQ5MF2J5JBB8M"
-            - after a while I switched to a fork - Lite XL, which had better font rendering and more features
+            - after a while I switched to a fork - [Lite XL](https://github.com/lite-xl/lite-xl), which had better font rendering and more features
 
             % id = "01HPD4XQPWB11TZSX5VAAJ6TCD"
             - I stopped using it because VS Code was just more feature packed and usable; no need to reinvent the wheel, rust-analyzer *just works.*
 
                 % id = "01HPD4XQPW3G7BXTBBTD05MB8V"
-                - the LSP plugin for Lite XL had some issues around autocompletions not filling in properly :pensive:\
+                - the LSP plugin for Lite XL had some issues around autocompletions not filling in properly :pensive:
+
                 it's likely a lot better now, but back then I decided this is too much for my nerves.
                 while tinkering with your editor is something really cool, in my experience it's only cool up to a point.
 
@@ -267,27 +423,10 @@ styles = ["tairu.css"]
             % id = "01HPD4XQPWP847T0EAM0FJ88T4"
             - then vines
 
+    - well... it's even simpler than that in terms of graphical presentation, but we'll get to that.
+
     % id = "01HPD4XQPWK58Z63X6962STADR"
     - I mean, after all - bitwise autotiling is basically a clever solution to an `if` complexity problem, so why not extend that with more logic and rules and stuff to let you build more complex maps?
 
         % id = "01HPJ8GHDFRA2SPNHKJYD0SYPP"
         - of course Tilekit's solution is a lot more simple, streamlined, and user-friendly, but you get the gist.
-
-% id = "01HPD4XQPW4Y075XWJCT6AATB2"
-- ever since then I've been wanting to build something just like Tilekit, but in the form of an educational, interactive blog post to demonstrate the ideas in a fun way
-
-    % id = "01HPD4XQPWR8J9WCNBNCTJERZS"
-    - and what you're reading is the result of that.
-
-% id = "01HPD4XQPW1EP8YHACRJVMA0GM"
-- so let's get going! first, we'll build a basic tile editor using JavaScript.
-
-    % id = "01HPD4XQPWPNRTVJFNFGNHJMG1"
-    + not my favorite language, but we're on the Web so it's not like we have much more of a choice.
-
-        % id = "01HPD4XQPWGK7M4XJYC99XE4T6"
-        - I could use TypeScript, but this page follows a philosophy of not introducing complexity where I can deal without it.
-        TypeScript is totally cool, but not necessary.
-
-    % id = "01HPD4XQPWAE0ZH46WME6WJSVP"
-    - I'll be using Web Components (in particular, custom elements) combined with canvas to add stuff onto the page.

crates/treehouse/src/html/markdown.rs

@@ -227,16 +227,29 @@ where
                     self.write_newline()?;
                 }
                 match info {
-                    CodeBlockKind::Fenced(info) => {
+                    CodeBlockKind::Fenced(language) => match CodeBlockMode::parse(&language) {
-                        let lang = info.split(' ').next().unwrap();
+                        CodeBlockMode::PlainText => self.write("<pre><code>"),
-                        if lang.is_empty() {
+                        CodeBlockMode::SyntaxHighlightOnly { language } => {
-                            self.write("<pre><code>")
-                        } else {
                             self.write("<pre><code class=\"language-")?;
-                            escape_html(&mut self.writer, lang)?;
+                            escape_html(&mut self.writer, language)?;
                             self.write("\">")
                         }
+                        CodeBlockMode::LiterateProgram {
+                            language,
+                            kind,
+                            program_name,
+                        } => {
+                            self.write(match kind {
+                                LiterateCodeKind::Input => "<th-literate-editor ",
+                                LiterateCodeKind::Output => "<th-literate-output ",
+                            })?;
+                            self.write("data-program=\"")?;
+                            escape_html(&mut self.writer, program_name)?;
+                            self.write("\" data-language=\"")?;
+                            escape_html(&mut self.writer, language)?;
+                            self.write("\" role=\"code\">")
                         }
+                    },
                     CodeBlockKind::Indented => self.write("<pre><code>"),
                 }
             }
@@ -352,8 +365,21 @@ where
             Tag::BlockQuote => {
                 self.write("</blockquote>\n")?;
             }
-            Tag::CodeBlock(_) => {
+            Tag::CodeBlock(kind) => {
-                self.write("</code></pre>\n")?;
+                self.write(match kind {
+                    CodeBlockKind::Fenced(language) => match CodeBlockMode::parse(&language) {
+                        CodeBlockMode::LiterateProgram {
+                            kind: LiterateCodeKind::Input,
+                            ..
+                        } => "</th-literate-editor>",
+                        CodeBlockMode::LiterateProgram {
+                            kind: LiterateCodeKind::Output,
+                            ..
+                        } => "</th-literate-output>",
+                        _ => "</code></pre>",
+                    },
+                    _ => "</code></pre>\n",
+                })?;
                 self.in_code_block = false;
             }
             Tag::List(Some(_)) => {
@@ -518,6 +544,44 @@ where
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum LiterateCodeKind {
+    Input,
+    Output,
+}
+
+enum CodeBlockMode<'a> {
+    PlainText,
+    SyntaxHighlightOnly {
+        language: &'a str,
+    },
+    LiterateProgram {
+        language: &'a str,
+        kind: LiterateCodeKind,
+        program_name: &'a str,
+    },
+}
+
+impl<'a> CodeBlockMode<'a> {
+    fn parse(language: &'a str) -> CodeBlockMode<'a> {
+        if language.is_empty() {
+            CodeBlockMode::PlainText
+        } else if let Some((language, program_name)) = language.split_once(' ') {
+            CodeBlockMode::LiterateProgram {
+                language,
+                kind: if language == "output" {
+                    LiterateCodeKind::Output
+                } else {
+                    LiterateCodeKind::Input
+                },
+                program_name,
+            }
+        } else {
+            CodeBlockMode::SyntaxHighlightOnly { language }
+        }
+    }
+}
+
 /// Iterate over an `Iterator` of `Event`s, generate HTML for each `Event`, and
 /// push it to a `String`.
 ///

static/css/main.css

@@ -170,7 +170,9 @@ h4 {
 
 pre,
 code,
-kbd {
+kbd,
+th-literate-editor,
+th-literate-output {
     --recursive-mono: 1.0;
     --recursive-casl: 0.0;
     --recursive-slnt: 0.0;
@@ -210,19 +212,27 @@ body {
 
 /* Make code examples a little prettier by giving them visual separation from the rest of the page */
 
-code {
+code,
+th-literate-editor {
     padding: 3px 4px;
     background-color: var(--shaded-background);
     border-radius: 4px;
 }
 
+th-literate-editor,
+th-literate-output {
+    display: block;
+}
+
 kbd {
     padding: 3px 6px;
     border: 1px solid var(--border-1);
     border-radius: 6px;
 }
 
-pre {
+pre,
+th-literate-editor,
+th-literate-output {
     padding: 8px 12px;
     margin: 12px 0;
     background-color: var(--shaded-against-background);
@@ -231,11 +241,22 @@ pre {
     transition: background-color var(--transition-duration);
 }
 
-.tree summary:hover pre {
+th-literate-editor,
-    background-color: var(--shaded-against-background-twice);
+th-literate-output {
+    white-space: pre;
 }
 
-pre>code {
+.tree summary:hover {
+
+    & pre,
+    & th-literate-editor,
+    & th-literate-output {
+        background-color: var(--shaded-against-background-twice);
+    }
+}
+
+pre>code,
+th-literate-output>code {
     padding: 0;
     background: none;
     border-radius: 0px;
@@ -493,3 +514,40 @@ img[is="th-emoji"] {
     display: inline;
     animation: 4s hello-there forwards;
 }
+
+/* Literate programming support */
+
+th-literate-editor {
+    /* Override the cursor with an I-beam, because the editor captures clicks and does not bubble
+       them back up to the caller */
+    cursor: text;
+}
+
+th-literate-output {
+    position: relative;
+
+    & code {
+        display: block;
+    }
+
+    & code.error {
+        color: #e39393;
+    }
+
+    & code .return-value {
+        content: 'Return value: ';
+        opacity: 50%;
+    }
+
+    &::after {
+        content: 'Output';
+
+        padding: 8px;
+
+        position: absolute;
+        right: 0;
+        top: 0;
+
+        opacity: 50%;
+    }
+}

static/css/tairu.css

@@ -63,6 +63,11 @@
         font-size: 14px;
         position: absolute;
         color: #d3dce9;
+        text-shadow:
+            1px 0 0 #1a2039,
+            -1px 0 0 #1a2039,
+            0 1px 0 #1a2039,
+            0 -1px 0 #1a2039;
         padding: 2px 4px;
     }
 
@@ -99,11 +104,11 @@
     }
 
     & .x-1 {
-        background-position-x: 33.3333%;
+        background-position-x: calc(100% / 3);
     }
 
     & .x-2 {
-        background-position-x: 66.6666%;
+        background-position-x: calc(200% / 3);
     }
 
     & .x-3 {
@@ -115,14 +120,102 @@
     }
 
     & .y-1 {
-        background-position-y: 33.3333%;
+        background-position-y: calc(100% / 3);
     }
 
     & .y-2 {
-        background-position-y: 66.6666%;
+        background-position-y: calc(200% / 3);
     }
 
     & .y-3 {
         background-position-y: 100%;
     }
 }
+
+.tileset-four-to-eight-demo th-bc {
+    & .directions-square {
+        --recursive-wght: 900;
+        --recursive-casl: 0.0;
+        --recursive-slnt: 0.0;
+        --recursive-mono: 1.0;
+        color: #d3dce9;
+        text-shadow:
+            1px 0 0 #1a2039,
+            -1px 0 0 #1a2039,
+            0 1px 0 #1a2039,
+            0 -1px 0 #1a2039;
+
+        margin-block: 8px;
+        margin-left: 16px;
+        padding-left: 0;
+
+        width: 72px;
+        height: 72px;
+
+        background-image: url('../pic/01HPHVDRV0F0251MD0A2EG66C4-tilemap-heavy-metal-16+pixel+width160.png');
+        background-size: 400%;
+        background-position: 100% 100%;
+        image-rendering: crisp-edges;
+
+        position: relative;
+
+        li {
+            padding: 2px 4px;
+            position: absolute;
+        }
+
+        a {
+            text-decoration: none;
+            color: #d3dce9;
+            cursor: text;
+        }
+
+        & .east {
+            right: 0;
+            top: 50%;
+            transform: translateY(-50%);
+        }
+
+        & .south-east {
+            right: 0;
+            bottom: 0;
+        }
+
+        & .west {
+            left: 0;
+            top: 50%;
+            transform: translateY(-50%);
+        }
+
+        & .south-west {
+            left: 0;
+            bottom: 0;
+        }
+
+        & .north {
+            left: 50%;
+            top: 0;
+            transform: translateX(-50%);
+        }
+
+        & .north-west {
+            left: 0;
+            top: 0;
+        }
+
+        & .south {
+            left: 50%;
+            bottom: 0;
+            transform: translateX(-50%);
+        }
+
+        & .north-east {
+            right: 0;
+            top: 0;
+        }
+
+        &.e-s {
+            background-position: 0% 0%;
+        }
+    }
+}

static/js/components/literate-programming.js

@@ -0,0 +1,135 @@
+import { CodeJar } from "../vendor/codejar.js";
+
+let literatePrograms = new Map();
+
+function getLiterateProgram(name) {
+    if (literatePrograms.get(name) == null) {
+        literatePrograms.set(name, {
+            editors: [],
+            onChanged: [],
+        });
+    }
+    return literatePrograms.get(name);
+}
+
+function getLiterateProgramSourceCode(name) {
+    let sources = [];
+    let literateProgram = getLiterateProgram(name);
+    for (let editor of literateProgram.editors) {
+        sources.push(editor.textContent);
+    }
+    return sources.join("\n");
+}
+
+class LiterateEditor extends HTMLElement {
+    constructor() {
+        super();
+    }
+
+    connectedCallback() {
+        this.literateProgramName = this.getAttribute("data-program");
+        getLiterateProgram(this.literateProgramName).editors.push(this);
+
+        this.codeJar = CodeJar(this, LiterateEditor.highlight);
+        this.codeJar.onUpdate(() => {
+            let literateProgram = getLiterateProgram(this.literateProgramName);
+            for (let handler of literateProgram.onChanged) {
+                handler(this.literateProgramName);
+            }
+        })
+
+        this.addEventListener("click", event => event.preventDefault());
+    }
+
+    static highlight(editor) {
+        // TODO: Syntax highlighting
+    }
+}
+
+customElements.define("th-literate-editor", LiterateEditor);
+
+function debounce(callback, timeout) {
+    let timeoutId = 0;
+    return (...args) => {
+        clearTimeout(timeout);
+        timeoutId = window.setTimeout(() => callback(...args), timeout);
+    };
+}
+
+class LiterateOutput extends HTMLElement {
+    constructor() {
+        super();
+
+        this.clearResultsOnNextOutput = false;
+    }
+
+    connectedCallback() {
+        this.literateProgramName = this.getAttribute("data-program");
+        this.evaluate();
+
+        getLiterateProgram(this.literateProgramName).onChanged.push(_ => this.evaluate());
+    }
+
+    evaluate = () => {
+        // This is a small bit of debouncing. If we cleared the output right away, the page would
+        // jitter around irritatingly
+        this.clearResultsOnNextOutput = true;
+
+        if (this.worker != null) {
+            this.worker.terminate();
+        }
+        this.worker = new Worker(`${TREEHOUSE_SITE}/static/js/components/literate-programming/worker.js`, {
+            type: "module",
+            name: `evaluate LiterateOutput ${this.literateProgramName}`
+        });
+
+        this.worker.addEventListener("message", event => {
+            let message = event.data;
+            if (message.kind == "evalComplete") {
+                this.worker.terminate();
+            } else if (message.kind == "output") {
+                this.addOutput(message.output);
+            }
+        });
+
+        this.worker.postMessage({
+            action: "eval",
+            input: getLiterateProgramSourceCode(this.literateProgramName),
+        });
+    };
+
+    addOutput(output) {
+        if (this.clearResultsOnNextOutput) {
+            this.clearResultsOnNextOutput = false;
+            this.clearResults();
+        }
+
+        // Don't show anything if the function didn't return a value.
+        if (output.kind == "result" && output.message[0] === undefined) return;
+
+        let line = document.createElement("code");
+
+        line.classList.add("output");
+        line.classList.add(output.kind);
+
+        line.textContent = output.message.map(x => {
+            if (typeof x === "object") return JSON.stringify(x);
+            else return x + "";
+        }).join(" ");
+
+        if (output.kind == "result") {
+            let returnValueText = document.createElement("span");
+            returnValueText.classList.add("return-value");
+            returnValueText.textContent = "Return value: ";
+            line.insertBefore(returnValueText, line.firstChild);
+        }
+
+        this.appendChild(line);
+    }
+
+    clearResults() {
+        this.replaceChildren();
+    }
+}
+
+customElements.define("th-literate-output", LiterateOutput);

static/js/components/literate-programming/worker.js

@@ -0,0 +1,40 @@
+console = {
+    log(...message) {
+        postMessage({
+            kind: "output",
+            output: {
+                kind: "log",
+                message: [...message],
+            }
+        });
+    }
+};
+
+addEventListener("message", event => {
+    let message = event.data;
+    if (message.action == "eval") {
+        try {
+            let func = new Function(message.input);
+            let result = func.apply({});
+            postMessage({
+                kind: "output",
+                output: {
+                    kind: "result",
+                    message: [result],
+                }
+            });
+        } catch (error) {
+            postMessage({
+                kind: "output",
+                output: {
+                    kind: "error",
+                    message: [error.toString()],
+                }
+            });
+        }
+
+        postMessage({
+            kind: "evalComplete",
+        });
+    }
+});

static/js/tairu/tilemap-registry.js

@@ -29,5 +29,12 @@ export default {
         "   xxx   ",
         "         ",
     ]),
+    bitwiseAutotilingCorners: parseTilemap([
+        "     ",
+        " x x ",
+        "  x  ",
+        " x x ",
+        "     ",
+    ]),
 };
 

static/js/vendor/codejar.js

@@ -0,0 +1,511 @@
+const globalWindow = window;
+export function CodeJar(editor, highlight, opt = {}) {
+    const options = {
+        tab: '\t',
+        indentOn: /[({\[]$/,
+        moveToNewLine: /^[)}\]]/,
+        spellcheck: false,
+        catchTab: true,
+        preserveIdent: true,
+        addClosing: true,
+        history: true,
+        window: globalWindow,
+        ...opt,
+    };
+    const window = options.window;
+    const document = window.document;
+    const listeners = [];
+    const history = [];
+    let at = -1;
+    let focus = false;
+    let onUpdate = () => void 0;
+    let prev; // code content prior keydown event
+    editor.setAttribute('contenteditable', 'plaintext-only');
+    editor.setAttribute('spellcheck', options.spellcheck ? 'true' : 'false');
+    editor.style.outline = 'none';
+    editor.style.overflowWrap = 'break-word';
+    editor.style.overflowY = 'auto';
+    editor.style.whiteSpace = 'pre-wrap';
+    const doHighlight = (editor, pos) => {
+        highlight(editor, pos);
+    };
+    let isLegacy = false; // true if plaintext-only is not supported
+    if (editor.contentEditable !== 'plaintext-only')
+        isLegacy = true;
+    if (isLegacy)
+        editor.setAttribute('contenteditable', 'true');
+    const debounceHighlight = debounce(() => {
+        const pos = save();
+        doHighlight(editor, pos);
+        restore(pos);
+    }, 30);
+    let recording = false;
+    const shouldRecord = (event) => {
+        return !isUndo(event) && !isRedo(event)
+            && event.key !== 'Meta'
+            && event.key !== 'Control'
+            && event.key !== 'Alt'
+            && !event.key.startsWith('Arrow');
+    };
+    const debounceRecordHistory = debounce((event) => {
+        if (shouldRecord(event)) {
+            recordHistory();
+            recording = false;
+        }
+    }, 300);
+    const on = (type, fn) => {
+        listeners.push([type, fn]);
+        editor.addEventListener(type, fn);
+    };
+    on('keydown', event => {
+        if (event.defaultPrevented)
+            return;
+        prev = toString();
+        if (options.preserveIdent)
+            handleNewLine(event);
+        else
+            legacyNewLineFix(event);
+        if (options.catchTab)
+            handleTabCharacters(event);
+        if (options.addClosing)
+            handleSelfClosingCharacters(event);
+        if (options.history) {
+            handleUndoRedo(event);
+            if (shouldRecord(event) && !recording) {
+                recordHistory();
+                recording = true;
+            }
+        }
+        if (isLegacy && !isCopy(event))
+            restore(save());
+    });
+    on('keyup', event => {
+        if (event.defaultPrevented)
+            return;
+        if (event.isComposing)
+            return;
+        if (prev !== toString())
+            debounceHighlight();
+        debounceRecordHistory(event);
+        onUpdate(toString());
+    });
+    on('focus', _event => {
+        focus = true;
+    });
+    on('blur', _event => {
+        focus = false;
+    });
+    on('paste', event => {
+        recordHistory();
+        handlePaste(event);
+        recordHistory();
+        onUpdate(toString());
+    });
+    on('cut', event => {
+        recordHistory();
+        handleCut(event);
+        recordHistory();
+        onUpdate(toString());
+    });
+    function save() {
+        const s = getSelection();
+        const pos = { start: 0, end: 0, dir: undefined };
+        let { anchorNode, anchorOffset, focusNode, focusOffset } = s;
+        if (!anchorNode || !focusNode)
+            throw 'error1';
+        // If the anchor and focus are the editor element, return either a full
+        // highlight or a start/end cursor position depending on the selection
+        if (anchorNode === editor && focusNode === editor) {
+            pos.start = (anchorOffset > 0 && editor.textContent) ? editor.textContent.length : 0;
+            pos.end = (focusOffset > 0 && editor.textContent) ? editor.textContent.length : 0;
+            pos.dir = (focusOffset >= anchorOffset) ? '->' : '<-';
+            return pos;
+        }
+        // Selection anchor and focus are expected to be text nodes,
+        // so normalize them.
+        if (anchorNode.nodeType === Node.ELEMENT_NODE) {
+            const node = document.createTextNode('');
+            anchorNode.insertBefore(node, anchorNode.childNodes[anchorOffset]);
+            anchorNode = node;
+            anchorOffset = 0;
+        }
+        if (focusNode.nodeType === Node.ELEMENT_NODE) {
+            const node = document.createTextNode('');
+            focusNode.insertBefore(node, focusNode.childNodes[focusOffset]);
+            focusNode = node;
+            focusOffset = 0;
+        }
+        visit(editor, el => {
+            if (el === anchorNode && el === focusNode) {
+                pos.start += anchorOffset;
+                pos.end += focusOffset;
+                pos.dir = anchorOffset <= focusOffset ? '->' : '<-';
+                return 'stop';
+            }
+            if (el === anchorNode) {
+                pos.start += anchorOffset;
+                if (!pos.dir) {
+                    pos.dir = '->';
+                }
+                else {
+                    return 'stop';
+                }
+            }
+            else if (el === focusNode) {
+                pos.end += focusOffset;
+                if (!pos.dir) {
+                    pos.dir = '<-';
+                }
+                else {
+                    return 'stop';
+                }
+            }
+            if (el.nodeType === Node.TEXT_NODE) {
+                if (pos.dir != '->')
+                    pos.start += el.nodeValue.length;
+                if (pos.dir != '<-')
+                    pos.end += el.nodeValue.length;
+            }
+        });
+        editor.normalize(); // collapse empty text nodes
+        return pos;
+    }
+    function restore(pos) {
+        const s = getSelection();
+        let startNode, startOffset = 0;
+        let endNode, endOffset = 0;
+        if (!pos.dir)
+            pos.dir = '->';
+        if (pos.start < 0)
+            pos.start = 0;
+        if (pos.end < 0)
+            pos.end = 0;
+        // Flip start and end if the direction reversed
+        if (pos.dir == '<-') {
+            const { start, end } = pos;
+            pos.start = end;
+            pos.end = start;
+        }
+        let current = 0;
+        visit(editor, el => {
+            if (el.nodeType !== Node.TEXT_NODE)
+                return;
+            const len = (el.nodeValue || '').length;
+            if (current + len > pos.start) {
+                if (!startNode) {
+                    startNode = el;
+                    startOffset = pos.start - current;
+                }
+                if (current + len > pos.end) {
+                    endNode = el;
+                    endOffset = pos.end - current;
+                    return 'stop';
+                }
+            }
+            current += len;
+        });
+        if (!startNode)
+            startNode = editor, startOffset = editor.childNodes.length;
+        if (!endNode)
+            endNode = editor, endOffset = editor.childNodes.length;
+        // Flip back the selection
+        if (pos.dir == '<-') {
+            [startNode, startOffset, endNode, endOffset] = [endNode, endOffset, startNode, startOffset];
+        }
+        {
+            // If nodes not editable, create a text node.
+            const startEl = uneditable(startNode);
+            if (startEl) {
+                const node = document.createTextNode('');
+                startEl.parentNode?.insertBefore(node, startEl);
+                startNode = node;
+                startOffset = 0;
+            }
+            const endEl = uneditable(endNode);
+            if (endEl) {
+                const node = document.createTextNode('');
+                endEl.parentNode?.insertBefore(node, endEl);
+                endNode = node;
+                endOffset = 0;
+            }
+        }
+        s.setBaseAndExtent(startNode, startOffset, endNode, endOffset);
+        editor.normalize(); // collapse empty text nodes
+    }
+    function uneditable(node) {
+        while (node && node !== editor) {
+            if (node.nodeType === Node.ELEMENT_NODE) {
+                const el = node;
+                if (el.getAttribute('contenteditable') == 'false') {
+                    return el;
+                }
+            }
+            node = node.parentNode;
+        }
+    }
+    function beforeCursor() {
+        const s = getSelection();
+        const r0 = s.getRangeAt(0);
+        const r = document.createRange();
+        r.selectNodeContents(editor);
+        r.setEnd(r0.startContainer, r0.startOffset);
+        return r.toString();
+    }
+    function afterCursor() {
+        const s = getSelection();
+        const r0 = s.getRangeAt(0);
+        const r = document.createRange();
+        r.selectNodeContents(editor);
+        r.setStart(r0.endContainer, r0.endOffset);
+        return r.toString();
+    }
+    function handleNewLine(event) {
+        if (event.key === 'Enter') {
+            const before = beforeCursor();
+            const after = afterCursor();
+            let [padding] = findPadding(before);
+            let newLinePadding = padding;
+            // If last symbol is "{" ident new line
+            if (options.indentOn.test(before)) {
+                newLinePadding += options.tab;
+            }
+            // Preserve padding
+            if (newLinePadding.length > 0) {
+                preventDefault(event);
+                event.stopPropagation();
+                insert('\n' + newLinePadding);
+            }
+            else {
+                legacyNewLineFix(event);
+            }
+            // Place adjacent "}" on next line
+            if (newLinePadding !== padding && options.moveToNewLine.test(after)) {
+                const pos = save();
+                insert('\n' + padding);
+                restore(pos);
+            }
+        }
+    }
+    function legacyNewLineFix(event) {
+        // Firefox does not support plaintext-only mode
+        // and puts <div><br></div> on Enter. Let's help.
+        if (isLegacy && event.key === 'Enter') {
+            preventDefault(event);
+            event.stopPropagation();
+            if (afterCursor() == '') {
+                insert('\n ');
+                const pos = save();
+                pos.start = --pos.end;
+                restore(pos);
+            }
+            else {
+                insert('\n');
+            }
+        }
+    }
+    function handleSelfClosingCharacters(event) {
+        const open = `([{'"`;
+        const close = `)]}'"`;
+        if (open.includes(event.key)) {
+            preventDefault(event);
+            const pos = save();
+            const wrapText = pos.start == pos.end ? '' : getSelection().toString();
+            const text = event.key + wrapText + close[open.indexOf(event.key)];
+            insert(text);
+            pos.start++;
+            pos.end++;
+            restore(pos);
+        }
+    }
+    function handleTabCharacters(event) {
+        if (event.key === 'Tab') {
+            preventDefault(event);
+            if (event.shiftKey) {
+                const before = beforeCursor();
+                let [padding, start] = findPadding(before);
+                if (padding.length > 0) {
+                    const pos = save();
+                    // Remove full length tab or just remaining padding
+                    const len = Math.min(options.tab.length, padding.length);
+                    restore({ start, end: start + len });
+                    document.execCommand('delete');
+                    pos.start -= len;
+                    pos.end -= len;
+                    restore(pos);
+                }
+            }
+            else {
+                insert(options.tab);
+            }
+        }
+    }
+    function handleUndoRedo(event) {
+        if (isUndo(event)) {
+            preventDefault(event);
+            at--;
+            const record = history[at];
+            if (record) {
+                editor.innerHTML = record.html;
+                restore(record.pos);
+            }
+            if (at < 0)
+                at = 0;
+        }
+        if (isRedo(event)) {
+            preventDefault(event);
+            at++;
+            const record = history[at];
+            if (record) {
+                editor.innerHTML = record.html;
+                restore(record.pos);
+            }
+            if (at >= history.length)
+                at--;
+        }
+    }
+    function recordHistory() {
+        if (!focus)
+            return;
+        const html = editor.innerHTML;
+        const pos = save();
+        const lastRecord = history[at];
+        if (lastRecord) {
+            if (lastRecord.html === html
+                && lastRecord.pos.start === pos.start
+                && lastRecord.pos.end === pos.end)
+                return;
+        }
+        at++;
+        history[at] = { html, pos };
+        history.splice(at + 1);
+        const maxHistory = 300;
+        if (at > maxHistory) {
+            at = maxHistory;
+            history.splice(0, 1);
+        }
+    }
+    function handlePaste(event) {
+        if (event.defaultPrevented)
+            return;
+        preventDefault(event);
+        const originalEvent = event.originalEvent ?? event;
+        const text = originalEvent.clipboardData.getData('text/plain').replace(/\r\n?/g, '\n');
+        const pos = save();
+        insert(text);
+        doHighlight(editor);
+        restore({
+            start: Math.min(pos.start, pos.end) + text.length,
+            end: Math.min(pos.start, pos.end) + text.length,
+            dir: '<-',
+        });
+    }
+    function handleCut(event) {
+        const pos = save();
+        const selection = getSelection();
+        const originalEvent = event.originalEvent ?? event;
+        originalEvent.clipboardData.setData('text/plain', selection.toString());
+        document.execCommand('delete');
+        doHighlight(editor);
+        restore({
+            start: Math.min(pos.start, pos.end),
+            end: Math.min(pos.start, pos.end),
+            dir: '<-',
+        });
+        preventDefault(event);
+    }
+    function visit(editor, visitor) {
+        const queue = [];
+        if (editor.firstChild)
+            queue.push(editor.firstChild);
+        let el = queue.pop();
+        while (el) {
+            if (visitor(el) === 'stop')
+                break;
+            if (el.nextSibling)
+                queue.push(el.nextSibling);
+            if (el.firstChild)
+                queue.push(el.firstChild);
+            el = queue.pop();
+        }
+    }
+    function isCtrl(event) {
+        return event.metaKey || event.ctrlKey;
+    }
+    function isUndo(event) {
+        return isCtrl(event) && !event.shiftKey && getKeyCode(event) === 'Z';
+    }
+    function isRedo(event) {
+        return isCtrl(event) && event.shiftKey && getKeyCode(event) === 'Z';
+    }
+    function isCopy(event) {
+        return isCtrl(event) && getKeyCode(event) === 'C';
+    }
+    function getKeyCode(event) {
+        let key = event.key || event.keyCode || event.which;
+        if (!key)
+            return undefined;
+        return (typeof key === 'string' ? key : String.fromCharCode(key)).toUpperCase();
+    }
+    function insert(text) {
+        text = text
+            .replace(/&/g, '&amp;')
+            .replace(/</g, '&lt;')
+            .replace(/>/g, '&gt;')
+            .replace(/"/g, '&quot;')
+            .replace(/'/g, '&#039;');
+        document.execCommand('insertHTML', false, text);
+    }
+    function debounce(cb, wait) {
+        let timeout = 0;
+        return (...args) => {
+            clearTimeout(timeout);
+            timeout = window.setTimeout(() => cb(...args), wait);
+        };
+    }
+    function findPadding(text) {
+        // Find beginning of previous line.
+        let i = text.length - 1;
+        while (i >= 0 && text[i] !== '\n')
+            i--;
+        i++;
+        // Find padding of the line.
+        let j = i;
+        while (j < text.length && /[ \t]/.test(text[j]))
+            j++;
+        return [text.substring(i, j) || '', i, j];
+    }
+    function toString() {
+        return editor.textContent || '';
+    }
+    function preventDefault(event) {
+        event.preventDefault();
+    }
+    function getSelection() {
+        if (editor.parentNode?.nodeType == Node.DOCUMENT_FRAGMENT_NODE) {
+            return editor.parentNode.getSelection();
+        }
+        return window.getSelection();
+    }
+    return {
+        updateOptions(newOptions) {
+            Object.assign(options, newOptions);
+        },
+        updateCode(code) {
+            editor.textContent = code;
+            doHighlight(editor);
+            onUpdate(code);
+        },
+        onUpdate(callback) {
+            onUpdate = callback;
+        },
+        toString,
+        save,
+        restore,
+        recordHistory,
+        destroy() {
+            for (let [type, fn] of listeners) {
+                editor.removeEventListener(type, fn);
+            }
+        },
+    };
+}