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conclusion of tairu

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liquidex 2024-02-19 22:32:26 +01:00
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25
content/about-treehouse/emoji.tree
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@ -1,3 +1,5 @@
%% title = "Graphical Indicators of Emotion, more commonly known as \"emoticons\" or under the brand name \"Emoji\""
% id = "01H8W7VEVNQ0XR4RDYRGMKS0E9"
- the emojis here are grouped by game, topic, or other thing for easier navigation
@ -67,13 +69,36 @@
% id = "01H8W7VEVPSHDWDH58HFKBMGD6"
- but I don't wanna replace it because it's just too good
% id = "emoji/nap"
- :nap: - <sub>z</sub>zZ
% id = "01HQ162WWF60BD1F4K26E7ZZEV"
- ### random places
% id = "emoji/ahyes"
- :ahyes: - ah, yes
% id = "01HQ162WWFYWW92J0DKRWNZYDY"
- smuggest expression for the smuggest of moments, and some tea with it.
% id = "emoji/kamien"
- :kamien: - stone cold
% id = "01HQ1K39AYJ2KEFFDAM6A8M8ET"
- Polish for _rock_ (stone, not the music genre)
% id = "01HQ1K39AY808NPR08YPBAR1ZF"
+ an expression of magnificence in primitivity
% id = "01HQ1K39AYKA86GRF12PFDN96N"
+ or magnificence in stupidity
% id = "01HQ1K39AYPE9FCD1FR93H60RR"
+ or being dead fucking serious about not liking something that's either of the two above (non-exclusive OR)
% id = "01HQ1K39AYM2FS3R4Y9175V7XS"
- all credit goes to Apple for designing this beauty
% id = "01HA4HJKQ7FKV8JJ70Q2CY9R86"
- ### [Noto Color Emoji](https://github.com/googlefonts/noto-emoji/)

382
content/programming/blog/tairu.tree
View file

@ -15,8 +15,9 @@ styles = ["tairu.css"]
- TODO: short videos demoing this here
% id = "01HPD4XQPWJBTJ4DWAQE3J87C9"
- once upon a time I stumbled upon a technique called...
- once upon a time I stumbled upon a technique called…
% id = "01HQ162WWA1KXZPBDWJXSCQA1D"
- ### bitwise autotiling
% id = "01HPD4XQPW6VK3FDW5QRCE6HSS"
@ -25,6 +26,7 @@ styles = ["tairu.css"]
% id = "01HPD4XQPWJ1CE9ZVRW98X7HE6"
- Construct 2 was one of my first programming experiences and the first game engine I truly actually liked :smile:
% id = "01HQ162WWAMCPC5M88QAXHX4BT"
- so to help us learn, I made a little tile editor so that we can experiment with rendering tiles! have a look:
```javascript tairu
@ -48,6 +50,7 @@ styles = ["tairu.css"]
```output tairu
```
% id = "01HQ162WWAC3FN565QE3JAB87D"
- `Tilemap` is a class wrapping a flat [`Uint8Array`] with a `width` and a `height`, so that we can index it using (x, y) coordinates.
```javascript tairu
@ -59,31 +62,42 @@ styles = ["tairu.css"]
[`Uint8Array`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
% id = "01HQ162WWA090YW5BR1XW68XJN"
- `at` has a `setAt` counterpart which sets tiles instead of getting them.
% id = "01HQ162WWAMD68SY56P7TVT2DJ"
- `TileEditor` provides a graphical editor for a `Tilemap` based on a `<canvas>`.
% id = "01HQ162WWABTFQ0J83C4VZYZB5"
- this editor is _Certified Battery Efficient™_, so it won't redraw unless it needs to!\
we'll need to keep this in mind for later when we try to draw images, which may not be loaded during the initial draw.
% id = "01HQ162WWA8Y1AD22MSN71V2E4"
- to kick this off, let's set off a goal. I would like the tiles in our little renderer to connect together, like this:
![red rectangle with a black outline, made out of 3x3 tiles][pic:01HPYW5SNTY0Z0ENDE5K3XWMTH]
% id = "01HQ162WWAZV559ABQD1NVXPMA"
- let's break this down into smaller steps. drawing a border around the rectangle will involve:
% id = "01HQ162WWATV30HXGBQVWERP2M"
- determining *on which tiles* to draw it,
% id = "01HQ162WWAA0V0SS0D1Y38BDS1"
- determining *where in these tiles* to draw it,
% id = "01HQ162WWAGBCBDYF4VH26MX1B"
- and actually drawing it!
% id = "01HQ162WWA2PNGVV075HR3WMER"
- so let's zoom in a bit and look at the tiles one by one. in particular, let's focus on *these* two tiles:
![the same red rectangle, now with a focus on the northern tile at its center][pic:01HPYWPJB1P0GK53BSJFJFRAGR]
% id = "01HQ162WWAYDS6CSD3T102NA9X"
- notice how the two highlighted tiles are *different.* therefore, we can infer we should probably connect together any tiles that are *the same*.
% id = "01HQ162WWATDD86D4GY7RMT0BZ"
- knowing that, we can extract the logic to a function:
```javascript tairu
@ -92,19 +106,24 @@ styles = ["tairu.css"]
}
```
% id = "01HQ162WWA9M6801Q0RNRSF09H"
+ now, also note that the border around this particular tile is only drawn on its *northern* edge -
therefore we can infer that borders should only be drawn on edges for whom `shouldConnect(thisTile, adjacentTile)` is **`false`** (not `true`!).
a tile generally has four edges - east, south, west, north - so we need to perform this check for all of them, and draw our border accordingly.
% id = "01HQ162WWAM5YYQCEXH791T0E9"
- you might be wondering why I'm using this particular order for cardinal directions - why not [north, south, east, west]? or [north, east, south, west]?
% id = "01HQ162WWABJ696HCJ09WDC0NX"
- the reason comes from math - `[cos(0) sin(0)]` is a vector pointing rightwards, not upwards!
and I chose clockwise order, because that's how the vector rotates as we increase the angle, in a coordinate space where +Y points downward - such as the `<canvas>` coordinate space.
% id = "01HQ162WWABNXV4N2AHZBQC5B7"
- this choice yields some nice orderliness in the code that handles fetching tiles for connections - first you check `+X`, then `+Y`, then `-X`, and then `-Y` -
which my pedantic mind really appreciates :ahyes:\
as `X` is first alphabetically, so checking `Y` first would feel wrong.
% id = "01HQ162WWA5W8NXSXVZY3BBQ0H"
- to do that, I'm gonna override the tile editor's `drawTilemap` function - as this is where the actual tilemap rendering happens!
```javascript tairu
@ -173,13 +192,16 @@ styles = ["tairu.css"]
```output tairu
```
- this looks pretty perfect - maybe sans corners, which I'll conveniently skip for now - because most games don't actually render graphics in a vectorial way like this!
% id = "01HQ162WWAAEKW1ECV5G3ZEY47"
- this looks pretty perfect - maybe sans corners, which I'll conveniently skip for now, because most games don't actually render graphics in a vectorial way like this!
instead, the more common way is to use a tileset - a big texture with a bunch of sprites to use for rendering each tile.
% id = "01HQ162WWACD5CD7GCZE53ZPD7"
- not only does this have the advantage of allowing for richer graphics, but it is also a lot easier to modify by artists, because you no longer need knowledge of graphics APIs to draw tiles.
% template = true
classes.branch = "tileset-cardinal-directions-demo"
id = "01HQ162WWAADKPDQE69W3QZG0M"
- for example, here's a tileset I drew for the 3rd iteration of my game [Planet Overgamma] - though tweaked a bit because I had never used it before writing this post :hueh:
![heavy metal sheet tileset from Planet Overgamma, made out of 16 tiles. it looks like heavy embossed sheets of metal, resembling steel in its heavyness][pic:01HPHVDRV0F0251MD0A2EG66C4]
@ -187,6 +209,7 @@ styles = ["tairu.css"]
[Planet Overgamma]: https://github.com/liquidev/planet-overgamma
% classes.branch = "tileset-cardinal-directions-demo"
id = "01HQ162WWAS502000K8QZWVBDW"
- we can split this tileset up into 16 individual tiles, each one 8 × 8 pixels; people choose various resolutions, I chose a fairly low one to hide my lack of artistic skill.
<div class="horizontal-tile-strip">
@ -209,6 +232,7 @@ styles = ["tairu.css"]
</div>
% classes.branch = "tileset-cardinal-directions-demo"
id = "01HQ162WWANBTYH1JJWCTZYYVN"
- the keen eyed among you have probably noticed that this is very similar to the case we had before with drawing procedural borders -
except that instead of determining which borders to draw based on a tile's neighbors, this time we'll determine which *whole tile* to draw based on its neighbors!
@ -231,15 +255,20 @@ styles = ["tairu.css"]
<span class="metal x-3 y-3"></span>
</div>
% id = "01HQ162WWA4Z6KKWFV59BR4WD3"
- previously we represented which single border to draw with a single boolean.
now we will represent which single tile to draw with *four* booleans, because each tile can connect to four different directions.
% id = "01HQ162WWAQ9GZ6JD8KESW4N53"
- four booleans like this can easily be packed into a single integer using some bitwise operations, hence we get ***bitwise autotiling*** - autotiling using bitwise operations!
% id = "01HQ162WWAMBM8RXKQTN3D0XR2"
- now the clever part of bitwise autotiling is that we can use this packed integer *as an array index* - therefore selecting which tile to draw can be determined using just a single lookup table! neat, huh?
% id = "01HQ162WWA0ZGZ97JZZBFS41TF"
- but because I'm lazy, and CPU time is valuable, instead of using an array I'll just rearrange the tileset texture a bit to be able to slice it in place using this index.
% id = "01HQ162WWAQQ99TRBDY5DCSW3Z"
- say we arrange our bits like this:
```javascript tairu
@ -250,6 +279,7 @@ styles = ["tairu.css"]
```
% classes.branch = "tileset-cardinal-directions-demo"
id = "01HQ162WWABANND0WGT933TBMV"
- that means we'll need to arrange our tiles like so, where the leftmost tile is at index 0 (`0b0000`) and the rightmost tile is at index 15 (`0b1111`):
<div class="horizontal-tile-strip">
@ -271,16 +301,21 @@ styles = ["tairu.css"]
<span class="metal x-1 y-1"><span class="east">E</span><span class="south">S</span><span class="west">W</span><span class="north">N</span></span>
</div>
% id = "01HQ162WWAJPW00XA25N0K6KS7"
- packing that into a single tileset, or rather this time, a *tile strip*, we get this image:
![horizontal tile strip of 16 8x8 pixel metal tiles][pic:01HPMMR6DGKYTPZ9CK0WQWKNX5]
% id = "01HQ162WWAT2ZC7T2P9ATD6WG2"
- now it's time to actually implement it as code! I'll start by defining a *tile index* function as a general way of looking up tiles in a tileset.
% id = "01HQ162WWA0NRHBB6HP2RERNBK"
- I want to make the tile renderer a bit more general, so being able to attach a different tile lookup function to each tileset sounds like a great feature.
% id = "01HQ162WWA9PGSHH5E97RVE1PB"
- just imagine some game where glass connects to metal, but metal doesn't connect to glass - I bet that would look pretty great!
% id = "01HQ162WWAYJ4JCG3Z24SJR8S9"
- …but anyways, here's the basic bitwise magic function:
```javascript tairu
@ -298,12 +333,13 @@ styles = ["tairu.css"]
```
% template = true
id = "01HQ162WWAS813ANMBG1PWDZHC"
- we'll define our tilesets by their texture, tile size, and a tile indexing function. so let's create an object that will hold our tileset data:
```javascript tairu
// You'll probably want to host the assets on your own website rather than
// hotlinking to others. It helps longevity!
const tilesetImage = new Image();
let tilesetImage = new Image();
tilesetImage.src = "{% pic 01HPMMR6DGKYTPZ9CK0WQWKNX5 %}";
export const heavyMetalTileset = {
@ -313,6 +349,7 @@ styles = ["tairu.css"]
};
```
% id = "01HQ162WWA0SC2GA7Y3KJE0W5F"
- with all that, we should now be able to write a tile renderer which can handle textures! so let's try it:
```javascript tairu
@ -360,7 +397,8 @@ styles = ["tairu.css"]
}
```
- drum roll please...
% id = "01HQ162WWAS2HYF41MZNJ18BXC"
- drum roll please…
```javascript tairu
new TilesetTileEditor({
@ -372,6 +410,7 @@ styles = ["tairu.css"]
```output tairu
```
% id = "01HQ162WWA03JAGJYCT0DRZP24"
- it works! buuuut if you play around with it you'll quickly start noticing some problems:
```javascript tairu
@ -393,58 +432,75 @@ styles = ["tairu.css"]
```output tairu
```
% id = "01HQ162WWAB0AYSPGB4AEVT03Z"
- where did our nice seamless connections go!?
% template = true
id = "01HPMVT9BM9CS9375MX4H9WKW8"
- and that gives us this result:
% id = "01HQ162WWA3Q095ZGXDFZ1V2Q1"
- ### thing is, it was never good in the first place
<canvas
is="tairu-editor"
data-tilemap-id="bitwiseAutotiling"
data-tile-size="40"
>
Your browser does not support &lt;canvas&gt;.
<img class="resource" src="{% pic 01HPMMR6DGKYTPZ9CK0WQWKNX5 %}" data-tairu-tileset="1">
</canvas>
% id = "01HQ162WWARSVDRNHZE13ZF6W6"
- I'll be blunt: we don't have enough tiles to represent *corners*! like in this case:
% id = "01HPMVT9BM3WR0BNZFHP2BPZ8A"
- but if you play around with it (or have *already* played around with it, and are therefore left with a non-default tilemap)
```javacript tairu
import { Tilemap } from "tairu/tilemap.js";
...something seems awful about it doesn't it?
new TilesetTileEditor({
tilemap: Tilemap.parse(" x", [
" ",
" xx ",
" x ",
" ",
]),
tileSize: 40,
tilesets: [heavyMetalTileset],
});
```
```output tairu
```
% template = true
id = "01HPMVT9BMPA89037VPWPPWX8V"
- something's off about the corners. let me give you a fresh example to illustrate what I mean:
% id = "01HQ1K39AS4VDW7DVTAGQ03WFM"
- have a closer look at the top-left tile:
<canvas
is="tairu-editor"
data-tilemap-id="bitwiseAutotilingChapter2"
data-tile-size="40"
>
Your browser does not support &lt;canvas&gt;.
<img class="resource" src="{% pic 01HPMMR6DGKYTPZ9CK0WQWKNX5 %}" data-tairu-tileset="1">
</canvas>
![the above example, showing an L shape rotated 180°, with the top left corner highlighted][pic:01HQ167GJEPTKHAKAVNW3WN1SZ]
% id = "01HPMVT9BM16EF3TV5J1K19JAM"
+ see that tile in the bottom left corner of the `L` shape? it's missing a corner.
the top-right corner, to be exact, which makes it visually disjoint from the tiles to the north and the east.
% id = "01HQ1K39AS6Y9XMJTMMQYTWRMC"
- it should kind of _"bend"_ to fit in with the tiles to the north and the south, but it doesn't :kamien:
% id = "01HPMVT9BM5VWJSMDNPK2SRNZV"
- (I'm totally not trying to say this implementation is an L so far)
% id = "01HQ1K39ASQQNF7B881SYJWRC7"
- so what if we made the tile look like *this* instead:
% 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!
![mockup showing that previous L-shape but with a real corner][pic:01HQ17GYEZSZCVRBFHP4HXAJV8]
% id = "01HPMVT9BMQK8N1H68YV3J4CFQ"
- see what I did there?
% id = "01HQ1K39ASMKRMTXFV93FRHZTG"
- that sure as heck looks a lot nicer! but there's a problem: that tile, let's zoom in on it…
% id = "01HPMVT9BMJTG3KD3K5EJ3BC93"
- the solution to that is to introduce more tiles to handle these edge cases.
![that bent tile, and just *it* alone][pic:01HQ183RANGH4S7VZSG1ZGH0S5]
% classes.branch = "tileset-four-to-eight-demo"
id = "01HQ1K39ASR81NWMW8Q0MF8QMP"
- enhance!
<ul class="directions-square bend">
<li class="east">E</li>
<li class="south">S</li>
</ul>
% classes.branch = "tileset-four-to-eight-demo"
id = "01HQ1K39ASC5WTR2A2AJN85JK2"
- huh. interesting. it connects to the east and the south. so what about this tile -
<ul class="directions-square e-s">
<li class="east">E</li>
<li class="south">S</li>
</ul>
% id = "01HQ1K39ASXYBH9QJH5Q0C45JZ"
- because it *also* connects to the east and the south :thinking:
% id = "01HQ1K39ASW5PWS52NGA2X3M0P"
- seems like we'll need something to disambiguate the two cases - and what better thing to disambiguate with than *more bits*!
% classes.branch = "tileset-four-to-eight-demo"
id = "01HPQCCV4R5N97FJ1GS36HZJZ7"
- to represent the corners, we'll turn our four cardinal directions...
- to represent the corners, we'll turn our four cardinal directions…
<ul class="directions-square">
<li class="east">E</li>
@ -466,32 +522,43 @@ styles = ["tairu.css"]
<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...
% id = "01HQ1K39ASFN94YDY1RWQYS12K"
- at this point with the four extra corners 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:
id = "01HQ1K39AS11M1M4GQQ60NXTY6"
- …right! let's stick with the 16 tile version for a moment.
if we arrange the tiles in a diagnonal cross like this, notice how the tile in the center would have the bits `SE | SW | NW | NE` set, which upon first glance would suggest us needing a different tile -
but it looks correct!
<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>
```javascript tairu
import { Tilemap } from "tairu/tilemap.js";
these should all render the same way, despite technically having some [new neighbors](https://en.wikipedia.org/wiki/Moore_neighborhood).
new TilesetTileEditor({
tilemap: Tilemap.parse(" x", [
" ",
" x x ",
" x ",
" x x ",
" ",
]),
tileSize: 40,
tilesets: [heavyMetalTileset],
});
```
```output tairu
```
% id = "01HQ1K39AS7CRBZ67N1VVHCVME"
- therefore there must be *some* bit combinations that are redundant to others. let's find them!
% 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`:
id = "01HQ1K39ASZPJ4E23EZ1XJ5J7K"
- let's pick one corner first, then generalize to all the other ones. I pick southeast!
<ul class="directions-square e-s">
<li class="east">E</li>
@ -499,15 +566,44 @@ styles = ["tairu.css"]
<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 = "01HQ1K39ASQTR054W0VWEAV2FS"
- in this case, if we remove the tile to the southeast, we get that bent tile from before:
<ul class="directions-square bend">
<li class="east">E</li>
<li class="south">S</li>
</ul>
% id = "01HQ1K39AS6RGE6Z83T8MH1R0M"
- what we can learn from this is that for `E | S`, `ES` affects the result!
% id = "01HQ1K39ASVSAQ6F8ANEZE1WQ4"
- but if we add any other corner, nothing changes. heck, let's add all of them:
<ul class="directions-square e-s">
<li class="east">E</li>
<li class="south-east">SE</li>
<li class="south">S</li>
<li class="south-west">SW</li>
<li class="north-west">NW</li>
<li class="north-east">NE</li>
</ul>
% id = "01HQ1K39AST8RQTVSCDV7FSH62"
- this combination is definitely redundant!
% id = "01HQ1K39AS8VHKHANJFKA4PQJ5"
- so it seems like for any two cardinal directions such as `E` and `S`, the ordinal direction that's a combination of the two -
in this case `ES` - only matters if both the cardinal direction bits are set!
% 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.
% id = "01HPSY4Y19NQ6DZN10BP1KQEZN"
+ we'll start off by defining a bunch of variables to represent our ordinal directions:
+ we'll start off by redefining our bits to be ordinal directions instead. I still want to keep the [nice orderliness][branch:01HQ162WWAM5YYQCEXH791T0E9] that comes with
arranging the bits clockwise starting from east, so if we want that we can't just extend the indices with an extra four bits at the top.
```javascript ordinal-directions
```javascript tairu
export const E = 0b0000_0001;
export const SE = 0b0000_0010;
export const S = 0b0000_0100;
@ -516,18 +612,12 @@ styles = ["tairu.css"]
export const NW = 0b0010_0000;
export const N = 0b0100_0000;
export const NE = 0b1000_0000;
export const ALL = E | SE | S | SW | W | NW | N | NE;
```
as I've already said, we represent each direction using a single bit.
% id = "01HPSY4Y19AW70YX8PPA7AS4DH"
- I'm using JavaScript by the way, because it's the native programming language of your web browser. read on to see why.
% id = "01HPSY4Y19HPNXC54VP6TFFHXN"
- 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:
- 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
```javascript tairu
export function isSet(integer, bit) {
return (integer & bit) == bit;
}
@ -537,8 +627,8 @@ styles = ["tairu.css"]
- 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
```javascript tairu
// t is an existing tile index; variable name is short for brevity
export function removeRedundancies(t) {
if (isSet(t, SE) && (!isSet(t, S) || !isSet(t, E))) {
t &= ~SE;
@ -559,10 +649,10 @@ styles = ["tairu.css"]
% id = "01HPSY4Y19HWQQ9XBW1DDGW68T"
- with that, we can find a set of all unique non-redundant combinations:
```javascript ordinal-directions
```javascript tairu
export function ordinalDirections() {
let unique = new Set();
for (let i = 0; i <= ALL; ++i) {
for (let i = 0; i <= 0b1111_1111; ++i) {
unique.add(removeRedundancies(i));
}
return Array.from(unique).sort((a, b) => a - b);
@ -576,14 +666,14 @@ styles = ["tairu.css"]
[`Array.prototype.sort`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort
% id = "01HPSY4Y19V62YKTGK3TTKEB38"
- and now it's time to _Let It Cook™_:
- and with all the ingredients in the pot, we now _Let It Cook™_:
```javascript ordinal-directions
```javascript tairu
let dirs = ordinalDirections();
console.log(dirs.length);
```
```output ordinal-directions
```output tairu
47
```
@ -595,7 +685,7 @@ styles = ["tairu.css"]
the forty eighth tile is actually just the empty tile! saying it's part of the tileset is quite misleading IMO.
% id = "01HPSY4Y19TM2K2WN06HHEM3D0"
- phew... the nesting's getting quite unwieldy, let's wrap up this tangent and return back to doing some bitwise autotiling!
- phew… the nesting's getting quite unwieldy, let's wrap up this tangent and return back to doing some bitwise autotiling!
% id = "01HPSY4Y192FZ37K3KXZM90K9J"
- 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!
@ -613,38 +703,40 @@ styles = ["tairu.css"]
% id = "01HPWJB4Y0HKGSDABB56CNFP9H"
- think that with this redundancy elimination approach most of the tiles will never even be looked up by the renderer, because the bit combinations will be collapsed into a more canonical form before the lookup.
% id = "01HPWJB4Y0705RWPFB89V23M1P"
- we could also use the approach I mentioned briefly [here][branch:01HPQCCV4RB65D5Q4RANJKGC0D], which involves introducing a lookup table - which sounds reasonable, so let's do it!
% id = "01HQ1K39ASM53P1E74HKRZ1T24"
- so instead of wasting space, we can compress the tiles into a compact strip, and use a lookup table from sparse tile indices to dense tile *positions* within the strip.
% id = "01HPWJB4Y0F9JGXQDAAVC3ERG1"
- I don't want to write the lookup table by hand, so let's generate it! I'll reuse the redundancy elimination code from before to make this easier.
- I don't want to write the lookup table by hand, so let's generate it!
% id = "01HPWJB4Y0HTV32T4WMKCKWTVA"
- we'll start by obtaining our ordinal directions array again:
```javascript ordinal-directions
```javascript tairu
export let xToConnectionBitSet = ordinalDirections();
```
% id = "01HPWJB4Y03WYYZ3VTW27GP7Z3"
- then we'll turn that array upside down... in other words, invert the index-value relationship, so that we can look up which X position in the tile strip to use for a specific connection combination.
- then we'll turn that array upside down… in other words, invert the index-value relationship, so that we can look up which X position in the tile strip to use for a specific connection combination.
remember that our array has only 256 values, so it should be pretty cheap to represent using a `Uint8Array`:
remember that our array has only 256 values, so it should be pretty cheap to represent using a [`Uint8Array`]:
```javascript ordinal-directions
```javascript tairu
export let connectionBitSetToX = new Uint8Array(256);
for (let i = 0; i < xToConnectionBitSet.length; ++i) {
connectionBitSetToX[xToConnectionBitSet[i]] = i;
}
```
[`Uint8Array`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
% id = "01HPWJB4Y0CWQB9EZG6C91A0H0"
- and there we go! we now have a mapping from our bitset to positions within the tile strip. try to play around with the code example to see which bitsets correspond to which position!
```javascript ordinal-directions
```javascript tairu
console.log(connectionBitSetToX[E | SE | S]);
```
```output ordinal-directions
```output tairu
4
```
@ -652,7 +744,7 @@ styles = ["tairu.css"]
+ for my own (and your) convenience, here's a complete list of *all* the possible combinations in order.
% id = "01HPWJB4Y01VJFMHYEC1WZ353W"
- ```javascript ordinal-directions
- ```javascript tairu
function toString(bitset) {
if (bitset == 0) return "0";
@ -672,7 +764,7 @@ styles = ["tairu.css"]
console.log(`${x} => ${toString(xToConnectionBitSet[x])}`);
}
```
```output ordinal-directions
```output tairu
0 => 0
1 => E
2 => S
@ -730,36 +822,108 @@ styles = ["tairu.css"]
![horizontal tile strip of 47 8x8 pixel metal tiles][pic:01HPW47SHMSVAH7C0JR9HWXWCM]
% id = "01HPWJB4Y0J3DHQV5F9GD3VNQ8"
- now let's hook it up to our tileset renderer! TODO literate program.
- now let's hook it up to our tileset renderer!
% id = "01HQ1M84GS09M7PMXFYHDPRTMT"
- since we already prepared the bulk of the framework before, it should be as simple as writing a new `tileIndex` function:
```javascript tairu
export function tileIndexInBitwiseTileset47(tilemap, x, y) {
let tile = tilemap.at(x, y);
let tileBitset = 0;
tileBitset |= shouldConnect(tile, tilemap.at(x + 1, y)) ? E : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x + 1, y + 1)) ? SE : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x, y + 1)) ? S : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x - 1, y + 1)) ? SW : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x - 1, y)) ? W : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x - 1, y - 1)) ? NW : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x, y - 1)) ? N : 0;
tileBitset |= shouldConnect(tile, tilemap.at(x + 1, y - 1)) ? NE : 0;
return connectionBitSetToX[removeRedundancies(tileBitset)];
}
```
% template = true
id = "01HPWJB4Y00ARHBGDF2HTQQ4SD"
- with the capability to render with 47-tile tilesets, our examples suddenly look a whole lot better!
id = "01HQ1M84GS4C99VQZC4150CMDS"
- now we can write a new tileset descriptor that uses this indexing function and the larger tile strip:
```javascript tairu
// Once again, use your own link here!
let tilesetImage = new Image();
tilesetImage.src = "{% pic 01HPW47SHMSVAH7C0JR9HWXWCM %}";
export const heavyMetalTileset47 = {
image: tilesetImage,
tileSize: 8,
tileIndex: tileIndexInBitwiseTileset47,
};
```
% id = "01HQ1M84GS9CC8VR1BVDC15W50"
- and Drum Roll 2: Return of the Snare please…
```javascript tairu
import { Tilemap } from "tairu/tilemap.js";
new TilesetTileEditor({
tilemap: Tilemap.parse(" x", [
" x ",
" x x ",
" xxx ",
" xx ",
" x ",
]),
tileSize: 40,
tilesets: [heavyMetalTileset47],
});
```
```output tairu
```
% id = "01HQ1M84GSCXTPGVPXY840WCQ6"
- it works perfectly!
% id = "01HQ1M84GSVBG9T94ZN9XTXX58"
- but honestly, this is a bit *boring* if we're gonna build a game with procedural worlds.
% id = "01HQ1M84GSH0KTFFZET6GZZ4V2"
- heck, it's even boring for a level designer to have to lay out all the tiles manually -
introducing variations and what not, such that the world doesn't look too bland… there has to be a better way!
% id = "01HQ1M84GSE1N5WG88DGJZH0F8"
- and a better way… there is! but I'll get to that once my nap is over. <!--
% id = "01HQ1M84GS0KJ9NA6GPS62RC95"
- for now, have a big editor to play around with. it's a lot of fun arranging the tiles in various shapes!
```javascript tairu
import { Tilemap } from "tairu/tilemap.js";
new TilesetTileEditor({
tilemap: new Tilemap(25, 16),
tileSize: 40,
tilesets: [heavyMetalTileset47],
});
```
```output tairu
```
:nap:
% disabled = true
id = "01HQ1M84GS3WKE2X6QV2SNQX46"
- TODO: next chapter! if you're reading this, you're in on it soon. that's quite sad, but YOU CAN STILL TURN BACK! I advise you to do that immediately.
You have been warned.
<canvas
is="tairu-editor"
data-tilemap-id="bitwiseAutotiling47"
data-tile-size="40"
>
Your browser does not support &lt;canvas&gt;.
<img class="resource" src="{% pic 01HPW47SHMSVAH7C0JR9HWXWCM %}" data-tairu-tileset-47="1">
</canvas>
% id = "01HPD4XQPWT9N8X9BD9GKWD78F"
- 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 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
[Planet Overgamma]: https://liquidev.itch.io/planet-overgamma-classic
% id = "01HPJ8GHDEN4XRPT1AJ1BTNTFJ"
- this accursed game has been haunting me for years since; there have been many iterations.
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
% id = "01HPD4XQPWPN6HNA6M6EH507C6"
+ but one day I found a really cool project called [Tilekit](https://rxi.itch.io/tilekit)
@ -811,7 +975,7 @@ styles = ["tairu.css"]
- then vines
% id = "01HPSY4Y19FA2HGYE4F3Y9NJ57"
- well... it's even simpler than that in terms of graphical presentation, but we'll get to that.
- 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?

8
static/css/main.css
View file

@ -303,6 +303,11 @@ img {
/* TODO: These could be autogenerated! */
&[src*='+width72'] {
width: 72px;
height: auto;
}
&[src*='+width160'] {
width: 160px;
height: auto;
@ -556,6 +561,7 @@ th-literate-program[data-mode="output"] {
padding: 0;
background: none;
border: none;
border-radius: 0;
& iframe {
border-style: none;
@ -635,7 +641,7 @@ th-literate-program[data-mode="output"] {
--syntax-comment: #aca8a4;
--syntax-identifier: var(--text-color);
--syntax-keyword1: #ffb06a;
--syntax-keyword2: #9acfe3;
--syntax-keyword2: #8ad4f9;
--syntax-operator: #ec9f8d;
--syntax-function: #fbd283;
--syntax-literal: #e9b9f0;

14
static/css/tairu.css
View file

@ -135,6 +135,20 @@
position: relative;
&.bend {
background-image: url('../pic/01HQ183RANGH4S7VZSG1ZGH0S5-the-tile+width72+pixel.png');
background-size: 100%;
background-position: 0 0;
background-repeat: no-repeat;
}
&.notabend {
background-image: url('../pic/01HQ18E39K5F9Q5P41XAEVSEWK-the-also-tile.png');
background-size: 100%;
background-position: 0 0;
background-repeat: no-repeat;
}
li {
padding: 2px 4px;
position: absolute;

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