Notch trying jsFiddle

http://jsfiddle.net/uzMPU/

by vasco • 14 years ago

659 134 14 years ago

jsfiddle.net

jeffehobbs• 14 years ago

So cool.

tgandrews2• 14 years ago

Can anyone explain how this works? I never have got to grips with 3D.

tylerdiaz• 14 years ago

Looks like he's ray casting it, no 3D code implemented, just the illusion itself.

antirez9• 14 years ago

Well... actually the code contains a minimal 3D engine, it is not an illusion, you have the observer variable and could use it to navigate inside the map created in the initialization function. What is more 3D than that? :-)

Jare2• 14 years ago

There is no explicit geometry, polygons, or GPU acceleration, but raycasting in 3D is certainly 3D.

DanielRibeiro2• 14 years ago

Update: Thanks for the repliers. You are absolutely right: this is a 3D rendering.

What I meant to say is that it is using Canvas 2D, instead of Canvas 3D, also known as WebGl. Antirez gave a wonderful explanation above[1]:

And indeed it is pretty impressive how fast the rendering happens given that the code operates at such lower level... Even selecting the color of every pixel requires non trivial work in the inner loop

[1] http://news.ycombinator.com/item?id=4862910

tgandrews2• 14 years ago

I appreciate it is written onto a 2d plain. But it does look like 3D. This appearance of looking like 3D when a screen is 2D is complicated and very mathsy (not a word - I know). I've tried reading about it before but it is not straight forward.

chris_p• 14 years ago

In that sense, all games are rendering in 2D, because screens are 2D. They just do it in a much more complicated way.

What I'm seeing in this demo is 3D in every sense, the code is basically a very simple 3D engine, and it requires knowledge of computer graphics to understand it, so the top-level commenter here asked a valid question.

ewolfe• 14 years ago

It looks like he's using a matrix to create cartesian coordinates in a model-view space and then performing some basic linear algebra on the points to animate it. For a primer on 3D worlds check out http://learningwebgl.com/blog/?page_id=1217 where they go over it using WebGL.

antirez9• 14 years ago

Awesome implementation, actually no advanced feature is used, this code could easily ported even to assembler in any device where you can set pixels in RGB format.

AWESOME code.

ukjadoon• 14 years ago

If the creator of Redis approves this, it's definitely awesome! =)

WA2• 14 years ago

I totally agree. You probably meant "code operates at such a _high_ level" :)

low level = close to hardware, high level = high abstraction, like JS

antirez9• 14 years ago

No I really mean low level :-)

Javascript is high level, but here notch is using it as a low level framebuffer.

Jare2• 14 years ago

Indeed, writing straightforward code with no dynamic memory allocations, and simple and predictable types, lets the VM do wonders with optimization and JITting. Good stuff.

jrogers652• 14 years ago

I would argue that this is terrible code. It's not using the appropriate tools (webGL), it's badly structured, uncommented and unmaintainable (seriously, why on earth would anyone name their variables zd, _zd and __zd?). The Minecraft source code is also of notoriously poor quality. I honestly don't understand how you came to your conclusion.

mmcnickle• 14 years ago

The code is a direct port of Minecraft4k[1], it's optimised for space considerations.

[1] https://twitter.com/notch/status/275329867984302081

antirez9• 14 years ago

It's an handful amount of lines of code doing a world generation, texture map generation, and ray casting rendering with a few tricks like a simple lightning model that still looks good.

All this using nothing more than a frame buffer, so you could port this easily from a C64 to any other computer. This code contains a lot of knowledge VS use of pre-build APIs.

If a programmer reads this code and understands how every part works, he or she ends knowing a lot more about computer graphics than before.

experiment02• 14 years ago

Correct me if I'm wrong but does this procedurally generate the textures for each block. I can't see any code for loading assets and the init function, has some quite complicated color code. If so that is awesome!

antirez9• 14 years ago

Yes, the procedure generates the texture of every "type" of block, the first loops after the init() function. 16 different types of blocks are generated.

Then a random map is created, with the "center" that is set to empty blocks with high probability. Finally a function traces the map on the screen at every tick of the clock.

andrewmunsell• 14 years ago

Ok, that's pretty cool :P

scottyallen4• 14 years ago

This would be a great demo to see running in a responsive programming environment, ala Bret Victor's amazing Inventing on Principle talk (http://vimeo.com/36579366). I want to be able to click on hex values and get a color picker that updates the demo in realtime, and be able to click on various magic numbers and drag a slider to change them.

Incidentally, Bret Victor's talk was the starting point for Khan Academy's CS curriculum that John Resign led (http://ejohn.org/blog/introducing-khan-cs/).

Edit: I managed to get this running in livecoding.io, which does some of what Bret Victor was talking about (basic sliders and color pickers): http://livecoding.io/4191583. Not sure why it's running so much slower though...

undergroundhero• 14 years ago

Thanks for the livecoding link. I assume there's some overhead in constantly checking for and applying code changes - that's probably the reason for the lower frame rate.

scottyallen4• 14 years ago

Good point, I hadn't thought about the fact they might be polling for changes. Might be better if livecoding used an event based model to check for updates...

enjalot2• 14 years ago

it's not polling, its reevaluating code when codemirror triggers an event for text changing (which uses the dom underneath).

the problem is from calling setInterval every time the code is evaluated, leading to way too many function calls/second

dsl• 14 years ago

This "responsive programming environment" you speak of has been around for a really long time. Don't expect sliders and colorpickers to do cool stuff, but this should be a good jumping off point for you to start learning from: http://stackoverflow.com/questions/3305164/how-to-modify-mem...

scottyallen4• 14 years ago

Thanks, I'm plenty aware of gdb and debuggers:) (ex-google software engineer, etc etc) Go watch the video. Bret presents a very cogent vision for a dramatic improvement on most of today's standard engineering/design tools.

enjalot2• 14 years ago

Here is a version adapted for Tributary: http://tributary.io/inlet/4199801/

Press play in the bottom left to have it go, and scrub numbers/colors to your hearts content!

Part of the reason it slows down in livecoding is because of the way the original code uses setInterval, and every change reevaluates the code which polutes the scope and starts way too many threads going. I've added optional functionality to Tributary which gives you a run loop (using requestAnimationFrame) that doesn't polute anything.

Hope this helps!

scottyallen4• 14 years ago

Very awesome:) It's _almost_ fast enough to feel like you're modifying it in realtime on my macbook air. This is a great demo of what might be possible with this responsive programming approach.

gbenitez• 14 years ago

I showed it to my mom, and she was like ":Ooohh mother fucker"

JoeCortopassi• 14 years ago

Such a great example of what can be done in javascript/canvas. As it is, I was completely blown away by how little code it actually took to do that. My only gripe would be, why couldn't he have used descriptive variable names, so I can better go through and understand it? :-)

antirez9• 14 years ago

This code uses zero canvas / javascript specific functions. It is using basic trigonometric functions and is using canvas only to write RGB pixels. Canvas are much more powerful and high level than that, but this is not a good example as Notch just needed to set pixels.

petercooper6• 14 years ago

Having watched Notch write Prelude of the Chambered (which I then ported to JRuby) it seems he really loves this direct pixel manipulation style - as do I!

The sad part, though, is it doesn't particularly scale well with canvas (yet) and using sprites, shape primitives, or even WebGL is way to get full speed at a regular resolution. (Imagine a 640x480 pixel field of randomized colors, you can get hundreds of FPS for that in Java without a sweat. Not so in the browser and most certainly not in JRuby.. my PotC port struggled to hit 12fps with equivalent code.)

The title of "ChamberedTest" here makes me wonder if notch is planning to use JS and canvas in the forthcoming Ludum Dare 25 (the gamedev contest where he created Prelude of the Chambered). I hope so!

DanielRibeiro2• 14 years ago

Notch gave a little more context[1]:

Spent most of today learning new stuff. Ported Minecraft4k. Code is awful due to the nature of the project, but here: http://jsdo.it/notch/dB1E

[1] https://twitter.com/notch/status/275329867984302081

cgcardona• 14 years ago

Aren't the following canvas/javascript specific?

ctx = document.getElementById('game').getContext('2d');

pixels = ctx.createImageData(w, h);

ctx.putImageData(pixels, 0, 0);

EDIT: Thanks for the clarification!

joelthelion• 14 years ago

I would never have thought canvas performance would be good enough for this.

tlrobinson• 14 years ago

Reminds me of when I wrote a Game of Life implementation in JavaScript in college using a bunch of tiny absolutely positioned <divs>.

ricardobeat• 14 years ago

"Notch coding in JS" is a bit more descriptive than "trying jsfiddle", specially since it looks like code posted after the fact. A minecraft-like env rendered on canvas with it's own mini-3d-engine is amazing nonetheless :D

felixthehat• 14 years ago

To be fair, that's the description notch used in his tweet: https://twitter.com/notch/status/275331530040160256 :)

citricsquid2• 14 years ago

"Trying jsfiddle.net" was in reference to his previous tweet, the previous host he used crashed under the load from his twitter link. He wasn't "trying jsfiddle.net", he was "trying jsfiddle [as an alternative to the previous host that crashed]"

Pezmc• 14 years ago

Can someone dissect this code and explain what it does?

snprbob86• 14 years ago

The first set of three nested loops is procedurally generating texmap, which is a multidimensional Array(16 * 16 * 3 * 16). 16x16 pixel textures, one for each the top, sides, and bottom, and then 16 of those. The inner loop tests against i, which is the current block "type" and performs customizations to the procedurally generated textures.

The next set of three nested loops is generating a random "world" with a tunnel cut out of it.

The renderMinecraft function is performing a minimal perspective projection http://en.wikipedia.org/wiki/3D_projection for a single ray cast into the world. Each pixel is cast and then, for each object hit by the ray cast, the closest is found, and a texture mapped pixel is calculated and written into the frame buffer.

antirez9• 14 years ago

It is worth to note that lightning model is trivial and only maps given directions of faces to given amount of bright. But other than that the bright is adjusted by distance.

It is pretty cool to see how a trivial lightning model like that can produce a pretty looking result.

If you want to see just the brightness of faces without texture to see more easily how light is used, just change the line:

    var cc = texmap[u + v * 16 + tex * 256 * 3];

Into:

    var cc = 255+(255<<8)+(255<<16);

To also remove the "distant is less bright" effect just add:

    ddist = 255;

Before:

    var r = ((col >> 16) ...

petercooper6• 14 years ago

I've recorded a screencast that digs into how the programmatic texture generation works: https://www.youtube.com/watch?v=WaZvDCmlERc (but I'm not touching the 3D.. yet ;-))

shocks• 14 years ago

    setInterval(clock, 1000 / 100);

Is there any reason for writing 1000/100 instead of 10?

edit: Thanks guys!

estel• 14 years ago

It's a good way to remind you the figure is in ms, and easily manipulate the interval as a fraction of a second.

anatoli• 14 years ago

It just makes it clearer that he wants it to run at 100FPS: (1000ms / desired FPS)

The usefulness is more obvious when you want 60FPS, which is not easily represented without rounding.

dag11• 14 years ago

It was probably for readability, i.e. "100 times per second".

Similarly, people will write (10 * 60 * 60) if the value is seconds and the programmer intends to indicate 10 hours.

Rygu• 14 years ago

100 frames per second. He probably changed that during development.

Riesling• 14 years ago

Probably just to emphasize that clock will be called 100 times per second (which will result in 100 fps).

sisk• 14 years ago

I personal do this for legibility and ease of comprehension. Kinda loses its value when dealing with such nicely rounded numbers but, as an example, 1000ms / 24 is easier or me to comprehend as 24 ticks per second than 41.6666ms.

JungleGymSam2• 14 years ago

Why is the framerate poor even when I shrink the viewing area down 10x10? It seems to have the same stutter as the original large view. Is it because it's doing the same calculations but just showing fewer pixels?

petercooper6• 14 years ago

Yes. It's the calculations and direct pixel setting that's slow, not the actual "rendering" of the canvas (which is accelerated like crazy in most browsers now).

kevingadd2• 14 years ago

Part of the reason it's slow is that it doesn't use typed arrays. This may be much faster for you: http://jsfiddle.net/uzMPU/1573/

voltagex_• 14 years ago

Yes, at least 2x here. I'll pull up Chrome's FPS display later.

Empro• 14 years ago

Interesting, and pretty damn cool!

arriu2• 14 years ago

I enjoy that everything is procedural generated. The software rasterizing is pretty cool too. I don't mind that he uses short variable names, sometimes it's nice to have multiple lines line up perfectly. But this is just silly...

    for ( var x = 0; x < w; x++) {
        var ___xd = (x - w / 2) / h;
        for ( var y = 0; y < h; y++) {
            var __yd = (y - h / 2) / h;
            var __zd = 1;

            var ___zd = __zd * yCos + __yd * ySin;
            var _yd = __yd * yCos - __zd * ySin;

            var _xd = ___xd * xCos + ___zd * xSin;
            var _zd = ___zd * xCos - ___xd * xSin;

albertzeyer• 14 years ago

Can you explain why?

codeka• 14 years ago

I assume because there's four different "xd" variables differing only in the number of underscores prefixed ("xd", "_xd", "__xd" and "___xd"). (Same for "yd" and "zd").

arriu2• 14 years ago

I don't enjoy comparing the length of relatively similar lines. Why not use xa, xb, xc, etc... instead of xd, _xd, __xd, ___xd, yd, _yd, __yd, ___yd, zd, _zd, __zd, ___zd?

petercooper6• 14 years ago

Here's a rendering of the texture map so you can see what it generates directly: http://jsfiddle.net/cXvKa/

gavanwoolery2• 14 years ago

Very cool, but a few notes to anyone getting their hopes up on the powers of Canvas:

As you may have anticipated, this demo runs at less than 1 frame per second on my Nexus 7. :/

In terms of per-pixel manipulation of a Canvas, it is very slow, even with javascript's (not very well supported) typed arrays. Simply put, multidimensional loops (unrolled or not) will always kill performance in JS with any significant dimensions. I learned this the hard way by trying to write a pixel-based GUI, and even that (with some crazy optimizations) could not render fast enough for all devices. If you are just doing blits, Canvas works very well (especially since this operation often uses the GPU).

For now, I think the best option is still WebGL, even though it is not widely supported yet, mobile devices are beginning to pick it up (Blackberry, for example).

hornbaker2• 14 years ago

Runs about 6-7 fps on my iPhone 5.

gavanwoolery2• 14 years ago

Nice :) Shows you how fast ARM is progressing...

AshleysBrain• 14 years ago

While this is cool, isn't this exactly what WebGL is for? I know drivers/support is an issue, but Chrome also ships with a multicore software renderer (SwiftShader) which can probably get a lot further than a JS putImageData engine.

Raticide2• 14 years ago

It's just a demo. It's for fun.

zzzzzzzzz• 14 years ago

Obligatory flash port: http://wonderfl.net/c/sqL5

spyder• 14 years ago

That's faster than the JS demo (even the improved one) in any browser. It's sad that browsers still don't have at least the same performance as flash :(

kevingadd2• 14 years ago

It's faster because he made the Flash version use strongly-typed arrays.

marcamillion• 14 years ago

This shows how far the browser has to go....was it just me, or did your browser start to choke while rendering this?

It rendered it fine, but I could tell that the DOM was being abused heavily. I don't mean that in a bad way, but it just felt very 'heavy'.

On the flip side, this is awesome that the browser can do this - and it's awesome that browsers can do this.

epidemian• 14 years ago

The DOM is not being heavily abused; it's just a canvas element and nothing else. The demo is so CPU intensive because the code is drawing the rasterized image pixel by pixel on the canvas, instead of relying on the GPU and using WebGL which would, AFAIK, result in much better performance.

One positive effect of doing this is that the code is _very_ portable and doesn't require any crazy feature in the browser or the PC (for example, i'm able to see the demo on my work computer even though WebGL doesn't work on it because of lack of drivers).

petercooper6• 14 years ago

I've recorded a screencast that digs into how the programmatic texture generation works in this code: https://www.youtube.com/watch?v=WaZvDCmlERc

unoti• 14 years ago

Enjoyed that immensely, thank you!

terhechte• 14 years ago

Great analysis of whats going on. Thanks.

chii3• 14 years ago

great work.

it'd be also great to do an analysis of the geometry data as well, if you can!

ozataman• 14 years ago

Thanks a lot for taking the time! Any chance you can do one for the game loop and the rest of the code?

seetherage• 14 years ago

who the heck is Notch?

josephagoss• 14 years ago

Notch created a popular pc game called minecraft where you mine blocks and build things. It became very popular and made him a multi-millionaire.

This demo has a little bit of minecraft in it. :)

gyazbek• 14 years ago

thank you very much!

citricsquid2• 14 years ago

http://en.wikipedia.org/wiki/Markus_Persson

http://en.wikipedia.org/wiki/Minecraft

http://en.wikipedia.org/wiki/Mojang

pbhjpbhj• 14 years ago

How is that a bad question. Yes he could have looked it up but it wouldn't have hurt to have "Minecraft creator Notch trying jsFiddle" as the title, would it?

bitteralmond• 14 years ago

Funny how he writes it so much like Java. I see so many different styles with JavaScript.

prawn• 14 years ago

Interesting for an untrained programmer to tweak and see what happens each time - changing colours, speeds, sizes, reversing the flow, changing textures, etc. Accomplishes so much with such concise code.

chii3• 14 years ago

its a good exercise to work out how to stop it from moving "forward" and get the mouse to control the camera. Its a little tricky, but you can do it with about 10-20 more lines of code.

moconnor• 14 years ago

I'm shocked and pleasantly surprised that js/canvas can putpixel fast enough for this. It must be around as fast as assembly on a 486!

Part of me can't decide if that's awesome or tragic.

Flow• 14 years ago

This is actually quite fluid on iPhone 5. I asked a co-worker to try this on his Galaxy S3(quad-core, no lte) and it was really slow there. And in Chrome it was even slower than that on the S3.

Doesn't any web browser on Android use a JIT?

pja• 14 years ago

I believe Firefox for Android does, and as far as I know so does the stock Android browser! Perhaps the pixel writing that Notch is doing is not well optimised on Android?

gps408• 14 years ago

Why is init called twice? Once at the end of the js and then again in the html.

ghenne2• 14 years ago

The one in the html should not be there.

phete• 14 years ago

http://jsfiddle.net/uzMPU/3165/

using window.requestAnimationFrame just because we can!

Aissen• 14 years ago

Wow! This is incredibly smoother here on Firefox 18! (slow machine)

recurser• 14 years ago

Notch has made a couple of comments on reddit :

http://www.reddit.com/r/programming/comments/146v69/how_notc...

    Please do NOT write code like this. It was originally written for the Java4k 
    competition, which focuses on executable code size, and is as a result almost 
    intentionally poorly written. It got even worse when I ported it to JS.
    It was mainly meant as a test for me to see what HTML5/JS can do, and an 
    exercise in porting code over.

http://www.reddit.com/r/programming/comments/146v69/how_notc...

    It would run a bit smoother if it was written in C++ (mainly due to not having 
    to rely on the GC, and having it precompiled gets rid of the warmup time), and 
    modern OpenGL would help quite a lot as well. A lot of the stuff done in CPU 
    now could be moved to a shader, which both makes code simpler, and gets rid of 
    the slow JNI calls required now.
    The main reason why Minecraft is slow is mainly 1) There's a LOT of polygons, 
    combined with 2) The difficulty of making an efficient culling algorithm in a 
    dynamic world.
    If someone solves #2, very interesting things could be made with a game similar 
    to Minecraft.

http://www.reddit.com/r/programming/comments/146v69/how_notc...

    No, they don't get merged because the textures are all pulled from the same atlas 
    to avoid texture swapping. With GLSL, they could be merged, saving quite a lot of 
    polygons. For a while, I did attempt switching the atlas from a 16 x 16 grid to a 
    1 x 256 grid and merging horizontal runs of the same texture, but the resulting 
    texture size was to tall some graphics cards (on low end computers) would 
    automatically downsample it.
    The problem with the occlusion culling is not about knowing what parts are static, 
    but rather figuring out what occluders there are. It would be very beneficial not 
    to have to render caves under ground below the player, for example, or not to 
    render the entire outside when a player is inside a small closed house. Figuring 
    this out in runtime on the fly as the player moves around is.. expensive.

ghenne2• 14 years ago

Here is the code in an App Studio project:

http://blog.nsbasic.com/?p=1060

Runs fine on an iPhone 5!

HyprMusic2• 14 years ago

There's been quite a bit of analysis as to what's happening here, if anyone could do a breakdown (or provide good examples) it would be awesome for people like me who are amazed by the power of the maths involved here.

malkia2• 14 years ago

Almost straight port here to luajit - http://github.com/malkia/ufo/blob/master/samples/notch.lua

p01• 14 years ago

Tooting my own horn here, but here's my own little "Minecraft" renderer in Neja, circa 2005 ( http://www.youtube.com/watch?feature=player_detailpage&v... ). Over 4 years before Minecraft, and even then that was nothing new. It was kinda cool for JavaScript, in 2005, but all things considered, it was pretty lame compared to Ken Silverman's voxlap for instance.

The "cool" thing about this demo, was that Canvas was not widespread back then so I generated all the chunky effects on the fly as 24bits BMP image, then made a data: URI and update an IMG tag.

Notch trying jsFiddle

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