Bootable Minecraft clone written partly in x86 Assembly

by charliesome • 13 years ago

285 47 13 years ago

angersock• 13 years ago

I love that the author decided (if my interpretation is correct) "Writing a software rasterizer is annoying...fuck it, let's use a raytracer." Very nice!

blt• 13 years ago

Ray tracing is easier to implement than rasterization...

joakleaf• 13 years ago

It really depends on how much functionality you want for both methods.

Rasterization really doesn't require that much work, but you need to be able to do a world/view-transform, clip triangles/quads, and do perspective correct texturing. The most sophisticated bit of that is a clipping algorithm, which is really easy to implement.

Ray tracing requires you to generate a ray per pixel (essentially the opposite world/view-transform), determine ray/box intersections, and based on the intersection coordinate of ray and box determine a texture coordinate.

As someone who has done both, I would say the two procedures are pretty the same level of complexity (if you stay away from bilinear texture interpolation), but I admit that raytracing feels easier to implement as you avoid the clipping and perspective correct texturing.

However, The Minecraft world is a uniform grid of "boxes", so it contains a lot of quads leading to potentially huge amounts of overdraw which quickly becomes infeasible for a software-rasterizer. So if you wish to rasterize in software, you'll need to do a bit of additional work to avoid drawing a lot of hidden box-sides (ignore shared sides), and you'll never get overdraw down to 0 unless you use additional screen-based data-structures.

On the other hand, the author had to implement a raycasting algorithm on the uniform grid for the raytracer to be efficient. This is actually also a little bit painful.

So for that reason, the ray-tracer is definitely the right decision here.

On a related note, I tried to implement raycasting on a uniform 3D grid on a 486/66 Mhz in 1996... Got around 2-5 FPS in 320x200. So it was completely infeasible back then.

kaoD• 13 years ago

I've done both and ray tracing techniques are much more complicated and heterogeneous.

exDM69• 13 years ago

This isn't a typical raytracer. Instead, it's a very clever ray marching in a uniform grid. It resembles a Wolfenstein/Doom -style raycaster more than what you usually think of as a raytracer.

yalue• 13 years ago

When I tried to build the project I got a linker error, but running the prebuilt iso (linked in the readme) with qemu worked just fine. A very impressive project!

Edit: The link error is probably just a stupid mistake on my part; I was trying to build on a 64-bit machine. It doesn't seem to have any problems on 32 bit.

Smerity• 13 years ago

For others who might be interested, compilation works fine in Ubuntu 12.04 after `apt-get install build-essential nasm qemu`. If you install libsdl and libsdl-dev you can run the reference version written in C which runs significantly faster.

It's indeed an impressive project, doubly so as it was initally only for a university project. Instead of just making a game in assembly he made the project his own by extending it -- bootable, raytaced, raytraced shadow, textures and so on! =]

300bps2• 13 years ago

Instead of just making a game in assembly

Not to discount what he did, but he didn't write the game in Assembly. He wrote it in C then decompiled it to Assembly and used that as a starting point for the Assembly code.

From the article:

Starting in assembly right away would be a bit too insane, so I first wrote a reference implementation in C

As someone who started in Assembly right away creating several games with a much simpler 6510 CPU, I can vouch for the fact that starting in Assembly would be a bit too insane especially on modern CPUs.

shortsightedsid• 13 years ago

Also, its interesting to think about how badly we can estimate size of code. When I saw the headline, I thought its going to be pretty large with 50K lines of code. Turned out to be much smaller - ~3K lines of code.

That's impressive too!

gizmo686• 13 years ago

What was your linker error? If you haven't already, you should either file a bug or solve it yourself and send a pull request of your solution. As someone who hacks around with small open source projects enough, nothing is more annoying than that type of small error that everyone who knows how to fix it finds the solution to obvious to report (it is probably installing an undocumented dependency), and every who doesn't gives up on the project. Admittedly, I have been guilty of solving these problems for myself many times.

hdra2• 13 years ago

Wow. Impressive project, especially as a university assignment (I am assuming a bachelor's degree), considering I see a lot of people graduating university without being able to even write the most basic CRUD app.

I myself can't even manage to finish a simple 2d game I started months ago.

Kudos to the author.

mjfl• 13 years ago

as a Computer Science student, I am embarrassed that this is true at least for me, though I am eager to learn...

irishcoffee• 13 years ago

Its only embarrassing if you've tried and couldn't figure it out.

hdra2• 13 years ago

the eagerness is the most important thing in learning.

I'm sure we all know SE major students who aim to get a job as a "project manager" right off the bat, not because they actually love/know anything about managing a project, but simply because it is a managerial position where you don't have to code.

ctdonath• 13 years ago

Nicely complements the nearby thread "Building a Modern Computer from First Principles" https://news.ycombinator.com/item?id=5888705

dom96• 13 years ago

As a student who is hoping to study Computer Science in a years time, I hope that the university I enrol at encourages such projects!

pestaa• 13 years ago

Mine has absolutely zero appreciation for anything that is not closely related to academia -- I wish you much, much better luck.

kriro• 13 years ago

Impressive. I also like his approach of prototyping it in C first (I chuckled at the thought of C as a prototyping language). That reference is also in the repo and I hope to at least read that :)

mrmekon4• 13 years ago

Everybody I know who writes assembly language in practice now, self included, prototypes most of it in C first -- why not take the huge headstart from the compiler generated ASM?

And I usually prototype the C in Python first :D

mrbrowning2• 13 years ago

In those cases, are you writing in asm for fun? If not, what advantages do you see in taking this approach over just writing most of the project in C and using inline asm where necessary?

pjmlp• 13 years ago

Why?

Back when I started programming (1986), Basic, C, Pascal and Forth were seen as prototyping languages, before coding the real applications in Z80, 6502 Assembly.

vidarh2• 13 years ago

My major introduction to C was hand optimizing a large C library compiled to M68000 assembly, while complaining incessantly about how shitty the compiler was, as I could at the time easily strip the code down to <40% of original size almost only be removing unnecessary usage of temporary registers... But these days C compilers generate tolerable code in most cases..

mrmekon4• 13 years ago

I'm always amazed by the strange assembly generated by modern compilers. LLVM will auto-vectorize a routine into this awesome NEON SIMD masterpiece... and then throw in a bunch of completely redundant stack loads/stores and refuse to use any registers except r0 and r1! 0_o

You can tell where the devs with Ph.Ds in compiler design are putting all of their effort :)

voltagex_• 13 years ago

Cool! I think this would also be PXE-bootable with iPXE and a chain command.

FreeFull• 13 years ago

Seems to break when you press multiple keys at once. Movement starts and then doesn't stop. Otherwise, it is pretty good.

arsen1k1• 13 years ago

Looks like the kind of app the Kolibri OS (http://kolibrios.org/) would love to see ported to their platform. Is it possible to do?

mosqutip• 13 years ago

I thought my asteroids game in assembly was cool. Great job!

rpicard• 13 years ago

Is the source code online somewhere?

TheAceOfHearts• 13 years ago

Shameless plug of an ASM project I did: https://github.com/cesarandreu/INEL4206-XString (Video in link)

rcthompson• 13 years ago

Now we just need a Redstone x86 processor to run it on.

parski• 13 years ago

It looks more like an Infiniminer clone. Impressive none the less.

mikkom• 13 years ago

Any screenshots?

Bootable Minecraft clone written partly in x86 Assembly

Related Stories