UVM Wishlist

[maximecb]

This is a list of potentially fun things to work on that would be useful for UVM and its software ecosystem. An easy way that you can contribute to UVM is to write example programs, or useful utility code to be shared with the community, and report any bugs or difficulties you run into along the way.

Some ideas:

• C code for line drawing
• Text/font rendering code
• Basic printf implementation in ncc/include/stdio.h
• A simple text editor running inside UVM
• Rotating 3D wireframe cube example.
• Demoscene-style fire effect
• Demoscene-style plasma effect
• 2.5D raycasting example
• Mini LISP interpreter/REPL (read-eval-print loop)
• More demoscene-style effects
  • Tunnel effect, rotozoom, etc?
• Function to fill anti-aliased circles (/ncc/include/uvm/graphics.h)
• Fun examples making use of the audio output API
• Simple 2D platformer game
• Port implementation of BLAKE3 or better crypto-safe hashing function
  • This will be used in a networking context
• C code for flat-shaded polygon (triangle) rendering
• Create a UVM logo, drawn using UVM
• Recreation of the amiga boing ball demo/example ❤️
• Get the Doom shareware code running on UVM?
  • Any way to directly transpile machine code for this?

My intent is to share all examples code under the CC0 1.0 license (a public domain dedication) so that people can get inspired from it and do with it as they please.

And generally speaking, if you write any kind of simple game for UVM, the code is readable, and you're willing to add it to this repo as part of the examples, that could be a useful contribution to the ecosystem :)

Smaller pull requests are easier to review and more likely to get merged quickly.

[calroc]

I'm a little embarrassed to show this is the state it's in, but I've been doodling since hearing about the project Saturday and I've got a start on some of the things on the list. I've got simple and crude text rendering with anti-aliasing / alpha blending and I am in the middle of implementing a Wu line drawing routine (but I have to go to sleep now, I'll finish it in the morning when my brain's working better.) Anyway, it's here: https://github.com/calroc/Thun/tree/master/implementations/uvm-ncc Like I said, it's embarrassing, but I wanted to be encouraging and I'm really excited about UVM! I'm going to use it to create a kind of IDE for a concatinative language called Joy. It's not BASIC but it will have a REPL and a simple text editor, so... there's that. :) Ciao!

[maximecb]

Hi @calroc! Very excited to see you doodling with UVM! :)

I would definitely be interested in including some of your graphics code in the UVM examples if you're willing.

The only thing that's a question mark in my mind is the compatibility of the inconsolata font with a CC0 license. Ideally I'd like the examples code and all its assets to be CC0 so that people can just do anything they want with it without worrying about licenses. I did some googling and it seems hard to find CC0 TTF monospaced fonts though.

[hd-COO7]

@maximecb I would love to pick couple of things like work on ncc/include/string.h and ncc/include/stdio.h. New to VMs so trying it for first time.

[calroc]

I've almost got the Wu anti-alias line algorithm licked. I'm doing something wrong though because I keep getting artifacts in the middle of the line (drawing from both ends at the same time.)

In re: CC0 licensed fonts, I looked too and couldn't find any monospaced fonts that weren't pixel fonts, but some of those are pretty nice:

• https://ggbot.itch.io/public-pixel-font
• https://fontlibrary.org/en/font/pixel-operator
• https://datagoblin.itch.io/monogram

And I like "Tom Thumb" 4x6 pixel font: https://robey.lag.net/2010/01/23/tiny-monospace-font.html and https://github.com/gheja/tom-thumb-ttf

[maximecb]

@maximecb I would love to pick couple of things like work on ncc/include/string.h and ncc/include/stdio.h. New to VMs so trying it for first time.

That would be great. I think for string.h the C compiler is mature enough to implement everything. There are some tests in ncc/tests/string.c

For stdio, I think we should be able to implement a minimalistic printf fairly easily. For the other file iO functions it's more tricky because we need to design system calls for files/streams and that hasn't been done yet. There's another open issue for that.

[maximecb]

I've almost got the Wu anti-alias line algorithm licked. I'm doing something wrong though because I keep getting artifacts in the middle of the line (drawing from both ends at the same time.)

Excited for line drawing. Once we have better float support we can use that to draw wireframe graphics.

In re: CC0 licensed fonts, I looked too and couldn't find any monospaced fonts that weren't pixel fonts, but some of those are pretty nice:

• https://ggbot.itch.io/public-pixel-font
• https://fontlibrary.org/en/font/pixel-operator
• https://datagoblin.itch.io/monogram

And I like "Tom Thumb" 4x6 pixel font: https://robey.lag.net/2010/01/23/tiny-monospace-font.html and https://github.com/gheja/tom-thumb-ttf

Bitmap fonts can totally work. There are several more options on https://opengameart.org/ IIRC. You can directly search for game assets with a CC0 license which is pretty useful.

[maximecb]

Just looked at that monogram font and it looks quite gorgeous :)

[calroc]

I've kind of got Wu lines working (at least for the "first octant"! That's the easy octant you know.) I gave up on the symmetrical version (where you draw the line from both ends simultaneously so you only have to do half as many iterations) because I couldn't get rid of artifacts at the center of the lines. I have some ideas how to fix that, but in the meantime just sweeping the whole major axis works fine (and we're not dealing with a 1980's microprocessor after all, eh?) I don't special-case the end points either, so it's not really the proper Wu algorithm. Still it looks nice!

I tried a pixel font in the crude font machinery that I have so far, but (of course) Imagemagick draws the TTF scaled and with anti-aliasing, so it's not the actual bitmap, more like a screenshot of the bitmap, eh? (But if you want slightly blurry "pixel" fonts, that's good to go.)

I'll write some code for actual bitmapped fonts... Interestingly the monogram bitmap is distributed as a JSON literal in it's own monogram-bitmap.json file. It's also a Python literal. I'm too old to tell if this is cool or not? In any event, I can work with it. :)

{
"0":[0,0,0,14,17,25,21,19,17,14,0,0],
"1":[0,0,0,4,6,4,4,4,4,31,0,0],
"2":[0,0,0,14,17,16,8,4,2,31,0,0],
"3":[0,0,0,14,17,16,12,16,17,14,0,0],
...

[calroc]

Excited for line drawing. Once we have better float support we can use that to draw wireframe graphics.

In re: float support, I'm a weirdo and an iconoclast, but my gut feeling is that you don't need floating point in a 64-bit world. However, as a matter of practicality (not to mention people taking your project seriously) there is all that sweet hardware that's already there and speaks float, eh? I'm not a graphics programmer, I look with awe on the folks who write shaders and deal with programming the GPU. What I'm getting at is, don't take my opinions on the matter seriously.

On the one hand, it would be so cool if UVM could provide simple API for accelerated graphics, on the other hand that's a huge, deep rabbit hole that is made out of other rabbit holes in an ever-expanding fractal.

That said, Chuck Moore used to have a wireframe 3D CAD system that fit on a deck of punch cards that he kept in his shirt pocket. I'm going to look into doing 3D math with integers (my dialect of Joy doesn't have floats), there's something called "rational trigonometry" which sounds promising. I wrote a 3D math system ages ago based on the code in "Physics For Game Developers", I got as far as a rotating cube. Hopefully I can come up with something. :)

[maximecb]

I've kind of got Wu lines working (at least for the "first octant"! That's the easy octant you know.) I gave up on the symmetrical version (where you draw the line from both ends simultaneously so you only have to do half as many iterations) because I couldn't get rid of artifacts at the center of the lines. I have some ideas how to fix that, but in the meantime just sweeping the whole major axis works fine (and we're not dealing with a 1980's microprocessor after all, eh?) I don't special-case the end points either, so it's not really the proper Wu algorithm. Still it looks nice!

That's too bad. I hope you'll be able to make it work. At the moment we just have an interpreter and no JIT. The platform needs time to mature before effort is spent on building a JIT imo, so we do need to be able to squeeze as much performance as possible, especially for graphics.

I'll write some code for actual bitmapped fonts... Interestingly the monogram bitmap is distributed as a JSON literal in it's own monogram-bitmap.json file. It's also a Python literal. I'm too old to tell if this is cool or not? In any event, I can work with it. :)

It's probably because all the web kids can't be bothered to read a binary file 😅

In re: float support, I'm a weirdo and an iconoclast, but my gut feeling is that you don't need floating point in a 64-bit world. However, as a matter of practicality (not to mention people taking your project seriously) there is all that sweet hardware that's already there and speaks float, eh?

I feel that way too. You can get really far with fixed point integer arithmetic, and with 32 or 64-bit integers, it seems like you basically shouldn't need floats at all for 2D or 3D video games. It's almost too bad that more engineering effort wasn't spent on accelerating fixed point computation... But like you said, there's just a lot of floating point hardware out there. It would feel wasteful not to have that capability. I also feel like people are going to expect FP support and would find it weird, would find UVM hard to target if it wasn't available 🤷‍♀️

On the one hand, it would be so cool if UVM could provide simple API for accelerated graphics, on the other hand that's a huge, deep rabbit hole that is made out of other rabbit holes in an ever-expanding fractal.

The current interpreter should be fast enough that we'll be able to program something a Doom-like raycasted game. With a JIT compiler, we should be able to do decent 3D graphics with software rendering. Beyond that, I have more idea for maybe a SIMT execution model which could make use of multiple CPU cores, but that's much farther in the future. I also have some ideas for adding some simple "blitting" or alpha blending primitives that use SIMD on the host system. Kind of inspired by the Amiga. :)

That said, Chuck Moore used to have a wireframe 3D CAD system that fit on a deck of punch cards that he kept in his shirt pocket. I'm going to look into doing 3D math with integers (my dialect of Joy doesn't have floats), there's something called "rational trigonometry" which sounds promising. I wrote a 3D math system ages ago based on the code in "Physics For Game Developers", I got as far as a rotating cube. Hopefully I can come up with something. :)

Speaking of wireframe... Once we have line drawing working and I have structs working in NCC, I'd like to program an animation that's like a 3D fly through a wireframe city. Kind of like this, but in purple-ish synthwave colors :)

https://www.youtube.com/watch?v=z6aMAPndP8Q

[neauoire]

Have you considered implementing bresenham until you can have anti-aliased lines? I couldn't find it in the examples folder

typedef struct {
	double x, y;
} Point2d;

static void
line(Uint32 *dst, Point2d p0, Point2d p1, Uint32 color)
{
	int p0x = (int)p0.x, p0y = (int)p0.y;
	int p1x = (int)p1.x, p1y = (int)p1.y;
	int dx = abs(p1x - p0x), sx = p0x < p1x ? 1 : -1;
	int dy = -abs(p1y - p0y), sy = p0y < p1y ? 1 : -1;
	int err = dx + dy, e2;
	for(;;) {
		putpixel(dst, p0x, p0y, color);
		if(p0x == p1x && p0y == p1y)
			break;
		e2 = 2 * err;
		if(e2 >= dy) {
			err += dy;
			p0x += sx;
		}
		if(e2 <= dx) {
			err += dx;
			p0y += sy;
		}
	}
}