Now that I’ve got register machines working, one of the next ideas I had was to implement different wrapping modes. Currently, as it stands, X and Y are passed into the machine as floating point numbers from [0, 1] across the image and output is expected to be [0, 1] for each of R, G, and B. Any values that end up outside of that range, we truncate down to that range. But some of our mathematical functions (multiplication, exponentiation, negation, etc) tend to generate numbers way out of this range. But they don’t have to!

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Okay. First Pictogeneis machine: a register based machine. Today we’re going to create a very small language with a small number of registers that can read from the outside world, write colors, and act as temporary variables.

Something like this:

gt? t0 b y x r
add g y x
abs b x
inv t0 g
add r g x
sub t0 b r
mul x r b
abs y x

In each case, the first argument is the output and the rest are inputs. So:

# gt? t0 b y x r
if (b > y) {
    t0 = x;
} else {
    t0 = r;
}
 
# add g y x
g = y + x

# abs b x
b = |x|
...

Where x and y are the input point x and y mapped to the range [0, 1]; r, g, b are the output colors in the same range and t{n} are temporary registers just used during the program.

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PICTOGENESIS REBORN!

I don’t know if I ever actually posted it publically, but one of the ideas I’ve had percolating for the longest time is combining tiny interpreters and genetic algorithms to make generative art.

The basic idea is to generate programs (in various styles) that can take x,y coordinates and return colors. Then apply that to every pixel on an image to make generative art. Once we have, figure out a way to mutate/breed the programs so that we can apply a genetic algorithm to them and make awesome images! Sort of like Electric Sheep (that brings back memories).

The evolution point of view was actually a pretty tricky problem, since programs can have a number of different representations. I could compile them to bytecode and mutate that, but how do I make most code at least potentially meaningful?

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Let’s take yesterday’s Worm Coral and turn it up to 11!

Now we have:

• Whenever a worm gets stuck, it will ‘backtrack’: it will instead expand from the previous position recursively

That means that the initial 10 worms should always be able to fill the entire world! Even if one closes off an area, that one can eventually fill it up:

I like how occasionally you get one spindly bit (usually early in the run) that another goes through. It reminds me of Blokus It does take a while.

In addition, I wanted to play a bit with simulationism:

• Worms can potentially changeColor each frame
• Every framesPerGeneration check if each worm dies deathChance or spawns a child worm (spawnChance)
• If a worm dies, it is removed from the simulation
• If a worm spawns, it creates a new child at it’s current location
  • If spawnIncludesHistory is set, the child can backtrack into the parent’s history
  • If spawnVariesColor is set, the child will (potentially, it’s random) have a slightly different color

Let’s check it out!

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Today, I’m going to work on using worms to generate coral, similar to what I did way back when I was generating omnichromatic images.

In a nutshell:

• Spawn n worms
• On each tick:
  • Each worm tries to randomly move one direction
  • If it cannot, increment that worm’s stuck counter
  • If it can, restart the stuck counter
  • If a worm is stuck long enough, kill it off and spawn a new worm

Eventually, we’ll fill the entire space with colors that end up looking a bit like coral. I’ll probably extend this later, since there are a lot of cool tweaks you can do with this general idea.

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Okay, sketch 2: Boids!

The basic idea is to create a bunch of particles (the Boids in this case) and apply to them each a series of simple, limited rules that rely neither on communcation between the Boids nor a global controller and see what behaviors you can generate. Specifically, can you replicate the flocking behavior found in birds, since birds can obviously fly together without hitting one another and also without some lead bird giving orders.

Something like this:

For this case, there are three rules:

• seperation - Fly away from any Boids that are too close to you (to avoid collision)
• alignment - Align yourself to fly in the same direction as any Boids in your field of vision
• cohesion - Fly towards the center point of the Boids you can see

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One thing that I’ve been hoping to get into a bit more is the idea of Generative Art. Essentially, use any of a wide variety of algorithms to generate art. To do that, and so that the art can be generated right in front of you in the browser, I’m going to use the p5js library. It gives you a nice API of graphical primitives and takes a simple setup and draw function and does the rest.

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Another quick post.

What feels like a lifetime ago, I wrote a post about finding ec2 instances by name. I honestly use that script just about every day, mostly for automatically finding instances to SSH to (a la SSH config tricks). But there are a few other quick things I’ve done with it:

• ec2-script - Run a script on all instances of a given name
• ec2-disk - A specialization of ec2-script to check main disk usage
• terminate - A script that I use with ec2 to terminate instances from the command line
• ec2-cycle - Slow cycle a given set of ec2 instances by terminating so many per minute

All of which are included in my dotfiles.

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A quick post today.

I find myself working with a surprising number of different languages/environments day to day. In the last week, I’ve worked with PHP, Python, Go, Ruby, and Javascript. And different versions of several of those. While I could install something like virtualenv for Python / rbenv for Ruby / etc, I already have a tool exactly designed for this sort of thing: Docker!

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The Sender Policy Framework is one of those things that’s really powerful and useful to help prevent phishing and email spam, but can be a royal pain to work with. Specifically, SPF is a series of DNS TXT records¹ with a specific format that can be looked up by any email service to verify that an email was sent by a server that should be authorized to send email on your behalf. For example

"v=spf1 ip4:192.0.2.0/24 ip4:198.51.100.123 a -all"

• v=spf1 - tells the client this is an SPF record and should always start the record
• {key}[:{value}]? - one of many different key/value pairs that can define the record
  • in the case above a ip4 key species an IPv4 address range that can send emails on your behalf (the value can be optional)
  • the a above is another special case where if the sender domain ([email protected] would be example.com) resolves via a DNS A record to the server that sent the email, it’s allows
• -all is a fallthrough case meaning ‘fail all that didn’t match a previous case

There are a number of other cases, but we’ll get to the other interesting ones in a bit.

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