Posts tagged with simulation

ants devlog 2

this is part of a series. see the previous post here

ants

now that we have a world, let’s create life in it. because we are working with systems it seems imperative we create a model of our life cycle. thus:

→ birth
    ↪ struggle
        ↪ death

in other words, to create life true to life, we must allow our ants to live, to struggle, and to die. once we have these, we’ll have our most basic simulation

notice!

because struggle is often difficult to represent visually, we will be showing movement in its place

birth

but how will we birth our ants? ‘ants’ is of course a generalized term here, little more than metaphor, but if we follow our metaphor as example we open ourselves to a whole complex reproduction apparatus, queens and soldiers and social roles and all, which is more than we are ready to simulate now. we’ll need another way to birth them, with an artificially increased control

a shame: we must reveal ourselves so early

revealing the creators hand

pico-8 offers optional mouse cursor support. it’s a sort of imitation secret, in that only its implementation seems obscure, its existence is known by most who use the program. also, more relevantly, it seems the perfect way to spawn out ants: use the mouse to select a pixel, click, and bring a single ant to life

to enable the mouse, we need only call the below function somewhere in our program. don’t worry what it means now. the meanings mostly unimportant ¹

 poke(0x5f2d, 1)

at least now we have a use for our _init() function: to init our cursor. let’s put that at the top of our file:

function _init()
	poke(0x5f2d, 1)
end

try to run it now? does anything happen? no: we need to make our hand

revealing the creator’s hand, pt 2

hi! my name is j konger. its a pseudonym, of course. few parents give their child a single initial name. i had the idea this devlog would be fun to write in the voice of a tutorial, but the more i write on this the more i realize i need to drill down, explain things neither you or i find very interesting. instead of scrapping this work however (in accordance with my site’s first rule), i am changing course into simple narrative. i hope you don’t mind.

a shame: we must change our course so early

cursor

code

this is the image i used for my cursor. you’ll notice it’s the pico 8 cursor almost exactly, with the color changed. we’ll get to that later, maybe several posts from now

and this is the code i used to make the cursor follow the mouse, which i put in a separate tab:

-- cursor

function cur_init()
	cur_spr=1
	cur_x=60
	cur_y=60
end

function cur_draw()
	spr(cur_spr,cur_x,cur_y)
end

function cur_update()
	--mouse loc
	cur_x=stat(32)-1
	cur_y=stat(33)-1
end

and, under our main tab, we now have this:

function _init() 
   -- allow mouse :)
   poke(0x5f2d, 1)
   cur_init()
end

function _draw()
	cls(4)
	cur_draw()
end

function _update60()
   cur_update()
end

explanation

let’s start with that second part of code, as its simplest: for readability, we add a new init, update, and draw function to our cursor, then just call them in the generic version of each. we call this ‘separation of concerns’. we call this ‘elegant code’

the other tab is simple also, just not as much. let’s go function by function, ok? i think that sounds nice:

cur_init

here, we just set some defaults. cur_spr is the index of our sprite, cur_x and cur_y the starting position of our cursor, which we add only because we need to call it in…

cur_draw

here were merely draw the sprite to screen: spr() draws a sprite, and cur_x and cur_y tell it where to go, x- and y-wise. as we’re using the mouse here, we are continuing to use obscurant functions. all we need to know for our purposes is that stat(32) returns our cursor’s x coordinate, stat(33) its y, and that we subtract one pixel distance from each so our cursor points at the coordinate rather than overlaps, thus looking overall more ‘real’ to our precious user (in truer words ‘familiar’)

end

so now we have a hand in our own creation. if nothing else, that’s worthy of our pride. reach out now, with your pointer device of choice, and touch your world. hit ctl-r on your keyboard to run the app and watch the cursor move

full code and downloads

cartridge

(right click to save, open in pico-8)

full code

-- ants
-- by j konger

function _init() 
   -- allow mouse :)
   poke(0x5f2d, 1)
   cur_init()
end

function _draw()
	cls(4)
	cur_draw()
end

function _update60()
   cur_update()
end


-->8
-- cursor

function cur_init()
	cur_spr=1
	cur_x=60
	cur_y=60
end

function cur_draw()
	spr(cur_spr,cur_x,cur_y)
end

function cur_update()
	--mouse loc
	cur_x=stat(32)-1
	cur_y=stat(33)-1
end

i’d like to have embeds here in a later post, once i figure out how to do that with my static site generator. perhaps that will exist by the time the game gets interesting

ok, you wanna know? here’s the explanation i used to learn it ↩

Jan 30, 2025

ants devlog 1

to live is to struggle, of course, as well to die; pico-8 is a fantasy computer console.

in pico-8 i am simulating bugs. it is clear they aren’t actual bugs, but bugs are the smallest creature i’ve seen that was also living (in high school, with microscopes, we made the bacteria die). therefore i am calling my creatures bugs, as a tip of the hat to the fact that they are living (or in other words outside of my control)

world

first we must create a world for them to live in. pico8 offers three default functions, _init(), _draw(), and _update() (or, in our case, the closely related _update60() to do something similar in 60fps) to simulate our world, so let’s start with these

_init() creates our world. at the moment we will be existentialists and encounter it as given. thus we will not touch upon it now

_update60() creates action in our world. now, as perhaps idealists, we will ignore this for now.

_draw() in fact is all we need to create our world. software after all is not concerned with reality, only representation, thank god. thus, we need only add the color of dirt to our draw function, as dirt is the insects’ natural home. pico-8 uses a integer index-based color palatte, so let’s draw with that now:

function _draw()
    cls(4)
end

what does this mean? _draw(), run every frame, will create an image of all we’ve made. within in, cls() paints the screen a single color ¹, which we’ve set to 4, in other words brown, the color of earth

every second, in other words, we will be reminded the earth is brown. i find this wonderful

our world so far: so much dirt

clears the graphics buffer, so to say ↩

simulation

Mar 21, 2025