Sunflowers!

I have always loved sunflowers. So when I announced this to one of my friends he replied,

“I’m scared of sunflowers, they are tall and disgusting and it looks like they will fall down and attack you from above”.

I thought he was joking. So I went home and made him a little program of procedurally generated sunflowers using PICO-8.

Unfortunately not even digital sunflowers could convince him that these flowers are amazing. I quite like them, so now I’m using them as my profile picture on Github. If you want to run this little program you can find it on BBS. It’s written using closures and you can find the code below. To give a simple overview of what is going on, the sunfl function returns a function f which when called has two effects:

It updates the state within f (this is what makes the sunflower grow)
It renders the sunflower.

It would probably be easier to just use tables instead but I wanted to experiment a bit with closures. Here is the code.

lua

function sunfl()
	-- petal vars
	local n=0
	local const=rnd()+0.5
	local ang=360/137.5
	local maxrad = rnd()*3+3
	local r=0
	local a=0
	local pet =0.5+rnd()/2
	local npets = flr(rnd()*10)+15
	local madecenter=false
	
	-- root vars
	local root = {4,3,3,11,3,3}
	local miny = rnd()*80+10 
	local cx,cy = 
	(rnd()-0.5)*128+64,128-8

	local rooti= 0
	local growspd = 0.001
	
	local function makeroot()
		for i=1,50 do
			if rnd() > 0.999 then
				rooti+=1
			end
			local r = -flr(rnd(3))+3+rooti
			if r < 0 then
				r = 1
			end 
			if r > #root then
				r = #root
			end
			
			cy-=growspd
			cx =cx+(rnd()-0.5)
			pset(cx,cy,root[r])
			growspd += 0.0001
			if growspd > 0.1 then
				gridspd = 0.1
			end
			
			if cy < 120 and rnd()<0.01 then
				d = sgn(rnd()-0.5)
				local x,y = cx,cy
				for j=1,rnd(5)+5 do
					 x+=rnd()*d
					 y+=(rnd()-0.8)
					 pset(x,y,11)
				end
			end
		end
	end
	
	local function inner()
		if not madecenter then
			circfill(cx,cy,maxrad+1,0)
			madecenter=true
		end
		a=(n*ang)%1
		r=const*sqrt(n)
		local x,y=
		cos(a)*r+cx,
		sin(a)*r+cy
		pset(x,y,4)
		n+=1
	end
	
	local function outer() 
		local ps=pet*rnd()
		local osc=(sin(a*npets)+2)*ps
		if(osc<1)osc=1
		local x,y=
		cos(a)*maxrad*osc,
		sin(a)*maxrad*osc
		local c = 9
		if rnd()>0.6 then
			c=10
		end
		pset(x+cx,y+cy,c)
		a+= 0.01
	end 
	
	return function()
		local fn = nil
		if cy > miny then
			makeroot()
		else
			for i=1,50 do
        if(r<maxrad)then
          inner()
        else
          outer()
        end
			end
		end
	end
end


function reset() 
	fls = {}
	for i=1,10 do
		fls[#fls+1]=sunfl()
	end
end

started=false
map(0,0,0,0,16,16)
function _draw()
	if btn(5) then 
		if(not started)started=true
		reset()
	end
	if btn(4) then
		map(0,0,0,0,16,16)
		fls={}
	end
	if(not started)return
	for f in all(fls) do
		-- vary the speed of flowers
		if rnd()>0.2 then
			f()
		end
	end 
end

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