nunufractree5.lua

-- z to grow a new tree
-- x to grow a branch
-- up arrow to select +1
-- down arrow to select -1
-- right arrow to select newest
-- left arrow to select oldest

function branch(tree,ox,oy,length,depth,angle,spread,parent,child)

	-- new xy from origin
	local nx = ox + length * cos(angle)
	local ny = oy + length * sin(angle)

	--circfill(ox,oy,1,9)
	--line(ox,oy,nx,ny,10)

	-- set parent index
	local parent = parent or 0
	local child = child or {}
	local current = #tree+1

	-- first branch creates a parent from origin
	-- otherwise tells its parent the good news
	if parent == 0 then
		tree[parent] = {x=ox,y=oy,c={current}}
	else
		add(tree[parent].c,current)
	end

	-- write to tree
	tree[current] = {x=nx,y=ny,p=parent,c=child}

	-- recurse branch
	if depth > 0 and length >= 1 then

		-- special sauce per step
		depth -= 1
		length = length

		branch(tree,nx,ny,length,depth,angle+spread,spread,current)
		branch(tree,nx,ny,length,depth,angle-spread,spread,current)
	end

end


function drawtree(tree)

	local nodecolor,linecolor

	for i=1,#tree do
		if i == highlight then
			nodecolor = 12
			linecolor = 12
			else
			nodecolor = 9
			linecolor = 5
		end

		-- origin xy
		local ox = tree[i].x
		local oy = tree[i].y
		-- parent xy
		local px = tree[tree[i].p].x
		local py = tree[tree[i].p].y

		line(px,py,ox,oy,linecolor)
		circfill(ox,oy,1,nodecolor)
	end

end


--- the tree ---------- 

bonsai = {}
highlight = 1

function _init()

	local defaultx = 64
	local defaulty = 120
	local defaultlength = 16
	local defaultdepth = 1
	local defaultangle = 0.25
	local defaultspread = 0.11

	function spawntree()
		bonsai = {}
		highlight = 1
		branch(bonsai,defaultx,defaulty,defaultlength,defaultdepth,defaultangle,defaultspread)
	end

	spawntree()

end


function _update()

	-- z to snip at highlight
	if btnp(4) then
		-- z to generate new tree
		--spawntree()
	end

	-- x to branch at highlight
	if btnp(5) then

		-- step calculations
		local growx = bonsai[highlight].x
		local growy = bonsai[highlight].y
		local growlength = 4+(rnd()+rnd()+rnd()+rnd())
		local growdepth = 1
		local growangle = 0.5-rnd()/2
		local growspread = 0.11

		branch(bonsai,growx,growy,growlength,growdepth,growangle,growspread,highlight)
	end

	-- left and right to snap highlight
	if btnp(0) then
		highlight = 1
	end
	if btnp(1) then
		highlight = #bonsai
	end

	-- up and down to highlight node
	if highlight >= 1 and highlight <= #bonsai then
		if btnp(3) then
			highlight -= 1
		end
		if btnp(2) then
			highlight += 1
		end
	end

	-- fix out of bounds highlight
	if highlight < 1 then
		highlight = 1
	end
	if highlight > #bonsai then
		highlight = #bonsai
	end

end


function _draw()

	cls()
	drawtree(bonsai)
	
	print("size     "..#bonsai,0,0,10)
	print("selected "..highlight,0,7,12)

end