striped.lua

--- striped animated interactive wallpaper
--- @thacuber2a03

local bg, fg -- set in _update
local spacing = 9 -- should hardcode?
local width, height = 480, 270

local position = 0
local velocity = 3
local maxVelocity = 0.2
local acceleration = -0.02

local _, lastMouseY = mouse()

function _update()
	bg, fg = theme "desktop0", theme "desktop1"

	position += velocity
	if abs(velocity) > maxVelocity then
		velocity += acceleration * sgn(velocity)
	else
		velocity = maxVelocity * sgn(velocity)
	end

	local _, mouseY = mouse()
	local delta = mouseY - lastMouseY
	if abs(delta) > 5 then velocity += delta / 100 end
	lastMouseY = mouseY
end

function _draw()
	cls(bg)

	local i = 1
	for x=0, width+spacing, spacing do
		local invert = i % 4 < 2
		rectfill(x-spacing/2+1, 0, x+spacing/2+1, height, invert and fg or bg)

		for y=0, height+spacing, spacing do
			local drawY = y+x*(spacing/2)+position

			if not invert then drawY = height - drawY end
			local percent = y/height
			circfill(x, drawY%height, 1+sin(percent), invert and bg or fg)
		end
		i += 1
	end
end