feat: Initial commit

README.md

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+# Lissajous table
+
+![Preview](example.gif)
+
+I was inspired by this video "[Making a physical Lissajous curve](https://www.youtube.com/watch?v=4CbPksEl51Q)"
+and thought "That looks pretty cool and easy to code". So here it is a program
+which draws a resizable lissajous table. The wider or higher your window is
+the more circles will be drawn.
+
+## Starting
+
+To run this project you need to install [Love2D](https://love2d.org) yourself.
+There is a great tutorial on how to do all of this [here](https://love2d.org/wiki/Getting_Started).
+

conf.lua

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+function love.conf(t)
+  t.window.title = "Lissajous tables"
+  t.window.resizable = true
+end

main.lua

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+-- NEEDS OPTIMIZATIONS
+local angle = 0
+local relativeGap = 0.5
+local relativeMarker = 0.1
+local relativeWidth = 0.08
+local rows, cols, circles, curves, markerSize, gap
+local opacity = 0.3
+local constants = {
+  circleRadius = 20,
+  speed = 1,
+  drawLines = false,
+  colors = true,
+  drawMarkers = true,
+  drawCircles = true,
+  drawTable = true
+}
+
+function HSV(h, s, v, a)
+  if s <= 0 then return v,v,v end
+  h, s, v = h/256*6, s/255, v/255
+  local c = v*s
+  local x = (1-math.abs((h%2)-1))*c
+  local m,r,g,b = (v-c), 0,0,0
+  if h < 1     then r,g,b = c,x,0
+  elseif h < 2 then r,g,b = x,c,0
+  elseif h < 3 then r,g,b = 0,c,x
+  elseif h < 4 then r,g,b = 0,x,c
+  elseif h < 5 then r,g,b = x,0,c
+  else              r,g,b = c,0,x
+  end return (r+m),(g+m),(b+m), a or 1
+end
+
+function addColors(h1, h2)
+  local r1, g1, b1, a1 = HSV(h2, 255, 255)
+  local r2, g2, b2, a2 = HSV(h1, 255, 255)
+  return (r1+r2)/2, (g1+g2)/2, (b1+b2)/2, (a1+a2)/2
+end
+
+local function distance(x1,y1,x2,y2)
+  return ((x1-x2)^2 + (y1-y2)^2)^0.5
+end
+
+function Curve()
+  local self = {}
+  self._points = {}
+  self.draw = function(self)
+    if #self._points >= 4 then
+      love.graphics.line(self._points)
+    end
+  end
+  self.addPoint = function(self, x, y)
+    table.insert(self._points, x)
+    table.insert(self._points, y)
+  end
+  self.clear = function(self)
+    self._points = {}
+  end
+  return self
+end
+
+function genTable(default, N)
+  local t = {}
+  for i=0, N-1 do
+    if type(default) == "function" then
+      t[i] = default()
+    else
+      t[i] = default
+    end
+  end
+  return t
+end
+
+function roundDown(X)
+  return X - (X / 10)
+end
+
+function recalc(w, h)
+  local realSize = (relativeGap + 1) * constants.circleRadius
+  local rows = roundDown(w  / realSize)
+  local cols = roundDown(h / realSize)
+  circles = genTable(angle, math.max(rows, cols))
+  curves = {}
+  for i=0, rows-1 do
+    curves[i] = genTable(Curve, cols)
+  end
+end
+
+function love.load(args, unfilteredArgs)
+  for i=1,#args do
+    for name in pairs(constants) do
+      if "-"..name == args[i] then
+        if type(constants[name]) == "boolean" then
+          constants[name] = args[i+1] == "true"
+        elseif type(constants[name]) == "number" then
+          constants[name] = tonumber(args[i+1])
+        end
+        i = i + 1
+        break
+      end
+    end
+  end
+
+  markerSize = constants.circleRadius*relativeMarker
+  gap = constants.circleRadius*(1+relativeGap)
+
+  recalc(love.graphics.getDimensions())
+end
+
+function love.update(dt)
+  angle = angle + constants.speed * dt
+  for i in pairs(circles) do
+    circles[i] = angle * (i+1)
+  end
+  if angle > math.pi*2 then
+    angle = angle % math.pi*2
+    for _, j in pairs(curves) do
+      for _, curve in pairs(j) do
+        curve:clear()
+      end
+    end
+  end
+end
+
+function setColor(r,g,b,a)
+  if constants.colors then
+    love.graphics.setColor(r,g,b,a)
+  else
+    love.graphics.setColor(1, 1, 1, a)
+  end
+end
+
+function drawMarker(x, y)
+  if constants.drawMarkers then
+    love.graphics.circle("fill", x, y, markerSize)
+  end
+end
+
+function drawCircle(x, y)
+  if constants.drawCircles then
+    love.graphics.circle("line", x, y, constants.circleRadius)
+  end
+end
+
+function love.draw()
+  local w,h = love.graphics.getDimensions()
+
+  love.graphics.setLineJoin("none")
+  love.graphics.setLineStyle("smooth")
+  -- Circles and lines
+  for i, circleAngle in pairs(circles) do
+    local dist = constants.circleRadius + (i+1) * gap*2
+    local p = i/#circles
+
+    -- X-axis
+    if dist+gap < w then
+      local x = dist + constants.circleRadius * math.cos(circleAngle-math.pi/2)
+      local y = gap  + constants.circleRadius * math.sin(circleAngle-math.pi/2)
+      setColor(HSV(p*511, 255, 255))
+      love.graphics.setLineWidth(constants.circleRadius * relativeWidth)
+      drawMarker(x, y)
+      drawCircle(dist, gap)
+
+      if constants.drawLines then
+        setColor(HSV(p*511, 255, 255, opacity))
+        love.graphics.line(x, 0, x, h)
+      end
+    end
+    -- Y-axis
+    if dist+gap < h then
+      local x = gap  + constants.circleRadius * math.cos(circleAngle-math.pi/2)
+      local y = dist + constants.circleRadius * math.sin(circleAngle-math.pi/2)
+      setColor(HSV(p*511, 255, 255))
+      love.graphics.setLineWidth(constants.circleRadius * relativeWidth)
+      drawMarker(x, y)
+      drawCircle(gap, dist)
+
+      if constants.drawLines then
+        setColor(HSV(p*511, 255, 255, opacity))
+        love.graphics.line(0, y, w, y)
+      end
+    end
+  end
+
+  -- Draw intersection point
+  for i, circleAngle1 in pairs(circles) do
+    for j, circleAngle2 in pairs(circles) do
+      local distX = (constants.circleRadius + (i+1) * gap*2)
+      local distY = (constants.circleRadius + (j+1) * gap*2)
+      if distX+gap < w and distY+gap < h then
+        local x = constants.circleRadius * math.cos(circleAngle1-math.pi/2) + distX
+        local y = constants.circleRadius * math.sin(circleAngle2-math.pi/2) + distY
+        
+        setColor(addColors(i/#circles*511, j/#circles*511))
+        drawMarker(x, y)
+        curves[i][j]:addPoint(x, y)
+      end
+    end
+  end
+
+  -- Draw curves
+  if constants.drawTable then
+    for n1, j in pairs(curves) do
+      for n2, curve in pairs(j) do
+        setColor(addColors(n1/#circles*511, n2/#circles*511))
+        curve:draw()
+      end
+    end
+  end
+end
+
+function love.resize(w, h)
+  angle = 0
+  recalc(w,h)
+end