main.lua, turtle.lua

main.lua

@@ -0,0 +1,40 @@
+mkTurtle = require "turtle"
+local screen = {
+   width = love.graphics.getWidth(),
+   height = love.graphics.getHeight(),
+}
+local o = mkTurtle(screen.width/2, screen.height*3/4)
+
+local t = 0;
+function love.update(dt)
+   t = t+ dt
+   
+end
+
+
+
+function love.draw()
+   tt = o:dup()
+
+   --   local fd, lt, rt, bk, pd = tt.fd, tt.lt, tt.rt, tt.bk, tt.pd
+   -- tt.rt(45).fd(10)
+
+   local amultl = 0.8 + math.cos(t*5)/2
+   local amultr = 0.8 + math.cos(t*7)/2
+   local lmultl = 0.7 + math.cos(t*3)/2
+   local lmultr = 0.7 + math.cos(t*4.5)/2
+   local iangle = math.cos(t*2.5)*40-20
+   function trunk(tt, level, length, angle)
+      tt.fd(length)
+      if level > 0 then
+	 tt.lt(iangle)
+	 trunk(tt:dup().lt(angle), level-1, length*lmultl, angle*amultl)
+	 trunk(tt:dup().rt(angle), level-1, length*lmultr, angle*amultr)
+      end
+   end
+
+   trunk(tt, 10, 60, math.sin(t)*180)
+	 
+
+end
+

turtle.lua

@@ -0,0 +1,80 @@
+
+
+local function fd(x, y, ang, steps, penDown)
+   local x2, y2 = x+math.sin(ang)*steps, y-math.cos(ang)*steps
+   if penDown then
+      love.graphics.line(x, y, x2, y2)
+   end
+   return x2, y2
+end
+
+local deg2rad = math.pi/180
+function mkTurtle(x,y,degrees,orig)
+   local penDown = true
+   if x == nil then x = 0 end
+   if y == nil then y = 0 end
+   if degrees == nil then degrees = 0 end
+
+   local self
+   self = {
+      fd = function(steps)
+	 x, y = fd(x, y, degrees*deg2rad, steps, penDown)
+	 return self
+      end,
+
+      bk = function(steps)
+	 x, y = fd(x, y, degrees*deg2rad, -steps, penDown)
+	 return self
+      end,
+
+      rt = function(deg)
+	 degrees = degrees + deg
+	 return self
+      end,
+
+      lt = function(deg)
+	 degrees = degrees - deg
+	 return self
+      end,
+
+      pd = function(isDown)
+	 penDown = isDown
+	 return self
+      end,
+
+      col = function(color)
+	 -- FIXME
+	 return self
+      end,
+
+      dup = function(orig)
+	 return mkTurtle(x, y, degrees, orig)
+      end,
+
+      parent = function()
+	 return orig
+      end,
+
+      inline = function(env, func)
+	 local stub = {}
+	 local meta = {
+	    __index = function(table, key)
+	       if env[key] ~= nil then
+		  return env[key]
+	       end
+	       if _ENV ~= nil and _ENV[key] ~= nil then
+		  return _ENV[key]
+	       end
+	       return nil
+	    end,
+	 }
+	 setmetatable(stub, meta)
+	 setfenv(func, stub)
+	 return func()
+      end,
+   }
+   return self
+end
+
+return mkTurtle
+