Fix infinite loop bug, add FFI enum test, add moving camera

enumerations.lua

@@ -1,4 +1,27 @@
 local enum = require 'enumeration'
+local ffi = require 'ffi'
+
+local function NadFFI( p )
+  local rmt = { 
+      __lt = function(a, b) return a.n / a.d < b.n / b.d end,
+      __eq = function(a, b) return a.n == b.n and a.d == b.d end,
+      __call = function(t) return t.n / t.d end,
+      __tostring = function(t) return string.format( "<%d/%d>", t.n, t.d ) end
+  }
+  ffi.cdef "typedef struct { uint32_t n, d; } rational;"
+  ffi.metatype( "rational", rmt )
+  local list = ffi.new( "rational[?]", 123456 )
+  local d, i = 1, 1
+  repeat
+    d = d * p
+    for n = d - 1, 1, -p do
+      list[i].n = n
+      list[i].d = d
+      i = i + 1
+    end
+  until i > 123456 / p
+  return list
+end
 
 local function CalkinWilf()
   local n, d = 1, 1
@@ -79,8 +102,19 @@ local function Dyad()
     end )
 end
 
+local function Nad( p )
+  local n, d = -1, p
+  return enum( function()
+      n = n + p
+      if n > d then n, d = 1, d * p end
+      return n / d
+    end )
+end
+
 return { 
   Dyad = Dyad,
+  NadFFI = NadFFI,
+  Nad = Nad,
   SternBrocot = SternBrocot,
   CalkinWilf = CalkinWilf,
   Random = Random,

main.lua

@@ -1,8 +1,8 @@
 local enumerations = require 'enumerations'
 local twintree = require 'twintree'
 local step = coroutine.wrap( twintree.buildIncremental )
-local a = enumerations.Dyad()
-local b = enumerations.Random()
+local a = enumerations.NadFFI( 2 )
+local b = enumerations.SternBrocot()
 step( a, b )
 
 --Use LOVE for plotting.
@@ -11,36 +11,28 @@ local love = assert( love )
 local canvas = love.graphics.newCanvas()
 local numMapped, pointList = 0
 
-local function swap( i, j )
-  b[i], b[j] = b[j], b[i]
-end
-
-local function reset()
-  print( "changing coroutine" )
-  step = coroutine.wrap( twintree.buildIncremental )
-  print( "swapping" )
-  for i = 1, 10000 do
-    swap( i, math.random( 1, 10000 ) )
-  end
-  
-  pointList = nil
-  numMapped = 0
-  print( "step" )
-  step( a, b )
-end
-
 local function new()
   pointList = step()
-  numMapped = numMapped + 1
+  numMapped = #pointList / 2
+end
+
+local cx, cy = 0.0, 0.0
+local zoomFactor = 1
+local function zoom( out )
+  cx = cx + 0.5 * ( out - 1 ) / ( out * zoomFactor )
+  cy = cy + 0.5 * ( out - 1 ) / ( out * zoomFactor )
+  zoomFactor = zoomFactor * out
+  love.graphics.setLineWidth( 0.005 / zoomFactor )
 end
 
 local function paint()
+  if not pointList then return end
   local type = type
   --Make sure the whole point list consists of numbers!
   --We use the __call metamethod in non-number elements to coerce to numbers.
   --TODO: make this more generic, maybe amenable to FFI types.
   for i = 1, #pointList do
-    if type( pointList[i] ) ~= 'number' then pointList[i] = pointList[i]() end 
+    if type( pointList[i] ) ~= 'number' then pointList[i] = pointList[i]( pointList[i] ) end 
   end
   
   --print( "Points: " )
@@ -50,30 +42,34 @@ local function paint()
   
   love.graphics.setCanvas( canvas )
   love.graphics.clear()
-  love.graphics.setColor( 1, 1, 1, 0.5 )
-  love.graphics.print( numMapped )
+  love.graphics.print( ("%d\n%4.2f\n%4.2f\n%4.2f"):format( numMapped, cx, cy, zoomFactor ) )
   love.graphics.push()
   love.graphics.scale( love.graphics.getWidth(), love.graphics.getHeight() )
   love.graphics.translate( 0, 1 )
   love.graphics.scale( 1, -1 )
-  love.graphics.points( pointList )
+  love.graphics.scale( zoomFactor, zoomFactor )
+  love.graphics.translate( -cx, -cy )
+
+  love.graphics.setColor( 1, 1, 1, 0.3 )
+  love.graphics.line( 0,0, 1,0 )
+  love.graphics.line( 0,0, 0,1 )
+  love.graphics.line( 0, 0, 1, 1 )
   love.graphics.line( pointList )
+  love.graphics.setColor( 1, 0, 0, 0.1 * zoomFactor )
+  love.graphics.points( pointList )
   love.graphics.pop()
   love.graphics.setCanvas()
 end
 
-function love.wheelmoved()
-  for i = 1, 3 do new() end
+function love.wheelmoved( x, y )
+  zoom( ( y > 0 ) and 1.01 or 0.99 )
   paint()
- --[[ for i = 1, #sb do
-    print( i, sb[i], dy[i] )
-  end]]
 end
 
 function love.mousepressed()
-  --[[for i = 1, #sb do
-    print( i, sb[i] )
-  end]]
+  --pointList = twintree.flat( twintree.build( 10000, a, b ) )
+  --numMapped = #pointList / 2
+  paint()
 end
 
 function love.draw()
@@ -82,11 +78,27 @@ function love.draw()
   love.graphics.draw( canvas )
 end
 
-function love.keypressed()
-  print( "pressed key!" )
-  return reset() and love.wheelmoved()
+function love.update( dt )
+  local repaint = false
+  if love.keyboard.isScancodeDown "r" then repaint = true; new() end
+  if love.keyboard.isScancodeDown "a" then repaint = true; cx = cx - dt * 0.1 / math.sqrt( zoomFactor ) end
+  if love.keyboard.isScancodeDown "d" then repaint = true; cx = cx + dt * 0.1 / math.sqrt( zoomFactor ) end
+  if love.keyboard.isScancodeDown "w" then repaint = true; cy = cy + dt * 0.1 / math.sqrt( zoomFactor ) end
+  if love.keyboard.isScancodeDown "s" then repaint = true; cy = cy - dt * 0.1 / math.sqrt( zoomFactor ) end
+  if love.keyboard.isScancodeDown "q" then repaint = true; zoom( 1 + dt ) end
+  if love.keyboard.isScancodeDown "e" then repaint = true; zoom( 1 - dt ) end
+  if repaint then return paint() end
+end
+
+function love.keypressed( key, code, isrepeat)
+  return paint()
 end
 
 function love.load()
-  love.graphics.setLineWidth( 0.001 )
+  --pointList = twintree.flat( twintree.build( 10000, a, b ) )
+  --numMapped = #pointList / 2
+  new()
+  love.graphics.setPointSize( 3 )
+  love.graphics.setLineWidth( 0.005 )
+  paint()
 end

twintree.lua

@@ -47,6 +47,8 @@ local function insert( aTree, aSeq, aVals, bTree, bSeq, bVals )
     end
   end
   
+  --print( "Inserting element in tree:", aIdx, aVal, bIdx, bVal )
+
   --Insert elements into tree.
   aTree[treeIdx], bTree[treeIdx] = aVal, bVal