Exact reimplementation of "old" C algo in LUA

pulsetunnel.lua

@@ -13,10 +13,21 @@ red = {}
 green = {}
 blue = {}
 
+tmpRed = {}
+tmpGreen = {}
+tmpBlue = {}
+
+function weighted_avg(array, centerIndex)
+  return 0.2 * array[centerIndex - 1] +
+         0.6 * array[centerIndex] +
+         0.2 * array[centerIndex + 1]
+end
+
 function periodic()
   local redEnergy = get_energy_in_band(0, 400);
   local greenEnergy = get_energy_in_band(400, 4000);
   local blueEnergy = get_energy_in_band(4000, 22000);
+  local centerIndex = 2 * center_module;
 
   maxRedEnergy = maxRedEnergy * COOLDOWN_FACTOR
   if redEnergy > maxRedEnergy then
@@ -34,22 +45,28 @@ function periodic()
   end
 
   -- move the color buffers on by one in each direction
-  for i = 2,center_module,1 do
+  for i = 2,centerIndex,1 do
-    red[i-1]   = red[i]
+    tmpRed[i-1]   = tmpRed[i]
-    green[i-1] = green[i]
+    tmpGreen[i-1] = tmpGreen[i]
-    blue[i-1]  = blue[i]
+    tmpBlue[i-1]  = tmpBlue[i]
   end
 
-  for i = num_modules-1,center_module,-1 do
+  for i = #tmpRed-1,centerIndex,-1 do
-    red[i+1]   = red[i]
+    tmpRed[i+1]   = tmpRed[i]
-    green[i+1] = green[i]
+    tmpGreen[i+1] = tmpGreen[i]
-    blue[i+1]  = blue[i]
+    tmpBlue[i+1]  = tmpBlue[i]
   end
 
   -- set the new value for the center module
-  red[center_module] = redEnergy / maxRedEnergy
+  tmpRed[centerIndex] = redEnergy / maxRedEnergy
-  green[center_module] = greenEnergy / maxGreenEnergy
+  tmpGreen[centerIndex] = greenEnergy / maxGreenEnergy
-  blue[center_module] = blueEnergy / maxBlueEnergy
+  tmpBlue[centerIndex] = blueEnergy / maxBlueEnergy
+
+  for i = 1,num_modules do
+    red[i] = weighted_avg(tmpRed, 2*i)
+    green[i] = weighted_avg(tmpGreen, 2*i)
+    blue[i] = weighted_avg(tmpBlue, 2*i)
+  end
 
   -- return the 3 color arrays
   return red, green, blue
@@ -65,6 +82,12 @@ function init(nmod, cmod)
     blue[i] = 0
   end
 
+  for i = 1,2*(nmod+1) do
+    tmpRed[i] = 0
+    tmpGreen[i] = 0
+    tmpBlue[i] = 0
+  end
+
   -- don't use fading
   return 0
 end