Start image compression

assets/img2array.py

@@ -16,6 +16,7 @@ def printHelp():
   print("  -nS     use the name S for the texture (defaut: \"texture\")")
   print("  -pT     use palette from file T and indexed colors (otherwise direct colors)")
   print("  -5      use 565 format instead of RGB8")
+  print("  -c      compress (4 bpp, 16 color palette), only with -pT")
   print("  -t      transpose (store by columns)")
   print("");
   print("by Miloslav \"drummyfish\" Ciz")
@@ -37,6 +38,7 @@ OUT_WIDTH = 64
 OUT_HEIGHT = 64
 USE_565 = False
 TRANSPOSE = False
+COMPRESS = False
 
 for s in sys.argv:
   if s [:2] == "-x":
@@ -54,9 +56,14 @@ for s in sys.argv:
     USE_PALETTE = True
   elif s[:2] == "-t":
     TRANSPOSE = True
+  elif s[:2] == "-c":
+    COMPRESS = True
   else:
     FILENAME = s
 
+if not USE_PALETTE:
+  COMPRESS = False
+
 imageArray = []
 paletteColors = []
 paletteArray = []
@@ -83,6 +90,22 @@ if USE_PALETTE > 0:
 image2 = Image.new("RGB",(OUT_WIDTH,OUT_HEIGHT),color="white")
 pixels2 = image2.load()
 
+def findClosestColor(pixel,paletteColors):
+  closestIndex = 0     
+  closestDiff = 1024
+
+  # find the index of the closest color:
+
+  for i in range(len(paletteColors)):
+    c = paletteColors[i]
+    diff = abs(pixel[0] - c[0]) + abs(pixel[1] - c[1]) + abs(pixel[2] - c[2])
+
+    if diff < closestDiff:
+      closestIndex = i
+      closestDiff = diff
+
+  return closestIndex
+
 for y in range(OUT_HEIGHT):
   for x in range(OUT_WIDTH):
     x2 = y if TRANSPOSE else x
@@ -95,19 +118,7 @@ for y in range(OUT_HEIGHT):
     pixel = pixels[coord]
 
     if USE_PALETTE:
-      closestIndex = 0     
-      closestDiff = 1024
-
-      # find the index of the closest color:
-
-      for i in range(len(paletteColors)):
-        c = paletteColors[i]
-        diff = abs(pixel[0] - c[0]) + abs(pixel[1] - c[1]) + abs(pixel[2] - c[2])
-
-        if diff < closestDiff:
-          closestIndex = i
-          closestDiff = diff
-
+      closestIndex = findClosestColor(pixel,paletteColors)     
       imageArray.append(closestIndex)
       pixels2[x,y] = paletteColors[closestIndex]
     else:
@@ -122,6 +133,46 @@ for y in range(OUT_HEIGHT):
 
 #-----------------------
 
+def compressImageArray(a):
+  result = []
+
+  reducedPalette = []
+
+  histogram = [0 for i in range(256)]
+
+  for c in a:
+    histogram[c] += 1
+
+  for i in range(16):
+    maxValue = 0
+    maxIndex = 0
+
+    for j in range(256):
+      if histogram[j] > maxValue:
+        maxValue = histogram[j]
+        maxIndex = j
+
+    reducedPalette.append(maxIndex)
+    histogram[maxIndex] = 0
+
+  paletteMap = [findClosestColor(paletteColors[i],[paletteColors[j] for j in reducedPalette]) for i in range(256)]
+
+  oneByte = 0
+  byteCount = 0
+
+  for c in a:
+    if byteCount % 2 == 0:
+      oneByte = paletteMap[c]
+    else:
+      oneByte = (oneByte << 4) | paletteMap[c]
+      result.append(oneByte)
+
+    byteCount += 1
+
+  result = reducedPalette + result
+
+  return result
+
 def printArray(array, name, sizeString, dataType="const uint8_t"):
   print(dataType + " " + name + "[" + sizeString + "] = {")
   arrayString = ""
@@ -153,6 +204,9 @@ if USE_PALETTE:
 print("#define " + NAME.upper() + "_TEXTURE_WIDTH " + str(OUT_WIDTH))
 print("#define " + NAME.upper() + "_TEXTURE_HEIGHT " + str(OUT_HEIGHT))
 print("")
+  
+if COMPRESS:
+  imageArray = compressImageArray(imageArray)    
 
 printArray(imageArray,NAME + "Texture",str(len(imageArray)))