always convert image to RGB before checking RGB colors

[illwieckz]

Previously, Sloth was assuming the given addition texture was an RGB one. By the way, some PNG crusher use index PNG abilities to losslessly save space when possible. Because of that, Sloth crashes.

This code is faulty, it crashes on if not rgb[0] == rgb[1] == rgb[2]:

if shader["addition"]:
	img = Image.open(shader["abspath"]+os.path.sep+shader["addition"]+shader["ext"]["addition"], "r")

	gray = ( img.mode in ("L", "LA") )

	# check for RGB images with no actual non-gray color
	if not gray:
		colors = img.getcolors(maxcolors = 256)
		if colors:
			gray = True
			for _, rgb in colors:
				if not rgb[0] == rgb[1] == rgb[2]:
					gray = False
					break

	shader["meta"]["additionGrayscale"] = gray

Here is some experiments I did:

In [1]: from PIL import Image
In [2]: img = Image.open("…/tex-pk02_src.dpkdir/textures/shared_pk02_src/wall02c_a.png")
In [7]: _, rgb = img.getcolors(maxcolors = 256)[0]
In [8]: rgb
Out[8]: 0
In [9]: rgb[0]
TypeError                                 Traceback (most recent call last)
----> 1 rgb[0]

TypeError: 'int' object is not subscriptable

In [13]: img = Image.open("…/tex-pk02_source.pk3dir/textures/shared_pk02_src/wall02c_a.tga")
In [14]: img.getcolors()[0]
Out[14]: (44, (255, 255, 255))
In [15]: img = Image.open("…/tex-pk02_src.dpkdir/textures/shared_pk02_src/wall02c_a.png")
In [16]: img.getcolors()[0]
Out[16]: (23, 0)
In [17]: img = img.convert("RGB")
In [18]: img.getcolors()[0]
Out[18]: (44, (255, 255, 255))
In [19]: img = Image.open("…/tex-pk02_src.dpkdir/textures/shared_pk02_src/wall02c_a.png").convert("RGB")
In [20]: img.getcolors()[0]
Out[20]: (44, (255, 255, 255))
In [24]: _, rgb = img.getcolors()[0]
In [25]: rgb
Out[25]: (255, 255, 255)

The fix is easy:

if shader["addition"]:
-	img = Image.open(shader["abspath"]+os.path.sep+shader["addition"]+shader["ext"]["addition"], "r")
+	img = Image.open(shader["abspath"]+os.path.sep+shader["addition"]+shader["ext"]["addition"], "r").convert("RGB")

	gray = ( img.mode in ("L", "LA") )

	# check for RGB images with no actual non-gray color
	if not gray:
		colors = img.getcolors(maxcolors = 256)
		if colors:
			gray = True
			for _, rgb in colors:
				if not rgb[0] == rgb[1] == rgb[2]:
					gray = False
					break

	shader["meta"]["additionGrayscale"] = gray

[Viech]

Wouldn't it make more sense to convert the image after the gray = ( img.mode in ("L", "LA") ) check? I didn't test, but from a distance it looks like that check can never succeed if the image was converted before.

[illwieckz]

fixed

[illwieckz]

for documentation purpose, that was how looked like the error before that fix:

Traceback (most recent call last):
  File "…/sloth.py", line 1108, in <module>
    sg.generateSet(path, setname = a.root, cutextension = a.strip)
  File "…/sloth.py", line 648, in generateSet
    self.__analyzeMaps(shader)
  File "…/sloth.py", line 432, in __analyzeMaps
    if not rgb[0] == rgb[1] == rgb[2]:
TypeError: 'int' object is not subscriptable

[Viech]

Sorry, I didn't pay any more attention to this since my last comment. The change looks good with the new order of operations.

[illwieckz]

Thanks for the review. It looks like I can't merge it myself, can you do it?