修改png并应用到obj与voxel

readme.md

• 经查明，发现大狗老师应该是导出时出问题了，所以没有得到这个mtl文件，但这个mtl文件也很简单，直接添加一个即可

newmtl palette
illum 1
Ka 0.000 0.000 0.000
Kd 1.000 1.000 1.000
Ks 0.000 0.000 0.000
map_Kd monu1.vox.png # 可以换成其他图片。

usage

0. python3 script.py -h

输入：（都在script.py同目录，懒得弄相对路径了。。）

• inputpng的路径（即从MagicaVoxel导出的png，可以省略
• outputpng的路径（不可省略
• outputmtl的路径（不可省略
• type（可以省略，默认random
• replace（可以没有，有的话就是**-r fromcolor tocolor**，即将颜色从前者修改为后者

Usage: python3 script.py -i <inputpng> -o <outputpng> -m <outputmtl> -t <type>(default random) -r <fromcolor> <tocolor>(hex start with 0x) -s(show inputpng)
Example1: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -t random
Example2: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -r 0x839aa9 0xff0000
type: random, deeper, shallower

1. 随机生成palette png (256x1)

Example: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -t random

2. 根据导出的palette png进行分析并修改

Example: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -t random 根据之前的palette png文件让obj的颜色变得更深/浅，每次变化的gap可修改script.py中Line6/7

3. 查看输入png中的颜色

Example: python3 script.py -i monu1.vox.png -s

4. 将之前png中的颜色修改为自己想要的颜色

Example: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -r 0x839aa9 0xff0000 如将上图中的0x839aa9修改至0xff0000（红色）

before:

after python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -r 0x893aa9 0xff0000:

5. 打开obj即可查看修改后的效果

before:

after python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -t random:

6. 将修改后的png应用到voxel中

将上面生成的palette png导入到MagicaVoxel中，如下图所示：

script.py

from PIL import Image
import random, sys, getopt, os

from hamcrest import none

DEEP = 20
SHALLOW = 20
SHOW_INPUTPNG = False

def writeMtl(opng, omtl):
    with open(omtl, "w") as w:
        w.write('''newmtl palette
illum 1
Ka 0.000 0.000 0.000
Kd 1.000 1.000 1.000
Ks 0.000 0.000 0.000
map_Kd {}\n'''.format(opng))

def loadPng(ipng):
    if ipng is None:
        rgbas = []
        for x in range(256):
            rgbas.append((255, 255, 255, 255))
        return rgbas
    if not os.path.isfile(ipng):
        print("{} not found".format(ipng))
        sys.exit(1)
    image = Image.open(ipng)
    pixels = image.load()
    rgbas = []
    for x in range(image.size[0]):
        rgbas.append(pixels[x, 0])
    return rgbas

def generatePng(ipng, opng, omtl, type_, replace):
    irgbas = loadPng(ipng)
    oimg = Image.new('RGBA', (256, 1), (0, 0, 0, 0))

    if replace is not None:
        frgba = str2rgba(replace[0])
        trgba = str2rgba(replace[1])
        for i in range(oimg.size[0]):
            rgba = tuple(irgbas[i])
            if rgba[0] == frgba[0] and rgba[1] == frgba[1] and rgba[2] == frgba[2]:
                oimg.putpixel((i, 0), (trgba[0], trgba[1], trgba[2], rgba[3]))
            else:
                oimg.putpixel((i, 0), rgba)
    else:
        if type_ == "random":
            for i in range(oimg.size[0]):
                oimg.putpixel((i, 0), (random.randint(0, 255), random.randint(0, 255), random.randint(0, 255), 255))
        elif type_ == "deeper":
            for i in range(oimg.size[0]):
                rgba = tuple(max(0, x - DEEP) for x in irgbas[i])
                oimg.putpixel((i, 0), rgba)
        elif type_ == "shallower":
            for i in range(oimg.size[0]):
                rgba = tuple(min(255, x + SHALLOW) for x in irgbas[i])
                oimg.putpixel((i, 0), rgba)
        else:
            usage()
            sys.exit(1)

    oimg.save(opng)
    writeMtl(opng, omtl)

def usage():
    print("Usage: python3 script.py -i <inputpng> -o <outputpng> -m <outputmtl> -t <type>(default random) -r <fromcolor> <tocolor>(hex start with 0x) -s(show inputpng)")
    print("Example1: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -t random")
    print("Example2: python3 script.py -i monu1.vox.png -o monu1.vox.png -m monu1.vox.mtl -r 0x839aa9 0xff0000")
    print("type: random, deeper, shallower")

def str2rgba(s):
    if s[0:2] != "0x":
        return None
    s = s[2:]
    if len(s) != 6:
        return None
    try:
        r = int(s[0:2], 16)
        g = int(s[2:4], 16)
        b = int(s[4:6], 16)
    except ValueError:
        return None
    return (r, g, b, 255)

def rgba2str(rgba):
    return "0x{:02x}{:02x}{:02x}".format(rgba[0], rgba[1], rgba[2])

if __name__ == "__main__":
    try:
        opts, args = getopt.getopt(sys.argv[1:],"hi:o:m:t:rs",["ipng=","opng=","omtl=","type=","replace=","showpng="])
    except getopt.GetoptError:
        print(getopt.GetoptError)
        usage()
        sys.exit(2)
    ipng, opng, omtl, type_, replace = None, None, None, None, None
    for opt, arg in opts:
        if opt == "-h":
            usage()
            sys.exit()
        elif opt in ("-s", "--showpng"):
            SHOW_INPUTPNG = True
        elif opt in ("-i", "--ipng"):
            ipng = arg
        elif opt in ("-o", "--opng"):
            opng = arg
        elif opt in ("-t", "--type"):
            type_ = arg
        elif opt in ("-m", "--omtl"):
            omtl = arg
        elif opt in ("-r", "--replace"):
            replace = args
    if SHOW_INPUTPNG: # show input png
        rgbas, lcnt = loadPng(ipng), 8
        for i, rgba in enumerate(rgbas):
            print(rgba2str(rgba), end=" ")
            if i % lcnt == lcnt - 1:
                print("")
        sys.exit(0)
    if opng is None or omtl is None:
        print("[ERROR] Please specify outputpng and outputmtl")
        usage()
        sys.exit()
    if replace is not None and len(replace) != 2:
        print("[ERROR] Please specify replace")
        usage()
        sys.exit()
    if replace is not None and (str2rgba(replace[0]) is None or str2rgba(replace[1]) is None):
        print("[ERROR] Please specify replace with hex")
        usage()
        sys.exit()

    if type_ is None: type_ = "random"
    generatePng(ipng, opng, omtl, type_, replace)