python3 script.py，命令行中的输出为obj中平面的数量，与1.中的decimal设置有关结果图(lenOfRGBs == 50)：
a. decimal(Line 32)，越小，平面数量越少 b. lenOfRGBs(Line 91)，越小，使用的png中的颜色越少，注释的话使用png中全部颜色
如何对应平面和png中的颜色，暂无办法 因此目前修改后的obj不好看
.obj example:
obj&color.zip
| from unicodedata import decimal | |
| from PIL import Image | |
| objFilePath = "obj&color/monu1.vox.obj" | |
| pngFilePath = "obj&color/monu1.vox.png" | |
| mtlFilePath = "obj&color/monu1.vox.mtl" | |
| def loadPng(): | |
| image = Image.open(pngFilePath) | |
| pixels = image.load() | |
| rgbs = [] | |
| for x in range(image.size[0]): | |
| rgbs.append(pixels[x, 0]) | |
| return rgbs | |
| def writeMtl(): | |
| rgbs = loadPng() | |
| with open(mtlFilePath, "w") as w: | |
| for i, rgb in enumerate(rgbs): | |
| w.write("newmtl mtl{}\n".format(i)) | |
| w.write("Kd {} {} {}\n".format(rgb[0], rgb[1], rgb[2])) | |
| w.write("Ks 0.50 0.50 0.50\n") | |
| w.write("\n") | |
| return len(rgbs) | |
| def calSurface(v1, v2, v3): | |
| a = (v2[1] - v1[1]) * (v3[2] - v1[2]) - (v2[2] - v1[2]) * (v3[1] - v1[1]) | |
| b = (v2[2] - v1[2]) * (v3[0] - v1[0]) - (v2[0] - v1[0]) * (v3[2] - v1[2]) | |
| c = (v2[0] - v1[0]) * (v3[1] - v1[1]) - (v2[1] - v1[1]) * (v3[0] - v1[0]) | |
| d = -(a * v1[0] + b * v1[1] + c * v1[2]) | |
| # remained decimal digits, the less decimal the less surfaces | |
| decimal = 2 | |
| a, b, c, d = round(a, decimal), round(b, decimal), round(c, decimal), round(d, decimal) | |
| if a == -0.0: a = 0.0 | |
| if b == -0.0: b = 0.0 | |
| if c == -0.0: c = 0.0 | |
| if d == -0.0: d = 0.0 | |
| return "#".join([str(a), str(b), str(c), str(d)]) | |
| def readObj(): | |
| fs, vs, fcnt, vcnt = {}, {}, 0, 1 # vcnt is the number of vertices, start with 1 | |
| surfaces, revSurfaces = {}, {} # a*x + b*y + c*z = d => <i, str(a#b#c#d)> | |
| with open(objFilePath, "r") as r: | |
| for i, line in enumerate(r.readlines()): | |
| strs = line.split(" ") | |
| if strs[0] == "f": | |
| v1, v2, v3 = int(strs[1].split("/")[0]), int(strs[2].split("/")[0]), int(strs[3].split("/")[0]) | |
| fs[i] = [fcnt, v1, v2, v3] | |
| fcnt += 1 | |
| if strs[0] == "v": | |
| vs[vcnt] = (float(strs[1]), float(strs[2]), float(strs[3])) | |
| vcnt += 1 | |
| newFs = {} | |
| for i, ps in fs.items(): | |
| v1, v2, v3 = vs[ps[1]], vs[ps[2]], vs[ps[3]] | |
| surface = calSurface(v1, v2, v3) | |
| surfaces[i] = surface | |
| if surface not in revSurfaces: revSurfaces[surface] = [i] | |
| else: revSurfaces[surface].append(i) | |
| newFs[i] = [ps[0], surface] | |
| print(len(revSurfaces)) | |
| return fs, newFs, surfaces, revSurfaces | |
| def rewriteObj(lenOfRGBs): | |
| fs, newFs, surfaces, revSurfaces = readObj() | |
| # gap = len(fs) // lenOfRGBs | |
| gap_ = len(revSurfaces) // lenOfRGBs | |
| surface2mtlindex = {} | |
| for i, (fcnt, surface) in newFs.items(): | |
| if surface not in surface2mtlindex: | |
| l = len(surface2mtlindex) | |
| if l // gap_ < lenOfRGBs: | |
| surface2mtlindex[surface] = l // gap_ | |
| else: | |
| surface2mtlindex[surface] = lenOfRGBs - 1 | |
| with open(objFilePath, "r") as r: | |
| with open("obj&color/monu1.vox.new.obj", "w") as w: | |
| for i, line in enumerate(r.readlines()): | |
| # if i in fs and fs[i][0] % gap == 0 and fs[i][0] // gap < lenOfRGBs: | |
| # w.write("usemtl mtl{}\n".format(fs[i][0] // gap)) | |
| if i in newFs: | |
| # printfile(i, newFs[i], surface2mtlindex[newFs[i][1]]) | |
| with open("surface.txt", "a") as a: | |
| a.write("{} {} {}\n".format(i, newFs[i], surface2mtlindex[newFs[i][1]])) | |
| w.write("usemtl mtl{}\n".format(surface2mtlindex[newFs[i][1]])) | |
| w.write(line) | |
| if __name__ == "__main__": | |
| lenOfRGBs = writeMtl() # total colors of .png | |
| lenOfRGBs = 50 # how many RGBs used in one mtl file, options, to make your obj less color... | |
| rewriteObj(lenOfRGBs) |
