import_obj.py

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# <pep8 compliant>

# Script copyright (C) Campbell Barton
# Contributors: Campbell Barton, Jiri Hnidek, Paolo Ciccone

"""
This script imports a Wavefront OBJ files to Blender.

Usage:
Run this script from "File->Import" menu and then load the desired OBJ file.
Note, This loads mesh objects and materials only, nurbs and curves are not supported.

http://wiki.blender.org/index.php/Scripts/Manual/Import/wavefront_obj
"""

import array
import os
import time
import bpy
import mathutils

from bpy_extras.io_utils import unpack_list
from bpy_extras.image_utils import load_image
from bpy_extras.wm_utils.progress_report import ProgressReport


def line_value(line_split):
    """
    Returns 1 string representing the value for this line
    None will be returned if there's only 1 word
    """
    length = len(line_split)
    if length == 1:
        return None

    elif length == 2:
        return line_split[1]

    elif length > 2:
        return b' '.join(line_split[1:])


def obj_image_load(context_imagepath_map, line, DIR, recursive, relpath):
    """
    Mainly uses comprehensiveImageLoad
    But we try all space-separated items from current line when file is not found with last one
    (users keep generating/using image files with spaces in a format that does not support them, sigh...)
    Also tries to replace '_' with ' ' for Max's exporter replaces spaces with underscores.
    """
    filepath_parts = line.split(b' ')
    image = None
    for i in range(-1, -len(filepath_parts), -1):
        imagepath = os.fsdecode(b" ".join(filepath_parts[i:]))
        image = context_imagepath_map.get(imagepath, ...)
        if image is ...:
            image = load_image(imagepath, DIR, recursive=recursive, relpath=relpath)
            if image is None and "_" in imagepath:
                image = load_image(imagepath.replace("_", " "), DIR, recursive=recursive, relpath=relpath)
            if image is not None:
                context_imagepath_map[imagepath] = image
                break;

    if image is None:
        imagepath = os.fsdecode(filepath_parts[-1])
        image = load_image(imagepath, DIR, recursive=recursive, place_holder=True, relpath=relpath)
        context_imagepath_map[imagepath] = image

    return image


def create_materials(filepath, relpath,
                     material_libs, unique_materials,
                     use_image_search, float_func):
    """
    Create all the used materials in this obj,
    assign colors and images to the materials from all referenced material libs
    """
    from math import sqrt
    from bpy_extras import node_shader_utils

    DIR = os.path.dirname(filepath)
    context_material_vars = set()

    # Don't load the same image multiple times
    context_imagepath_map = {}

    nodal_material_wrap_map = {}

    def load_material_image(blender_material, mat_wrap, context_material_name, img_data, line, type):
        """
        Set textures defined in .mtl file.
        """
        map_options = {}

        curr_token = []
        for token in img_data[:-1]:
            if token.startswith(b'-') and token[1:].isalpha():
                if curr_token:
                    map_options[curr_token[0]] = curr_token[1:]
                curr_token[:] = []
            curr_token.append(token)
        if curr_token:
            map_options[curr_token[0]] = curr_token[1:]

        # Absolute path - c:\.. etc would work here
        image = obj_image_load(context_imagepath_map, line, DIR, use_image_search, relpath)

        map_offset = map_options.get(b'-o')
        map_scale = map_options.get(b'-s')

        def _generic_tex_set(nodetex, image, texcoords, translation, scale):
            nodetex.image = image
            nodetex.texcoords = texcoords
            if translation is not None:
                nodetex.translation = translation
            if scale is not None:
                nodetex.scale = scale

        # Adds textures for materials (rendering)
        if type == 'Kd':
            _generic_tex_set(mat_wrap.base_color_texture, image, 'UV', map_offset, map_scale)

        elif type == 'Ka':
            # XXX Not supported?
            print("WARNING, currently unsupported ambient texture, skipped.")

        elif type == 'Ks':
            _generic_tex_set(mat_wrap.specular_texture, image, 'UV', map_offset, map_scale)

        elif type == 'Ke':
            # XXX Not supported?
            print("WARNING, currently unsupported emit texture, skipped.")

        elif type == 'Bump':
            bump_mult = map_options.get(b'-bm')
            bump_mult = float(bump_mult[0]) if (bump_mult and len(bump_mult[0]) > 1) else 1.0
            mat_wrap.normalmap_strength_set(bump_mult)

            _generic_tex_set(mat_wrap.normalmap_texture, image, 'UV', map_offset, map_scale)

        elif type == 'D':
            _generic_tex_set(mat_wrap.transmission_texture, image, 'UV', map_offset, map_scale)

        elif type == 'disp':
            # XXX Not supported?
            print("WARNING, currently unsupported displacement texture, skipped.")
            # ~ mat_wrap.bump_image_set(image)
            # ~ mat_wrap.bump_mapping_set(coords='UV', translation=map_offset, scale=map_scale)

        elif type == 'refl':
            map_type = map_options.get(b'-type')
            if map_type and map_type != [b'sphere']:
                print("WARNING, unsupported reflection type '%s', defaulting to 'sphere'"
                      "" % ' '.join(i.decode() for i in map_type))

            _generic_tex_set(mat_wrap.base_color_texture, image, 'Reflection', map_offset, map_scale)
            mat_wrap.base_color_texture.projection = 'SPHERE'

        else:
            raise Exception("invalid type %r" % type)

    def finalize_material(context_material, context_material_vars, spec_colors, emit_colors,
                          do_highlight, do_reflection, do_transparency, do_glass):
        # Finalize previous mat, if any.
        if context_material:
            if "specular" in context_material_vars:
                # XXX This is highly approximated, not sure whether we can do better...
                # TODO: Find a way to guesstimate best value from diffuse color...
                # IDEA: Use standard deviation of both spec and diff colors (i.e. how far away they are
                #       from some grey), and apply the the proportion between those two as tint factor?
                spec = sum(spec_colors) / 3.0
                # ~ spec_var = math.sqrt(sum((c - spec) ** 2 for c in spec_color) / 3.0)
                # ~ diff = sum(context_mat_wrap.base_color) / 3.0
                # ~ diff_var = math.sqrt(sum((c - diff) ** 2 for c in context_mat_wrap.base_color) / 3.0)
                # ~ tint = min(1.0, spec_var / diff_var)
                context_mat_wrap.specular = spec
                context_mat_wrap.specular_tint = 0.0
                if "roughness" not in context_material_vars:
                    context_mat_wrap.roughness = 0.0


            emit_value = sum(emit_colors) / 3.0