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Fix T45766: Exported OBJ/MTL files do not include emissive lighting parameters. 

ke/map_ke are not official .mtl specs, but seem to be rather common extension.
map_ke was added three years ago to exporter only, this commit finishes the work
by adding ke/map_ke to importer, and ke to exporter.

NOTES:
* mtl ke is a color, while in Blender emit is only a factor, using diffuse color.
  this implies there is some loss of data during import here.
* I do not have the slightest idea about the range for ke values, so for now assuming
  a direct matching of Blender's emit value.
This commit is contained in:
Bastien Montagne 2015-08-13 12:04:04 +02:00
parent 4c142e5920
commit 94c9c4ee33
Notes: blender-bot 2023-02-14 08:46:22 +01:00 
Referenced by issue blender/blender#45766, Exported OBJ/MTL files do not include emissive lighting parameters
2 changed files with 28 additions and 1 deletions
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3
io_scene_obj/export_obj.py
View File

@ -90,6 +90,9 @@ def write_mtl(scene, filepath, path_mode, copy_set, mtl_dict):
fw('Ka %.6f %.6f %.6f\n' % (mat.ambient, mat.ambient, mat.ambient)) # Do not use world color!
fw('Kd %.6f %.6f %.6f\n' % (mat.diffuse_intensity * mat.diffuse_color)[:]) # Diffuse
fw('Ks %.6f %.6f %.6f\n' % (mat.specular_intensity * mat.specular_color)[:]) # Specular
# Emission, not in original MTL standard but seems pretty common, see T45766.
# XXX Blender has no color emission, it's using diffuse color instead...
fw('Ke %.6f %.6f %.6f\n' % (mat.emit * mat.diffuse_color)[:])
if hasattr(mat, "raytrace_transparency") and hasattr(mat.raytrace_transparency, "ior"):
fw('Ni %.6f\n' % mat.raytrace_transparency.ior) # Refraction index
else:

26
io_scene_obj/import_obj.py
View File

@ -120,6 +120,14 @@ def create_materials(filepath, relpath,
mtex.texture_coords = 'UV'
mtex.use_map_color_spec = True
elif type == 'Ke':
mtex = blender_material.texture_slots.add()
mtex.use_map_color_diffuse = False
mtex.texture = texture
mtex.texture_coords = 'UV'
mtex.use_map_emit = True
elif type == 'Bump':
mtex = blender_material.texture_slots.add()
mtex.use_map_color_diffuse = False
@ -190,6 +198,7 @@ def create_materials(filepath, relpath,
do_glass = False
do_fresnel = False
do_raytrace = False
emit_colors = [0.0, 0.0, 0.0]
# print('\t\tloading mtl: %e' % mtlpath)
context_material = None
@ -203,8 +212,14 @@ def create_materials(filepath, relpath,
line_id = line_split[0].lower()
if line_id == b'newmtl':
# Finalize preview mat, if any.
# Finalize previous mat, if any.
if context_material:
emit_value = sum(emit_colors) / 3.0
if emit_value > 1e-6:
# We have to adapt it to diffuse color too...
emit_value /= sum(context_material.diffuse_color) / 3.0
context_material.emit = emit_value
if not do_ambient:
context_material.ambient = 0.0
@ -243,6 +258,7 @@ def create_materials(filepath, relpath,
context_material = unique_materials.get(context_material_name)
context_material_vars.clear()
emit_colors[:] = [0.0, 0.0, 0.0]
do_ambient = True
do_highlight = False
do_reflection = False
@ -267,6 +283,10 @@ def create_materials(filepath, relpath,
context_material.specular_color = (
float_func(line_split[1]), float_func(line_split[2]), float_func(line_split[3]))
context_material.specular_intensity = 1.0
elif line_id == b'ke':
# We cannot set context_material.emit right now, we need final diffuse color as well for this.
emit_colors[:] = [
float_func(line_split[1]), float_func(line_split[2]), float_func(line_split[3])]
elif line_id == b'ns':
context_material.specular_hardness = int((float_func(line_split[1]) * 0.51) + 1)
elif line_id == b'ni': # Refraction index (between 1 and 3).
@ -351,6 +371,10 @@ def create_materials(filepath, relpath,
img_filepath = line_value(line.split())
if img_filepath:
load_material_image(context_material, context_material_name, img_filepath, 'Kd')
elif line_id == b'map_ke':
img_filepath = line_value(line.split())
if img_filepath:
load_material_image(context_material, context_material_name, img_filepath, 'Ke')
elif line_id in {b'map_bump', b'bump'}: # 'bump' is incorrect but some files use it.
img_filepath = line_value(line.split())
if img_filepath: