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Fix: Updated sdf_exporter.py based on review feedback
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Signed-off-by: mahit2609 <[email protected]>
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@mahit2609
mahit2609 committed Jan 25, 2025
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Showing 1 changed file with 135 additions and 131 deletions.
266 changes: 135 additions & 131 deletions examples/scripts/blender/sdf_exporter.py
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import xml.etree.ElementTree as ET
from os import path
from xml.dom import minidom

import bpy
import os.path
from bpy_extras.io_utils import ImportHelper
from bpy.props import StringProperty, BoolProperty
from bpy.props import StringProperty
from bpy.types import Operator
from bpy_extras.io_utils import ImportHelper

import xml.etree.ElementTree as ET
from xml.dom import minidom
# Tested Blender version: 4.2/4.3

########################################################################################################################
### Exports model.dae of the scene with textures, its corresponding model.sdf file, and a default model.config file ####
########################################################################################################################
def export_sdf(prefix_path):
dae_filename = 'model.dae'
sdf_filename = 'model.sdf'
model_config_filename = 'model.config'
lightmap_filename = 'LightmapBaked.png'
model_name = 'my_model'
meshes_folder_prefix = 'meshes/'


dae_filename = "model.dae"
sdf_filename = "model.sdf"
model_config_filename = "model.config"
lightmap_filename = "LightmapBaked.png"
model_name = "my_model"
meshes_folder_prefix = "meshes/"

# Exports the dae file and its associated textures
bpy.ops.wm.collada_export(filepath=prefix_path+meshes_folder_prefix+dae_filename,
check_existing=False,
filter_blender=False,
filter_image=False,
filter_movie=False,
filter_python=False,
filter_font=False,
filter_sound=False,
filter_text=False,
filter_btx=False,
filter_collada=True,
filter_folder=True,
filemode=8)
bpy.ops.wm.collada_export(
filepath=path.join(prefix_path, meshes_folder_prefix, dae_filename),
check_existing=False,
filter_blender=False,
filter_image=False,
filter_movie=False,
filter_python=False,
filter_font=False,
filter_sound=False,
filter_text=False,
filter_btx=False,
filter_collada=True,
filter_folder=True,
filemode=8,
)

# objects = bpy.context.selected_objects
objects = bpy.context.selectable_objects
mesh_objects = [o for o in objects if o.type == 'MESH']
light_objects = [o for o in objects if o.type == 'LIGHT']
mesh_objects = [o for o in objects if o.type == "MESH"]
light_objects = [o for o in objects if o.type == "LIGHT"]

#############################################
#### export sdf xml based off the scene #####
#############################################
sdf = ET.Element("sdf", attrib={"version": "1.8"})

sdf = ET.Element('sdf', attrib={'version':'1.8'})
model = ET.SubElement(sdf, "model", attrib={"name":"test"})
# 1 model and 1 link
model = ET.SubElement(sdf, "model", attrib={"name": "test"})
static = ET.SubElement(model, "static")
static.text = "true"
link = ET.SubElement(model, "link", attrib={"name":"testlink"})

def get_diffuse_map(material):
"""Helper function to safely get diffuse map from material"""
if not material or not material.use_nodes or not material.node_tree:
return ""

nodes = material.node_tree.nodes
principled = next((n for n in nodes if n.type == 'BSDF_PRINCIPLED'), None)

if not principled:
return ""

base_color = principled.inputs.get('Base Color') or principled.inputs[0]
if not base_color.links:
return ""

link_node = base_color.links[0].from_node
if not hasattr(link_node, 'image') or not link_node.image:
return ""

return link_node.image.name

link = ET.SubElement(model, "link", attrib={"name": "testlink"})
# for each geometry in geometry library add a <visual> tag
for o in mesh_objects:
visual = ET.SubElement(link, "visual", attrib={"name":o.name})
visual = ET.SubElement(link, "visual", attrib={"name": o.name})

geometry = ET.SubElement(visual, "geometry")
mesh = ET.SubElement(geometry, "mesh")
uri = ET.SubElement(mesh, "uri")
uri.text = dae_filename
uri.text = path.join(meshes_folder_prefix, dae_filename)
submesh = ET.SubElement(mesh, "submesh")
submesh_name = ET.SubElement(submesh, "name")
submesh_name.text = o.name

# Material handling

# grab diffuse/albedo map
diffuse_map = ""
if o.active_material is not None:
nodes = o.active_material.node_tree.nodes
principled = next(n for n in nodes if n.type == "BSDF_PRINCIPLED")
if principled is not None:
base_color = principled.inputs["Base Color"]
if len(base_color.links):
link_node = base_color.links[0].from_node
diffuse_map = link_node.image.name

# setup diffuse/specular color
material = ET.SubElement(visual, "material")
diffuse = ET.SubElement(material, "diffuse")
diffuse.text = "1.0 1.0 1.0 1.0"
specular = ET.SubElement(material, "specular")
specular.text = "0.0 0.0 0.0 1.0"
pbr = ET.SubElement(material, "pbr")
metal = ET.SubElement(pbr, "metal")

# Get diffuse map if material exists
if o.active_material:
diffuse_map = get_diffuse_map(o.active_material)
if diffuse_map:
albedo_map = ET.SubElement(metal, "albedo_map")
albedo_map.text = meshes_folder_prefix + diffuse_map

# Lightmap handling
if os.path.isfile(lightmap_filename):
light_map = ET.SubElement(metal, "light_map", attrib={"uv_set":"1"})
light_map.text = meshes_folder_prefix + lightmap_filename
if diffuse_map != "":
albedo_map = ET.SubElement(metal, "albedo_map")
albedo_map.text = path.join(meshes_folder_prefix, diffuse_map)

# for lightmapping, add the UV and turn off casting of shadows
if path.isfile(lightmap_filename):
light_map = ET.SubElement(metal, "light_map", attrib={"uv_set": "1"})
light_map.text = path.join(meshes_folder_prefix, lightmap_filename)

cast_shadows = ET.SubElement(visual, "cast_shadows")
cast_shadows.text = "0"

def add_attenuation_tags(light_tag, blender_light):
"""Helper function to add attenuation tags based on light type"""
attenuation = ET.SubElement(light_tag, "attenuation")

# Range (cutoff distance)
range_tag = ET.SubElement(attenuation, "range")
range_tag.text = str(blender_light.cutoff_distance)

# Linear attenuation factor
range = ET.SubElement(attenuation, "range")
range.text = str(blender_light.cutoff_distance)
linear = ET.SubElement(attenuation, "linear")
linear.text = "1.0" # Default linear attenuation

# Quadratic attenuation factor
linear.text = "1.0"
quadratic = ET.SubElement(attenuation, "quadratic")
quadratic.text = "0.0" # Default quadratic attenuation

# Constant attenuation factor
quadratic.text = "0.0"
constant = ET.SubElement(attenuation, "constant")
constant.text = "1.0" # Default constant attenuation
constant.text = "1.0"


# Export lights
# export lights
for l in light_objects:
blender_light = l.data

if blender_light.type == "POINT":
light = ET.SubElement(link, "light", attrib={"name":l.name, "type":"point"})
light = ET.SubElement(link, "light", attrib={"name": l.name, "type": "point"})
diffuse = ET.SubElement(light, "diffuse")
diffuse.text = f"{blender_light.color.r} {blender_light.color.g} {blender_light.color.b} 1.0"
add_attenuation_tags(light, blender_light)
elif blender_light.type == "SPOT":
light = ET.SubElement(link, "light", attrib={"name":l.name, "type":"spot"})

if blender_light.type == "SPOT":
light = ET.SubElement(link, "light", attrib={"name": l.name, "type": "spot"})
diffuse = ET.SubElement(light, "diffuse")
diffuse.text = f"{blender_light.color.r} {blender_light.color.g} {blender_light.color.b} 1.0"
add_attenuation_tags(light, blender_light)

# Add spot light specific parameters
# note: unsupported <spot> tags in blender
spot = ET.SubElement(light, "spot")
inner_angle = ET.SubElement(spot, "inner_angle")
inner_angle.text = str(blender_light.spot_size * 0.5) # Convert to inner angle
inner_angle.text = str(blender_light.spot_size * 0.5)
outer_angle = ET.SubElement(spot, "outer_angle")
outer_angle.text = str(blender_light.spot_size) # Outer angle
outer_angle.text = str(blender_light.spot_size)
falloff = ET.SubElement(spot, "falloff")
falloff.text = str(blender_light.spot_blend * 10) # Approximate falloff from blend
elif blender_light.type == "SUN":
light = ET.SubElement(link, "light", attrib={"name":l.name, "type":"directional"})
falloff.text = str(blender_light.spot_blend * 10)

if blender_light.type == "SUN":
light = ET.SubElement(link, "light", attrib={"name": l.name, "type": "directional"})
diffuse = ET.SubElement(light, "diffuse")
diffuse.text = f"{blender_light.color.r} {blender_light.color.g} {blender_light.color.b} 1.0"

if blender_light.type in ["SUN", "SPOT"]:
direction = ET.SubElement(light, "direction")
direction.text = f"{l.matrix_world[0][2]} {l.matrix_world[1][2]} {l.matrix_world[2][2]}"

# Common light properties
# unsupported: AREA lights

cast_shadows = ET.SubElement(light, "cast_shadows")
cast_shadows.text = "true"


# todo : bpy.types.light script api lacks an intensity value, possible candidate is energy/power(Watts)?
intensity = ET.SubElement(light, "intensity")
intensity.text = str(blender_light.energy) # Use the light's energy as intensity

# Collision tags
collision = ET.SubElement(link, "collision", attrib={"name":"collision"})
intensity.text = str(blender_light.energy)

## sdf collision tags
collision = ET.SubElement(link, "collision", attrib={"name": "collision"})

geometry = ET.SubElement(collision, "geometry")
mesh = ET.SubElement(geometry, "mesh")
uri = ET.SubElement(mesh, "uri")
uri.text = dae_filename
uri.text = path.join(meshes_folder_prefix, dae_filename)

surface = ET.SubElement(collision, "surface")
contact = ET.SubElement(collision, "contact")
collide_bitmask = ET.SubElement(collision, "collide_bitmask")
contact = ET.SubElement(surface, "contact")
collide_bitmask = ET.SubElement(contact, "collide_bitmask")
collide_bitmask.text = "0x01"

# Write SDF file
xml_string = ET.tostring(sdf, encoding='unicode')
## sdf write to file
xml_string = ET.tostring(sdf, encoding="unicode")
reparsed = minidom.parseString(xml_string)
with open(prefix_path+sdf_filename, "w") as sdf_file:
with open(path.join(prefix_path, sdf_filename), "w") as sdf_file:
sdf_file.write(reparsed.toprettyxml(indent=" "))

# Generate model.config
model = ET.Element('model')
name = ET.SubElement(model, 'name')
##############################
### generate model.config ####
##############################
model = ET.Element("model")
name = ET.SubElement(model, "name")
name.text = model_name
version = ET.SubElement(model, 'version')
version = ET.SubElement(model, "version")
version.text = "1.0"
sdf_tag = ET.SubElement(model, "sdf", attrib={"version":"1.8"})
sdf_tag = ET.SubElement(model, "sdf", attrib={"version": "1.8"})
sdf_tag.text = sdf_filename

author = ET.SubElement(model, 'author')
name = ET.SubElement(author, 'name')
author = ET.SubElement(model, "author")
name = ET.SubElement(author, "name")
name.text = "Generated by blender SDF tools"

xml_string = ET.tostring(model, encoding='unicode')
xml_string = ET.tostring(model, encoding="unicode")
reparsed = minidom.parseString(xml_string)
with open(prefix_path+model_config_filename, "w") as config_file:
with open(path.join(prefix_path, model_config_filename), "w") as config_file:
config_file.write(reparsed.toprettyxml(indent=" "))

#### UI Handling ####
class OT_TestOpenFilebrowser(Operator, ImportHelper):
bl_idname = "test.open_filebrowser"
bl_label = "Save"
directory: bpy.props.StringProperty(name="Outdir Path")

directory: StringProperty(name="Outdir Path")

def execute(self, context):
if not os.path.isdir(self.directory):
print(self.directory + " is not a directory!")
"""Do the export with the selected file."""
if not path.isdir(self.directory):
print(f"{self.directory} is not a directory!")
else:
print("exporting to directory: " + self.directory)
print(f"exporting to directory: {self.directory}")
export_sdf(self.directory)
return {'FINISHED'}
return {"FINISHED"}

def register():
bpy.utils.register_class(OT_TestOpenFilebrowser)
def register():
bpy.utils.register_class(OT_TestOpenFilebrowser)

def unregister():
def unregister():
bpy.utils.unregister_class(OT_TestOpenFilebrowser)

if __name__ == "__main__":
register()
bpy.ops.test.open_filebrowser('INVOKE_DEFAULT')
register()
bpy.ops.test.open_filebrowser("INVOKE_DEFAULT")

# alternatively comment the main code block and do a function call without going through all the ui
# prefix_path = '/home/ddeng/blender_lightmap/final_office/office/'
# export_sdf(prefix_path)

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