cleanup:

+ hardcoded constants
+ comments and docs

blender_generate_image_and_depth.py

 '''
 Copyright (C) 2020, Elphel Inc.
 SPDX-License-Identifier: GPL-3.0-or-later
-Author: Oleg K Dzhimiev <oleg@elphel.com> 
+Author: Oleg K Dzhimiev <oleg@elphel.com>
+'''
 
+'''
 Usage:
 
 ~$ blender -b -P blender_generate_image_and_depth.py -- file1,file2,..,fileN
 or
 ~$ <path-to-blender>/blender -b -P blender_generate_image_and_depth.py -- file1,file2,..,fileN
 
-  - file names must include path
-  - must be .obj format
-  - at the same path all accompanying files must be present - .mtl and textures
-  - no space after commas
+Notes:
+  - *.obj format
+  - include path in the *.obj name
+  - unique *.obj names - everything is dumped into a single folder
+  - .mtl and textures, if exist, must be in the *.obj path
+  - no spaces after commas in the file list
   - blender executable must be in the path
     - ~$ which blender
     - alternatively can call from blender path
 
 Example:
 
-~$ blender -b -P blender_generate_image_and_depth.py -- input/1527256815_550165_v01/1527256815_550165.obj,input/1527256858_750165_v01/1527256858_750165.obj
+~$ blender -b -P blender_generate_image_and_depth.py -- path1/model1.obj,path2/model2.obj
 
 Output:
 
@@ -32,21 +36,28 @@ Comment:
   - didn't work for some models in Blender v2.82.7
 
 '''
-
 import numpy as np
 import os
 import sys
 
 import bpy
 
+# hardcoded constants
+img_w = 2592
+img_h = 1902
+img_fov_degs = 66.8
+
+model_default_rotation = (90*np.pi/180.0, 0, 0)
 model_output_folder = "output"
+# end constants
 
 scene = bpy.context.scene
 world = scene.world
 camera = scene.camera
 
-scene.render.resolution_x = 2592
-scene.render.resolution_y = 1902
+# fixed resolution for now
+scene.render.resolution_x = img_w
+scene.render.resolution_y = img_h
 scene.render.resolution_percentage = 100
 
 world.use_nodes = False
@@ -58,10 +69,10 @@ objs.remove(objs["Light"], do_unlink=True)
 
 camera.location = (0,0,0)
 camera.rotation_mode = "XYZ"
-camera.rotation_euler = (90*np.pi/180.0, 0, 0)
+camera.rotation_euler = model_default_rotation
 camera.data.clip_end = 10000
 camera.data.clip_start = 0.1
-camera.data.angle = 66.8*np.pi/180
+camera.data.angle = img_fov_degs*np.pi/180
 
 bpy.context.scene.use_nodes = True
 
@@ -69,6 +80,7 @@ rn = scene.node_tree.nodes.new('CompositorNodeRLayers')
 depth = scene.node_tree.nodes.new('CompositorNodeOutputFile')
 depth.format.file_format = 'OPEN_EXR'
 depth.format.color_depth = '32'
+# TODO: try BW
 depth.format.color_mode = 'RGB'
 depth.format.exr_codec = 'ZIP'
 depth.base_path = model_output_folder
@@ -78,21 +90,12 @@ scene.node_tree.links.new(rn.outputs[2], depth.inputs[0])
 
 fpaths = sys.argv[-1].split(',')
 
-TEST=False
-if (TEST):
-    fpaths = ['input/1527256815_550165_v01/1527256815_550165.obj',
-              'input/1527256903_350165/v03/1527256903_350165.obj',
-              'input/1488240695_710844_x3d105/1488240695_710844.obj']
-
-print(fpaths)
-
 if(not (os.path.isdir(model_output_folder))):
     os.mkdir(model_output_folder)
 
 for fpath in fpaths:
 
     obj_name = fpath.split('/')[-1][:-4]
-    print(obj_name)
 
     bpy.ops.import_scene.obj(filepath=fpath, use_smooth_groups=False)