bcgcmd.py

# TODO
#  commands like preview-lopoly, preview-hipoly, preview-full...

import argparse
import distutils.spawn
import sys,os,stat
import json

def fatal(msg):
	sys.stderr.write(msg + "\n")
	sys.exit(1)

def get_blender_path():
	def is_executable(path):
		if not path: return False
		m = os.stat(path)[stat.ST_MODE]
		return not stat.S_ISDIR(m) and bool((m&stat.S_IXUSR) or (m&stat.S_IXGRP) or (m&stat.S_IXOTH))

	path = os.getenv("BCG_BLENDER")
	if is_executable(path): return path

	path = distutils.spawn.find_executable("blender")
	if is_executable(path): return path

	if sys.platform == "darwin":
		# look for blender in standard MacOS location
		for app in ["blender.app", "Blender.app"]:
			path = "/Applications/%s/Contents/MacOS/blender" % app
			if is_executable(path): return path

	fatal("blender not found (search order: BCG_BLENDER environment variable, then 'blender' in $PATH, then platform specific stuff)")


def run_blender(bcgscript, background, args):
	blender_path = get_blender_path()

	argv = [blender_path, "-noaudio"]
	if background: argv += ["-b"]
	argv += ["-P", bcgscript]
	env = {}

	env["BCG_DIR"] = os.path.dirname(os.path.realpath(__file__))
	for k,v in os.environ.items():
		env[k] = v
	env["BCG_ARGS"] = json.dumps(args)

	# TODO pass options in an environment variable? json encoded or
	# something?
	os.execve(blender_path, argv, env)

parser = argparse.ArgumentParser(prog='bcg')
subparsers = parser.add_subparsers(dest='cmd', help='sub-command help')

# bcg preview
parser_preview = subparsers.add_parser('preview', help='show scene in blender')
parser_preview.add_argument('bcgscript', metavar='<bcg script>')

# bcg build
parser_build = subparsers.add_parser('build', help='build scene')
parser_build.add_argument('bcgscript', metavar='<bcg script>')

args = parser.parse_args()


do_execute = False
background = False
pass_args = {}

if args.cmd is None:
	parser.print_help(sys.stderr)
	sys.exit(1)
elif args.cmd == "preview":
	do_execute = True
	background = False
	pass_args['preview'] = True
elif args.cmd == "build":
	do_execute = True
	background = True
else:
	raise RuntimeError("unhandled cmd: %s" % cmd)

if do_execute: run_blender(args.bcgscript, background = background, args = pass_args)