# Copyright 2017-2018 The dm_control Authors.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

# ============================================================================

"""OpenGL context management for rendering MuJoCo scenes.

By default, the `Renderer` class will try to load one of the following rendering

APIs, in descending order of priority: GLFW > EGL > OSMesa.

It is also possible to select a specific backend by setting the `MUJOCO_GL=`

environment variable to 'glfw', 'egl', or 'osmesa'.

"""

import collections

import os

from absl import logging

from dm_control._render import constants

BACKEND = os.environ.get(constants.MUJOCO_GL)

# pylint: disable=g-import-not-at-top

def _import_egl():

from dm_control._render.pyopengl.egl_renderer import EGLContext

return EGLContext

def _import_glfw():

from dm_control._render.glfw_renderer import GLFWContext

return GLFWContext

def _import_osmesa():

from dm_control._render.pyopengl.osmesa_renderer import OSMesaContext

return OSMesaContext

# Import removed.

# pylint: enable=g-import-not-at-top

def _no_renderer():

def no_renderer(*args, **kwargs):

del args, kwargs

raise RuntimeError('No OpenGL rendering backend is available.')

return no_renderer

_ALL_RENDERERS = (

(constants.GLFW, _import_glfw),

(constants.EGL, _import_egl),

(constants.OSMESA, _import_osmesa),

# Option removed.

)

_NO_RENDERER = (

(constants.NO_RENDERER, _no_renderer),

)

if BACKEND is not None:

# If a backend was specified, try importing it and error if unsuccessful.

import_func = None

for names, importer in _ALL_RENDERERS + _NO_RENDERER:

if BACKEND in names:

import_func = importer

BACKEND = names[0] # canonicalize the renderer name

break

if import_func is None:

all_names = set()

for names, _ in _ALL_RENDERERS + _NO_RENDERER:

all_names.update(names)

raise RuntimeError(

'Environment variable {} must be one of {!r}: got {!r}.'

.format(constants.MUJOCO_GL, sorted(all_names), BACKEND))

logging.info('MUJOCO_GL=%s, attempting to import specified OpenGL backend.',

BACKEND)

Renderer = import_func()

else:

logging.info('MUJOCO_GL is not set, so an OpenGL backend will be chosen '

'automatically.')

# Otherwise try importing them in descending order of priority until

# successful.

for names, import_func in _ALL_RENDERERS:

try:

Renderer = import_func()

BACKEND = names[0]

logging.info('Successfully imported OpenGL backend: %s', names[0])

break

except ImportError:

logging.info('Failed to import OpenGL backend: %s', names[0])

if BACKEND is None:

logging.info('No OpenGL backend could be imported. Attempting to create a '

'rendering context will result in a RuntimeError.')

Renderer = _no_renderer()

USING_GPU = BACKEND in constants.EGL + constants.GLFW