"""Headless GPU-accelerated OpenGL context creation on Google Colaboratory. Typical usage: # Optional PyOpenGL configuratiopn can be done here. # import OpenGL # OpenGL.ERROR_CHECKING = True # 'glcontext' must be imported before any OpenGL.* API. from lucid.misc.gl.glcontext import create_opengl_context # Now it's safe to import OpenGL and EGL functions import OpenGL.GL as gl # create_opengl_context() creates a GL context that is attached to an # offscreen surface of the specified size. Note that rendering to buffers # of other sizes and formats is still possible with OpenGL Framebuffers. # # Users are expected to directly use the EGL API in case more advanced # context management is required. width, height = 640, 480 create_opengl_context((width, height)) # OpenGL context is available here. """ from __future__ import print_function # pylint: disable=unused-import,g-import-not-at-top,g-statement-before-imports try: import OpenGL except: print('This module depends on PyOpenGL.') print('Please run "\033[1m!pip install -q pyopengl\033[0m" ' 'prior importing this module.') raise import ctypes from ctypes import pointer, util import os os.environ['PYOPENGL_PLATFORM'] = 'egl' # OpenGL loading workaround. # # * PyOpenGL tries to load libGL, but we need libOpenGL, see [1,2]. # This could have been solved by a symlink libGL->libOpenGL, but: # # * Python 2.7 can't find libGL and linEGL due to a bug (see [3]) # in ctypes.util, that was only wixed in Python 3.6. # # So, the only solution I've found is to monkeypatch ctypes.util # [1] https://devblogs.nvidia.com/egl-eye-opengl-visualization-without-x-server/ # [2] https://devblogs.nvidia.com/linking-opengl-server-side-rendering/ # [3] https://bugs.python.org/issue9998 _find_library_old = ctypes.util.find_library try: def _find_library_new(name): return { 'GL': 'libOpenGL.so', 'EGL': 'libEGL.so', }.get(name, _find_library_old(name)) util.find_library = _find_library_new import OpenGL.GL as gl import OpenGL.EGL as egl from OpenGL import error from OpenGL.EGL.EXT.device_base import egl_get_devices from OpenGL.raw.EGL.EXT.platform_device import EGL_PLATFORM_DEVICE_EXT except: print('Unable to load OpenGL libraries. ' 'Make sure you use GPU-enabled backend.') print('Press "Runtime->Change runtime type" and set ' '"Hardware accelerator" to GPU.') raise finally: util.find_library = _find_library_old def create_initialized_headless_egl_display(): """Creates an initialized EGL display directly on a device.""" for device in egl_get_devices(): display = egl.eglGetPlatformDisplayEXT(EGL_PLATFORM_DEVICE_EXT, device, None) if display != egl.EGL_NO_DISPLAY and egl.eglGetError() == egl.EGL_SUCCESS: # `eglInitialize` may or may not raise an exception on failure depending # on how PyOpenGL is configured. We therefore catch a `GLError` and also # manually check the output of `eglGetError()` here. try: initialized = egl.eglInitialize(display, None, None) except error.GLError: pass else: if initialized == egl.EGL_TRUE and egl.eglGetError() == egl.EGL_SUCCESS: return display return egl.EGL_NO_DISPLAY def create_opengl_context(surface_size=(640, 480)): """Create offscreen OpenGL context and make it current. Users are expected to directly use EGL API in case more advanced context management is required. Args: surface_size: (width, height), size of the offscreen rendering surface. """ egl_display = create_initialized_headless_egl_display() if egl_display == egl.EGL_NO_DISPLAY: raise ImportError('Cannot initialize a headless EGL display.') major, minor = egl.EGLint(), egl.EGLint() egl.eglInitialize(egl_display, pointer(major), pointer(minor)) config_attribs = [ egl.EGL_SURFACE_TYPE, egl.EGL_PBUFFER_BIT, egl.EGL_BLUE_SIZE, 8, egl.EGL_GREEN_SIZE, 8, egl.EGL_RED_SIZE, 8, egl.EGL_DEPTH_SIZE, 24, egl.EGL_RENDERABLE_TYPE, egl.EGL_OPENGL_BIT, egl.EGL_NONE ] config_attribs = (egl.EGLint * len(config_attribs))(*config_attribs) num_configs = egl.EGLint() egl_cfg = egl.EGLConfig() egl.eglChooseConfig(egl_display, config_attribs, pointer(egl_cfg), 1, pointer(num_configs)) width, height = surface_size pbuffer_attribs = [ egl.EGL_WIDTH, width, egl.EGL_HEIGHT, height, egl.EGL_NONE, ] pbuffer_attribs = (egl.EGLint * len(pbuffer_attribs))(*pbuffer_attribs) egl_surf = egl.eglCreatePbufferSurface(egl_display, egl_cfg, pbuffer_attribs) egl.eglBindAPI(egl.EGL_OPENGL_API) egl_context = egl.eglCreateContext(egl_display, egl_cfg, egl.EGL_NO_CONTEXT, None) egl.eglMakeCurrent(egl_display, egl_surf, egl_surf, egl_context)