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# -*- coding: utf-8 -*-
# vispy: testskip
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
"""A ctypes-based API to OSMesa
"""
from __future__ import print_function
import os
import ctypes
import ctypes.util
from ctypes import c_int as _c_int, c_uint as _c_uint, c_void_p
# See vispy/gloo/gl/_constants.py for reference
GL_RGBA = 6408
GL_UNSIGNED_BYTE = 5121
GL_VERSION = 7938
_osmesa_file = None
if 'OSMESA_LIBRARY' in os.environ:
if os.path.exists(os.environ['OSMESA_LIBRARY']):
_osmesa_file = os.path.realpath(os.environ['OSMESA_LIBRARY'])
# Else, try to find it
if _osmesa_file is None:
_osmesa_file = ctypes.util.find_library('OSMesa')
# Else, we failed and exit
if _osmesa_file is None:
raise OSError('OSMesa library not found')
# Load it
_lib = ctypes.CDLL(_osmesa_file)
# Constants
OSMESA_RGBA = GL_RGBA
# Functions
# GLAPI OSMesaContext GLAPIENTRY
# OSMesaCreateContext( GLenum format, OSMesaContext sharelist );
_lib.OSMesaCreateContext.argtypes = _c_int, c_void_p
_lib.OSMesaCreateContext.restype = c_void_p
# GLAPI void GLAPIENTRY
# OSMesaDestroyContext( OSMesaContext ctx );
_lib.OSMesaDestroyContext.argtypes = c_void_p,
# GLAPI GLboolean GLAPIENTRY
# OSMesaMakeCurrent( OSMesaContext ctx, void *buffer, GLenum type,
# GLsizei width, GLsizei height );
_lib.OSMesaMakeCurrent.argtypes = c_void_p, c_void_p, _c_int, _c_int, _c_int
_lib.OSMesaMakeCurrent.restype = _c_int
# GLAPI OSMesaContext GLAPIENTRY
# OSMesaGetCurrentContext( void );
_lib.OSMesaGetCurrentContext.restype = c_void_p
def allocate_pixels_buffer(width, height):
"""Helper function to allocate a buffer to contain an image of
width * height suitable for OSMesaMakeCurrent"""
# Seems like OSMesa has some trouble with non-RGBA buffers, so enforce
# RGBA
return (_c_uint * width * height * 4)()
def OSMesaCreateContext():
return ctypes.cast(_lib.OSMesaCreateContext(OSMESA_RGBA, None), c_void_p)
def OSMesaDestroyContext(context):
_lib.OSMesaDestroyContext(context)
def OSMesaMakeCurrent(context, buffer, width, height):
ret = _lib.OSMesaMakeCurrent(context, buffer, GL_UNSIGNED_BYTE,
width, height)
return ret != 0
def OSMesaGetCurrentContext():
return c_void_p(_lib.OSMesaGetCurrentContext())
if __name__ == '__main__':
"""This test basic OSMesa functionality"""
# If you have OSMesa installed alongside normal OpenGL, execute with
# VISPY_GL_LIB=/opt/osmesa_llvmpipe/lib/libGLESv2.so \
# LD_LIBRARY_PATH=/opt/osmesa_llvmpipe/lib/ \
# OSMESA_LIBRARY=/opt/osmesa_llvmpipe/lib/libOSMesa.so \
# python vispy/ext/osmesa.py
context = OSMesaCreateContext()
w, h = 640, 480
pixels = allocate_pixels_buffer(w, h)
ok = OSMesaMakeCurrent(context, pixels, 640, 480)
if not ok:
raise RuntimeError('Failed OSMesaMakeCurrent')
if not (OSMesaGetCurrentContext().value == context.value):
raise RuntimeError('OSMesa context not correctly attached')
_lib.glGetString.argtypes = (ctypes.c_uint,)
_lib.glGetString.restype = ctypes.c_char_p
print("OpenGL version : ", _lib.glGetString(GL_VERSION))
OSMesaDestroyContext(context)
if OSMesaGetCurrentContext().value is not None:
raise RuntimeError('Failed to destroy OSMesa context')
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