Skip to main content
`Ctrl`+`K`

# Source code for silx.gui._glutils.gl

    # /*##########################################################################
    #
    # Copyright (c) 2014-2022 European Synchrotron Radiation Facility
    #
    # Permission is hereby granted, free of charge, to any person obtaining a copy
    # of this software and associated documentation files (the "Software"), to deal
    # in the Software without restriction, including without limitation the rights
    # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    # copies of the Software, and to permit persons to whom the Software is
    # furnished to do so, subject to the following conditions:
    #
    # The above copyright notice and this permission notice shall be included in
    # all copies or substantial portions of the Software.
    #
    # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    # THE SOFTWARE.
    #
    # ###########################################################################*/
    """This module loads PyOpenGL and provides a namespace for OpenGL."""

    __authors__ = ["T. Vincent"]
    __license__ = "MIT"
    __date__ = "25/07/2016"

    from contextlib import contextmanager as _contextmanager
    from ctypes import c_uint
    import logging
    import sys
    from typing import Optional

    from packaging.version import Version

    _logger = logging.getLogger(__name__)

    import OpenGL

    # Set the following to true for debugging
    if _logger.getEffectiveLevel() <= logging.DEBUG:
        _logger.debug("Enabling PyOpenGL debug flags")
        OpenGL.ERROR_LOGGING = True
        OpenGL.ERROR_CHECKING = True
        OpenGL.ERROR_ON_COPY = True
    else:
        OpenGL.ERROR_LOGGING = False
        OpenGL.ERROR_CHECKING = False
        OpenGL.ERROR_ON_COPY = False

    if sys.version_info >= (3, 12) and Version(OpenGL.__version__) <= Version("3.1.7"):
        # Python3.12 patch: see https://github.com/mcfletch/pyopengl/pull/100
        OpenGL.FormatHandler.by_name("ctypesparameter").check.append("_ctypes.CArgObject")

    import OpenGL.GL as _GL
    from OpenGL.GL import *  # noqa
    import OpenGL.platform

    # Extentions core in OpenGL 3
    from OpenGL.GL.ARB import framebuffer_object as _FBO
    from OpenGL.GL.ARB.framebuffer_object import *  # noqa
    from OpenGL.GL.ARB.texture_rg import GL_R32F, GL_R16F  # noqa
    from OpenGL.GL.ARB.texture_rg import GL_R16, GL_R8  # noqa

    # PyOpenGL 3.0.1 does not define it
    try:
        GLchar
    except NameError:
        from ctypes import c_char

        GLchar = c_char

    def getPlatform() -> Optional[str]:
        """Returns the name of the PyOpenGL class handling the platform.

        E.g., GLXPlatform, EGLPlatform
        """
        try:
            platform = OpenGL.platform.PLATFORM
        except AttributeError:
            return None
        return platform.__class__.__name__

    def getVersion() -> tuple:
        """Returns the GL version as tuple of integers.

        Raises:
            ValueError: If the version returned by the driver is not supported
        """
        try:
            desc = glGetString(GL_VERSION)
            if isinstance(desc, bytes):
                desc = desc.decode("ascii")
            version = desc.split(" ", 1)[0]
            return tuple([int(i) for i in version.split(".")])
        except Exception as e:
            raise ValueError("GL version not properly formatted") from e

    def testGL() -> bool:
        """Test if required OpenGL version and extensions are available.

        This MUST be run with an active OpenGL context.
        """
        version = getVersion()
        major, minor = version[0], version[1]
        if major < 2 or (major == 2 and minor < 1):
            _logger.error("OpenGL version >=2.1 required, running with %s" % version)
            return False

        if major == 2:
            from OpenGL.GL.ARB.framebuffer_object import glInitFramebufferObjectARB
            from OpenGL.GL.ARB.texture_rg import glInitTextureRgARB

            if not glInitFramebufferObjectARB():
                _logger.error("OpenGL GL_ARB_framebuffer_object extension required!")
                return False

            if not glInitTextureRgARB():
                _logger.error("OpenGL GL_ARB_texture_rg extension required!")
                return False

        return True

    # Additional setup
    if hasattr(glget, "addGLGetConstant"):
        glget.addGLGetConstant(GL_FRAMEBUFFER_BINDING, (1,))

    @_contextmanager
    def enabled(capacity, enable=True):
        """Context manager enabling an OpenGL capacity.

        This is not checking the current state of the capacity.

        :param capacity: The OpenGL capacity enum to enable/disable
        :param bool enable:
            True (default) to enable during context, False to disable
        """
        if bool(enable) == glGetBoolean(capacity):
            # Already in the right state: noop
            yield
        elif enable:
            glEnable(capacity)
            yield
            glDisable(capacity)
        else:
            glDisable(capacity)
            yield
            glEnable(capacity)

    def disabled(capacity, disable=True):
        """Context manager disabling an OpenGL capacity.

        This is not checking the current state of the capacity.

        :param capacity: The OpenGL capacity enum to disable/enable
        :param bool disable:
            True (default) to disable during context, False to enable
        """
        return enabled(capacity, not disable)

    # Additional OpenGL wrapping

    def glGetActiveAttrib(program, index):
        """Wrap PyOpenGL glGetActiveAttrib"""
        bufsize = glGetProgramiv(program, GL_ACTIVE_ATTRIBUTE_MAX_LENGTH)
        length = GLsizei()
        size = GLint()
        type_ = GLenum()
        name = (GLchar * bufsize)()

        _GL.glGetActiveAttrib(program, index, bufsize, length, size, type_, name)
        return name.value, size.value, type_.value

    def glDeleteRenderbuffers(buffers):
        if not hasattr(buffers, "__len__"):  # Support single int argument
            buffers = [buffers]
        length = len(buffers)
        _FBO.glDeleteRenderbuffers(length, (c_uint * length)(*buffers))

    def glDeleteFramebuffers(buffers):
        if not hasattr(buffers, "__len__"):  # Support single int argument
            buffers = [buffers]
        length = len(buffers)
        _FBO.glDeleteFramebuffers(length, (c_uint * length)(*buffers))

    def glDeleteBuffers(buffers):
        if not hasattr(buffers, "__len__"):  # Support single int argument
            buffers = [buffers]
        length = len(buffers)
        _GL.glDeleteBuffers(length, (c_uint * length)(*buffers))

    def glDeleteTextures(textures):
        if not hasattr(textures, "__len__"):  # Support single int argument
            textures = [textures]
        length = len(textures)
        _GL.glDeleteTextures((c_uint * length)(*textures))