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# Source code for silx.gui._glutils.FramebufferTexture

    # /*##########################################################################
    #
    # Copyright (c) 2014-2020 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.
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    # ###########################################################################*/
    """Association of a texture and a framebuffer object for off-screen rendering.
    """

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

    import logging

    from . import gl
    from .Texture import Texture

    _logger = logging.getLogger(__name__)

    class FramebufferTexture(object):
        """Framebuffer with a texture.

        Aimed at off-screen rendering to texture.

        :param internalFormat: OpenGL texture internal format
        :param shape: Shape (height, width) of the framebuffer and texture
        :type shape: 2-tuple of int
        :param stencilFormat: Stencil renderbuffer format
        :param depthFormat: Depth renderbuffer format
        :param kwargs: Extra arguments for :class:`Texture` constructor
        """

        _PACKED_FORMAT = gl.GL_DEPTH24_STENCIL8, gl.GL_DEPTH_STENCIL

        def __init__(
            self,
            internalFormat,
            shape,
            stencilFormat=gl.GL_DEPTH24_STENCIL8,
            depthFormat=gl.GL_DEPTH24_STENCIL8,
            **kwargs,
        ):
            self._texture = Texture(internalFormat, shape=shape, **kwargs)
            self._texture.prepare()

            self._previousFramebuffer = 0  # Used by with statement

            self._name = gl.glGenFramebuffers(1)

            with self:  # Bind FBO
                # Attachments
                gl.glFramebufferTexture2D(
                    gl.GL_FRAMEBUFFER,
                    gl.GL_COLOR_ATTACHMENT0,
                    gl.GL_TEXTURE_2D,
                    self._texture.name,
                    0,
                )

                height, width = self._texture.shape

                if stencilFormat is not None:
                    self._stencilId = gl.glGenRenderbuffers(1)
                    gl.glBindRenderbuffer(gl.GL_RENDERBUFFER, self._stencilId)
                    gl.glRenderbufferStorage(
                        gl.GL_RENDERBUFFER, stencilFormat, width, height
                    )
                    gl.glFramebufferRenderbuffer(
                        gl.GL_FRAMEBUFFER,
                        gl.GL_STENCIL_ATTACHMENT,
                        gl.GL_RENDERBUFFER,
                        self._stencilId,
                    )
                else:
                    self._stencilId = None

                if depthFormat is not None:
                    if self._stencilId and depthFormat in self._PACKED_FORMAT:
                        self._depthId = self._stencilId
                    else:
                        self._depthId = gl.glGenRenderbuffers(1)
                        gl.glBindRenderbuffer(gl.GL_RENDERBUFFER, self._depthId)
                        gl.glRenderbufferStorage(
                            gl.GL_RENDERBUFFER, depthFormat, width, height
                        )
                    gl.glFramebufferRenderbuffer(
                        gl.GL_FRAMEBUFFER,
                        gl.GL_DEPTH_ATTACHMENT,
                        gl.GL_RENDERBUFFER,
                        self._depthId,
                    )
                else:
                    self._depthId = None

                status = gl.glCheckFramebufferStatus(gl.GL_FRAMEBUFFER)
                if status != gl.GL_FRAMEBUFFER_COMPLETE:
                    _logger.error(
                        "OpenGL framebuffer initialization not complete, display may fail (error %d)",
                        status,
                    )

        @property
        def shape(self):
            """Shape of the framebuffer (height, width)"""
            return self._texture.shape

        @property
        def texture(self):
            """The texture this framebuffer is rendering to.

            The life-cycle of the texture is managed by this object"""
            return self._texture

        @property
        def name(self):
            """OpenGL name of the framebuffer"""
            if self._name is not None:
                return self._name
            else:
                raise RuntimeError(
                    "No OpenGL framebuffer resource, \
                                   discard has already been called"
                )

        def bind(self):
            """Bind this framebuffer for rendering"""
            gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, self.name)

        # with statement

        def __enter__(self):
            self._previousFramebuffer = gl.glGetInteger(gl.GL_FRAMEBUFFER_BINDING)
            self.bind()

        def __exit__(self, exctype, excvalue, traceback):
            gl.glBindFramebuffer(gl.GL_FRAMEBUFFER, self._previousFramebuffer)
            self._previousFramebuffer = None

        def discard(self):
            """Delete associated OpenGL resources including texture"""
            if self._name is not None:
                gl.glDeleteFramebuffers(self._name)
                self._name = None

                if self._stencilId is not None:
                    gl.glDeleteRenderbuffers(self._stencilId)
                    if self._stencilId == self._depthId:
                        self._depthId = None
                    self._stencilId = None
                if self._depthId is not None:
                    gl.glDeleteRenderbuffers(self._depthId)
                    self._depthId = None

                self._texture.discard()  # Also discard the texture
            else:
                _logger.warning("Discard has already been called")