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# Copyright (c) 2014-2020 European Synchrotron Radiation Facility
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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__)
[docs]
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"
)
[docs]
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
[docs]
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")
