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'''OpenGL extension EXT.framebuffer_object
This module customises the behaviour of the
OpenGL.raw.GL.EXT.framebuffer_object to provide a more
Python-friendly API
Overview (from the spec)
This extension defines a simple interface for drawing to rendering
destinations other than the buffers provided to the GL by the
window-system.
In this extension, these newly defined rendering destinations are
known collectively as "framebuffer-attachable images". This
extension provides a mechanism for attaching framebuffer-attachable
images to the GL framebuffer as one of the standard GL logical
buffers: color, depth, and stencil. (Attaching a
framebuffer-attachable image to the accum logical buffer is left for
a future extension to define). When a framebuffer-attachable image
is attached to the framebuffer, it is used as the source and
destination of fragment operations as described in Chapter 4.
By allowing the use of a framebuffer-attachable image as a rendering
destination, this extension enables a form of "offscreen" rendering.
Furthermore, "render to texture" is supported by allowing the images
of a texture to be used as framebuffer-attachable images. A
particular image of a texture object is selected for use as a
framebuffer-attachable image by specifying the mipmap level, cube
map face (for a cube map texture), and z-offset (for a 3D texture)
that identifies the image. The "render to texture" semantics of
this extension are similar to performing traditional rendering to
the framebuffer, followed immediately by a call to CopyTexSubImage.
However, by using this extension instead, an application can achieve
the same effect, but with the advantage that the GL can usually
eliminate the data copy that would have been incurred by calling
CopyTexSubImage.
This extension also defines a new GL object type, called a
"renderbuffer", which encapsulates a single 2D pixel image. The
image of renderbuffer can be used as a framebuffer-attachable image
for generalized offscreen rendering and it also provides a means to
support rendering to GL logical buffer types which have no
corresponding texture format (stencil, accum, etc). A renderbuffer
is similar to a texture in that both renderbuffers and textures can
be independently allocated and shared among multiple contexts. The
framework defined by this extension is general enough that support
for attaching images from GL objects other than textures and
renderbuffers could be added by layered extensions.
To facilitate efficient switching between collections of
framebuffer-attachable images, this extension introduces another new
GL object, called a framebuffer object. A framebuffer object
contains the state that defines the traditional GL framebuffer,
including its set of images. Prior to this extension, it was the
window-system which defined and managed this collection of images,
traditionally by grouping them into a "drawable". The window-system
API's would also provide a function (i.e., wglMakeCurrent,
glXMakeCurrent, aglSetDrawable, etc.) to bind a drawable with a GL
context (as is done in the WGL_ARB_pbuffer extension). In this
extension however, this functionality is subsumed by the GL and the
GL provides the function BindFramebufferEXT to bind a framebuffer
object to the current context. Later, the context can bind back to
the window-system-provided framebuffer in order to display rendered
content.
Previous extensions that enabled rendering to a texture have been
much more complicated. One example is the combination of
ARB_pbuffer and ARB_render_texture, both of which are window-system
extensions. This combination requires calling MakeCurrent, an
operation that may be expensive, to switch between the window and
the pbuffer drawables. An application must create one pbuffer per
renderable texture in order to portably use ARB_render_texture. An
application must maintain at least one GL context per texture
format, because each context can only operate on a single
pixelformat or FBConfig. All of these characteristics make
ARB_render_texture both inefficient and cumbersome to use.
EXT_framebuffer_object, on the other hand, is both simpler to use
and more efficient than ARB_render_texture. The
EXT_framebuffer_object API is contained wholly within the GL API and
has no (non-portable) window-system components. Under
EXT_framebuffer_object, it is not necessary to create a second GL
context when rendering to a texture image whose format differs from
that of the window. Finally, unlike the pbuffers of
ARB_render_texture, a single framebuffer object can facilitate
rendering to an unlimited number of texture objects.
The official definition of this extension is available here:
http://www.opengl.org/registry/specs/EXT/framebuffer_object.txt
'''
from OpenGL import platform, constants, constant, arrays
from OpenGL import extensions, wrapper
from OpenGL.GL import glget
import ctypes
from OpenGL.raw.GL.EXT.framebuffer_object import *
### END AUTOGENERATED SECTION
from OpenGL.lazywrapper import lazy
glGenFramebuffersEXT = wrapper.wrapper(glGenFramebuffersEXT).setOutput(
'framebuffers',
lambda x: (x,),
'n')
glGenRenderbuffersEXT = wrapper.wrapper(glGenRenderbuffersEXT).setOutput(
'renderbuffers',
lambda x: (x,),
'n')
@lazy( glDeleteFramebuffersEXT )
def glDeleteFramebuffersEXT( baseOperation, n, framebuffers=None ):
"""glDeleteFramebuffersEXT( framebuffers ) -> None
"""
if framebuffers is None:
framebuffers = arrays.GLuintArray.asArray( n )
n = arrays.GLuintArray.arraySize( framebuffers )
return baseOperation( n, framebuffers )
#glBindRenderbufferEXT # doesn't require wrapping
#glBindFramebufferEXT # doesn't require wrapping
#glBindRenderbufferEXT # doesn't require wrapping
#glCheckFramebufferStatusEXT
#glDeleteFramebuffersEXT # should be wrapped to eliminate 'length'
#glDeleteRenderbuffersEXT # should be wrapped to eliminate 'length'
#glFramebufferRenderbufferEXT
#glFramebufferTexture1DEXT
#glFramebufferTexture2DEXT
#glFramebufferTexture3DEXT
#glGenFramebuffersEXT # wrapped
#glGenRenderbuffersEXT # wrapped
#glGenerateMipmapEXT
#glGetFramebufferAttachmentParameterivEXT
#glGetRenderbufferParameterivEXT
#glInitFramebufferObjectEXT
#glIsFramebufferEXT
#glIsRenderbufferEXT
#glRenderbufferStorageEXT # doesn't require wrapping
#glget.addGLGetConstant( GL_MAX_COLOR_ATTACHMENTS_EXT, (1,))
#glget.addGLGetConstant( GL_FRAMEBUFFER_BINDING_EXT, (1,))
#glget.addGLGetConstant( GL_RENDERBUFFER_BINDING_EXT, (1,))
#glget.addGLGetConstant( GL_MAX_RENDERBUFFER_SIZE_EXT, (1,))
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