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'''OpenGL extension EXT.shader_framebuffer_fetch
This module customises the behaviour of the
OpenGL.raw.GLES2.EXT.shader_framebuffer_fetch to provide a more
Python-friendly API
Overview (from the spec)
Conventional OpenGL blending provides a configurable series of operations
that can be used to combine the output values from a fragment shader with
the values already in the framebuffer. While these operations are
suitable for basic image compositing, other compositing operations or
operations that treat fragment output as something other than a color
(normals, for instance) may not be expressible without multiple passes or
render-to-texture operations.
This extension provides a mechanism whereby a fragment shader may read
existing framebuffer data as input. This can be used to implement
compositing operations that would have been inconvenient or impossible with
fixed-function blending. It can also be used to apply a function to the
framebuffer color, by writing a shader which uses the existing framebuffer
color as its only input.
This extension provides two alternative name strings:
- GL_EXT_shader_framebuffer_fetch guarantees full coherency between
framebuffer reads and writes. If this extension string is exposed, the
result of reading from the framebuffer from a fragment shader invocation
is guaranteed to reflect values written by any previous overlapping
samples in API primitive order, unless requested otherwise in the shader
source using the noncoherent layout qualifier.
- GL_EXT_shader_framebuffer_fetch_non_coherent provides limited implicit
coherency guarantees. Instead, the application is expected to call the
FramebufferFetchBarrierEXT command for previous framebuffer writes to
become visible to subsequent fragment shader invocations. For this
extension to give well-defined results applications may have to split
rendering into multiple passes separated with FramebufferFetchBarrierEXT
calls. The functionality provided by this extension is requested in the
shader source using the noncoherent layout qualifier.
The official definition of this extension is available here:
http://www.opengl.org/registry/specs/EXT/shader_framebuffer_fetch.txt
'''
from OpenGL import platform, constant, arrays
from OpenGL import extensions, wrapper
import ctypes
from OpenGL.raw.GLES2 import _types, _glgets
from OpenGL.raw.GLES2.EXT.shader_framebuffer_fetch import *
from OpenGL.raw.GLES2.EXT.shader_framebuffer_fetch import _EXTENSION_NAME
def glInitShaderFramebufferFetchEXT():
'''Return boolean indicating whether this extension is available'''
from OpenGL import extensions
return extensions.hasGLExtension( _EXTENSION_NAME )
### END AUTOGENERATED SECTION
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