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'''OpenGL extension EXT.geometry_shader
This module customises the behaviour of the
OpenGL.raw.GLES2.EXT.geometry_shader to provide a more
Python-friendly API
Overview (from the spec)
EXT_geometry_shader defines a new shader type available to be run on the
GPU, called a geometry shader. Geometry shaders are run after vertices are
transformed, but prior to color clamping, flatshading and clipping.
A geometry shader begins with a single primitive (point, line,
triangle). It can read the attributes of any of the vertices in the
primitive and use them to generate new primitives. A geometry shader has a
fixed output primitive type (point, line strip, or triangle strip) and
emits vertices to define a new primitive. A geometry shader can emit
multiple disconnected primitives. The primitives emitted by the geometry
shader are clipped and then processed like an equivalent primitive
specified by the application.
Furthermore, EXT_geometry_shader provides four additional primitive
types: lines with adjacency, line strips with adjacency, separate
triangles with adjacency, and triangle strips with adjacency. Some of the
vertices specified in these new primitive types are not part of the
ordinary primitives, instead they represent neighboring vertices that are
adjacent to the two line segment end points (lines/strips) or the three
triangle edges (triangles/tstrips). These vertices can be accessed by
geometry shaders and used to match up the vertices emitted by the geometry
shader with those of neighboring primitives.
Since geometry shaders expect a specific input primitive type, an error
will occur if the application presents primitives of a different type.
For example, if a geometry shader expects points, an error will occur at
drawing time if a primitive mode of TRIANGLES is specified.
This extension also adds the notion of layered framebuffer attachments
and framebuffers that can be used in conjunction with geometry shaders
to allow programs to direct primitives to a face of a cube map or layer
of a three-dimensional texture or two-dimensional array texture. The
layer used for rendering can be selected by the geometry shader at run
time. The framebuffer layer count present in GL 4.x and removed from
ES 3.1 is restored.
Not all geometry shader implementations have the ability to write the
point size from a geometry shader. Thus a second extension string and
shading language enable are provided for implementations which do
support geometry shader point size.
This extension relies on the EXT_shader_io_blocks extension to provide
the required functionality for declaring input and output blocks and
interfacing between shaders.
The official definition of this extension is available here:
http://www.opengl.org/registry/specs/EXT/geometry_shader.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.geometry_shader import *
from OpenGL.raw.GLES2.EXT.geometry_shader import _EXTENSION_NAME
def glInitGeometryShaderEXT():
'''Return boolean indicating whether this extension is available'''
from OpenGL import extensions
return extensions.hasGLExtension( _EXTENSION_NAME )
### END AUTOGENERATED SECTION
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