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'''OpenGL extension ARB.base_instance
This module customises the behaviour of the
OpenGL.raw.GL.ARB.base_instance to provide a more
Python-friendly API
Overview (from the spec)
This extension allows the offset within buffer objects used for instanced
rendering to be specified. This is congruent with the <first> parameter
in glDrawArrays and the <basevertex> parameter in glDrawElements. When
instanced rendering is performed (for example, through
glDrawArraysInstanced), instanced vertex attributes whose vertex attribute
divisors are non-zero are fetched from enabled vertex arrays per-instance
rather than per-vertex. However, in unextended OpenGL, there is no way to
define the offset into those arrays from which the attributes are fetched.
This extension adds that offset in the form of a <basevertex> parameter
to several new procedures.
The <basevertex> parameter is added to the index of the array element, after
division by the vertex attribute divisor. This allows several sets of
instanced vertex attribute data to be stored in a single vertex array, and
the base offset of that data to be specified for each draw. Further, this
extension exposes the <basevertex> parameter as the final and previously
undefined structure member of the draw-indirect data structure.
The official definition of this extension is available here:
http://www.opengl.org/registry/specs/ARB/base_instance.txt
'''
from OpenGL import platform, constant, arrays
from OpenGL import extensions, wrapper
import ctypes
from OpenGL.raw.GL import _types, _glgets
from OpenGL.raw.GL.ARB.base_instance import *
from OpenGL.raw.GL.ARB.base_instance import _EXTENSION_NAME
def glInitBaseInstanceARB():
'''Return boolean indicating whether this extension is available'''
from OpenGL import extensions
return extensions.hasGLExtension( _EXTENSION_NAME )
# INPUT glDrawElementsInstancedBaseInstance.indices size not checked against count
glDrawElementsInstancedBaseInstance=wrapper.wrapper(glDrawElementsInstancedBaseInstance).setInputArraySize(
'indices', None
)
# INPUT glDrawElementsInstancedBaseVertexBaseInstance.indices size not checked against count
glDrawElementsInstancedBaseVertexBaseInstance=wrapper.wrapper(glDrawElementsInstancedBaseVertexBaseInstance).setInputArraySize(
'indices', None
)
### END AUTOGENERATED SECTION
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