OpenGL extension NV.parameter_buffer_object2
This module customises the behaviour of the
OpenGL.raw.GL.NV.parameter_buffer_object2 to provide a more
Overview (from the spec)
This extension builds on the NV_parameter_buffer_object extension to
provide additional flexibility in sourcing data from buffer objects.
The original NV_parameter_buffer_object (PaBO) extension provided the
ability to bind buffer objects to a set of numbered binding points and
access them in assembly programs as though they were arrays of 32-bit
scalars (via the BUFFER variable type) or arrays of four-component vectors
with 32-bit scalar components (via the BUFFER4 variable type). However,
the functionality it provided had some significant limits on flexibility.
Since any given buffer binding point could be used either as a BUFFER or
BUFFER4, but not both, programs couldn't do both 32- and 128-bit fetches
from a single binding point. Additionally, No support was provided for
8-, 16-, or 64-bit fetches, though they could be emulated using a larger
loads, with bitfield operations and/or write masking to put components in
the right places. Indexing was supported, but strides were limited to 4-
and 16-byte multiples, depending on whether BUFFER or BUFFER4 is used.
This new extension provides the buffer variable declaration type CBUFFER
to specify a buffer that is treated as an array of bytes, rather than an
array of words or vectors. The LDC instruction allows programs to extract
a vector of data from a CBUFFER variable, using a size and component count
specified in the opcode modifier. 1-, 2-, and 4-component fetches are
supported. The LDC instruction supports byte offsets using normal array
indexing mechanisms; both run-time and immediate offsets are supported.
Offsets used for a buffer object fetch are required to be aligned to the
size of the fetch (1, 2, 4, 8, or 16 bytes).
The official definition of this extension is available here:
|EXTENSION_NAME = 'GL_NV_parameter_buffer_object2'|
__file__ = '/home/mcfletch/pylive/OpenGL/GL/NV/parameter_buffer_object2.pyc'
__name__ = 'OpenGL.GL.NV.parameter_buffer_object2'
__package__ = 'OpenGL.GL.NV'