| '''OpenGL extension NV.parameter_buffer_object2 |
| |
| This module customises the behaviour of the |
| OpenGL.raw.GL.NV.parameter_buffer_object2 to provide a more |
| Python-friendly API |
| |
| 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: |
| http://www.opengl.org/registry/specs/NV/parameter_buffer_object2.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.NV.parameter_buffer_object2 import * |
| from OpenGL.raw.GL.NV.parameter_buffer_object2 import _EXTENSION_NAME |
|
|
| def glInitParameterBufferObject2NV(): |
| '''Return boolean indicating whether this extension is available''' |
| from OpenGL import extensions |
| return extensions.hasGLExtension( _EXTENSION_NAME ) |
|
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| |
