2003-2004 Silicon Graphics, Inc.
glBufferSubData 3G
glBufferSubData updates a subset of a buffer object's data store.

## C Specification

void `glBufferSubData` GLenum target GLintptr offset GLsizeiptr size const GLvoid * data

## Parameters

target

  Specifies the target buffer object. The symbolic constant must be `GL_ARRAY_BUFFER` or `GL_ELEMENT_ARRAY_BUFFER`.

offset

  Specifies the offset into the buffer object's data store where data replacement will begin, measured in bytes.

size

  Specifies the size in bytes of the data store region being replaced.

data

  Specifies a pointer to the new data that will be copied into the data store.

## Description

`glBufferSubData` redefines some or all of the data store for the buffer object currently bound to target. Data starting at byte offset offset and extending for size bytes is copied to the data store from the memory pointed to by data. An error is thrown if offset and size together define a range beyond the bounds of the buffer object's data store.

## Notes

When replacing the entire data store, consider using `glBufferSubData` rather than completely recreating the data store with `glBufferData`. This avoids the cost of reallocating the data store.

Consider using multiple buffer objects to avoid stalling the rendering pipeline during data store updates. If any rendering in the pipeline makes reference to data in the buffer object being updated by `glBufferSubData`, especially from the specific region being updated, that rendering must drain from the pipeline before the data store can be updated.

Clients must align data elements consistent with the requirements of the client platform, with an additional base-level requirement that an offset within a buffer to a datum comprising N bytes be a multiple of N.

## Errors

`GL_INVALID_ENUM` is generated if target is not `GL_ARRAY_BUFFER` or `GL_ELEMENT_ARRAY_BUFFER`.

`GL_INVALID_VALUE` is generated if offset or size is negative, or if together they define a region of memory that extends beyond the buffer object's allocated data store.

`GL_INVALID_OPERATION` is generated if the reserved buffer object name 0 is bound to target.

## See Also

glBindBuffer, glBufferData

## Copyright

Copyright 2003-2004 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.