glBufferSubData — updates a subset of a buffer object's data store
void glBufferSubData( | GLenum | target, |
GLintptr | offset, | |
GLsizeiptr | size, | |
const GLvoid * | data) ; |
target
Specifies the target buffer object.
The symbolic constant must be GL_ARRAY_BUFFER
,
GL_ELEMENT_ARRAY_BUFFER
,
GL_PIXEL_PACK_BUFFER
, or
GL_PIXEL_UNPACK_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.
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.
glBufferSubData
is available only if the GL version is 1.5 or greater.
Targets GL_PIXEL_PACK_BUFFER
and GL_PIXEL_UNPACK_BUFFER
are available
only if the GL version is 2.1 or greater.
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
GL_INVALID_ENUM
is generated if target
is not
GL_ARRAY_BUFFER
, GL_ELEMENT_ARRAY_BUFFER
,
GL_PIXEL_PACK_BUFFER
, or GL_PIXEL_UNPACK_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
.
GL_INVALID_OPERATION
is generated if the buffer object being updated is mapped.
GL_INVALID_OPERATION
is generated if glBufferSubData
is executed between the execution of
glBegin and the corresponding execution of
glEnd.
Copyright © 2005 Addison-Wesley. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.