Name

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, 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.

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

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 N bytes be a multiple of N.

Errors

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.

Associated Gets

glGetBufferSubData

See Also

glBindBuffer, glBufferData, glMapBuffer, glUnmapBuffer

Copyright

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/.