# glCopyBufferSubData

## Name

glCopyBufferSubData — copy part of the data store of a buffer object to the data store of another buffer object

## C Specification

 void glCopyBufferSubData( GLenum readtarget, GLenum writetarget, GLintptr readoffset, GLintptr writeoffset, GLsizeiptr size);

## Parameters

readtarget

Specifies the target from whose data store data should be read.

writetarget

Specifies the target to whose data store data should be written.

readoffset

Specifies the offset, in basic machine units, within the data store of readtarget from which data should be read.

writeoffset

Specifies the offset, in basic machine units, within the data store of writetarget to which data should be written.

size

Specifies the size, in basic machine units, of the data to be copied from readtarget to writetarget.

## Description

glCopyBufferSubData copies part of the data store attached to readtarget to the data store attached to writetarget. The number of basic machine units indicated by size is copied from the source, at offset readoffset to the destination at writeoffset, also in basic machine units.

readtarget and writetarget must be GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER or GL_UNIFORM_BUFFER. Any of these targets may be used, although the targets GL_COPY_READ_BUFFER and GL_COPY_WRITE_BUFFER are provided specifically to allow copies between buffers without disturbing other GL state.

readoffset, writeoffset and size must all be greater than or equal to zero. Furthermore, readoffset + size must not exceeed the size of the buffer object bound to readtarget, and writeoffset + size must not exceeed the size of the buffer bound to writetarget. If the same buffer object is bound to both readtarget and writetarget, then the ranges specified by readoffset, writeoffset and size must not overlap.

## Errors

GL_INVALID_VALUE is generated if any of readoffset, writeoffset or size is negative, if readoffset + size exceeds the size of the buffer object bound to readtarget or if writeoffset + size exceeds the size of the buffer object bound to writetarget.

GL_INVALID_VALUE is generated if the same buffer object is bound to both readtarget and writetarget and the ranges [readoffset, readoffset + size) and [writeoffset, writeoffset + size) overlap.

GL_INVALID_OPERATION is generated if zero is bound to readtarget or writetarget.

GL_INVALID_OPERATION is generated if the buffer object bound to either readtarget or writetarget is mapped.

## API Version Support

OpenGL ES API Version
Function Name 2.0 3.0 3.1
glCopyBufferSubData -