2005 Sams Publishing glGetBufferSubData 3G glGetBufferSubData returns a subset of a buffer object's data store void glGetBufferSubData GLenum target GLintptr offset GLsizeiptr size GLvoid * data target Specifies the target buffer object. The symbolic constant 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_TEXTURE_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER, or GL_UNIFORM_BUFFER. offset Specifies the offset into the buffer object's data store from which data will be returned, measured in bytes. size Specifies the size in bytes of the data store region being returned. data Specifies a pointer to the location where buffer object data is returned. glGetBufferSubData returns some or all of the data from the buffer object currently bound to target. Data starting at byte offset offset and extending for size bytes is copied from the data store to the memory pointed to by data. An error is thrown if the buffer object is currently mapped, or if offset and size together define a range beyond the bounds of the buffer object's data store. If an error is generated, no change is made to the contents of data. 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 queried is mapped. glBindBuffer, glBufferData, glBufferSubData, glMapBuffer, glUnmapBuffer 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/.