glMapBuffer man page on RedHat

Man page or keyword search:  
man Server   29550 pages
apropos Keyword Search (all sections)
Output format
RedHat logo
[printable version]

GLMAPBUFFER(3G)			 OpenGL Manual		       GLMAPBUFFER(3G)

NAME
       glMapBuffer - map a buffer object's data store

C SPECIFICATION
       void * glMapBuffer(GLenum target, GLenum access);

PARAMETERS
       target
	   Specifies the target buffer object being mapped. The symbolic
	   constant must be GL_ARRAY_BUFFER, GL_ATOMIC_COUNTER_BUFFER,
	   GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_DRAW_INDIRECT_BUFFER,
	   GL_DISPATCH_INDIRECT_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
	   GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER,
	   GL_SHADER_STORAGE_BUFFER, GL_TEXTURE_BUFFER,
	   GL_TRANSFORM_FEEDBACK_BUFFER or GL_UNIFORM_BUFFER.

       access
	   Specifies the access policy, indicating whether it will be possible
	   to read from, write to, or both read from and write to the buffer
	   object's mapped data store. The symbolic constant must be
	   GL_READ_ONLY, GL_WRITE_ONLY, or GL_READ_WRITE.

C SPECIFICATION
       GLboolean glUnmapBuffer(GLenum target);

PARAMETERS
       target
	   Specifies the target buffer object being unmapped. The symbolic
	   constant must be GL_ARRAY_BUFFER, GL_ATOMIC_COUNTER_BUFFER,
	   GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_DRAW_INDIRECT_BUFFER,
	   GL_DISPATCH_INDIRECT_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
	   GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER,
	   GL_SHADER_STORAGE_BUFFER, GL_TEXTURE_BUFFER,
	   GL_TRANSFORM_FEEDBACK_BUFFER or GL_UNIFORM_BUFFER.

DESCRIPTION
       glMapBuffer maps to the client's address space the entire data store of
       the buffer object currently bound to target. The data can then be
       directly read and/or written relative to the returned pointer,
       depending on the specified access policy. If the GL is unable to map
       the buffer object's data store, glMapBuffer generates an error and
       returns NULL. This may occur for system-specific reasons, such as low
       virtual memory availability. If no error occurs, the returned pointer
       will have an alignment of at least GL_MIN_MAP_BUFFER_ALIGNMENT basic
       machine units. The value of GL_MIN_MAP_BUFFER_ALIGNMENT can be
       retrieved by calling glGet() with pname set to
       GL_MIN_MAP_BUFFER_ALIGNMENT and must be a power of two that is at least
       64.

       If a mapped data store is accessed in a way inconsistent with the
       specified access policy, no error is generated, but performance may be
       negatively impacted and system errors, including program termination,
       may result. Unlike the usage parameter of glBufferData, access is not a
       hint, and does in fact constrain the usage of the mapped data store on
       some GL implementations. In order to achieve the highest performance
       available, a buffer object's data store should be used in ways
       consistent with both its specified usage and access parameters.

       A mapped data store must be unmapped with glUnmapBuffer before its
       buffer object is used. Otherwise an error will be generated by any GL
       command that attempts to dereference the buffer object's data store.
       When a data store is unmapped, the pointer to its data store becomes
       invalid.	 glUnmapBuffer returns GL_TRUE unless the data store contents
       have become corrupt during the time the data store was mapped. This can
       occur for system-specific reasons that affect the availability of
       graphics memory, such as screen mode changes. In such situations,
       GL_FALSE is returned and the data store contents are undefined. An
       application must detect this rare condition and reinitialize the data
       store.

       A buffer object's mapped data store is automatically unmapped when the
       buffer object is deleted or its data store is recreated with
       glBufferData.

NOTES
       If an error is generated, glMapBuffer returns NULL, and glUnmapBuffer
       returns GL_FALSE.

       Parameter values passed to GL commands may not be sourced from the
       returned pointer. No error will be generated, but results will be
       undefined and will likely vary across GL implementations.

       Alignment of the returned pointer is guaranteed only if the version of
       the GL version is 4.2 or greater. Also, the GL_ATOMIC_COUNTER_BUFFER
       target is accepted only if the GL version is 4.2 or greater.

       The GL_DISPATCH_INDIRECT_BUFFER and GL_SHADER_STORAGE_BUFFER targets
       are available only if the GL version is 4.3 or greater.

ERRORS
       GL_INVALID_ENUM is generated if target is not one of the accepted
       targets.

       GL_INVALID_ENUM is generated if access is not GL_READ_ONLY,
       GL_WRITE_ONLY, or GL_READ_WRITE.

       GL_OUT_OF_MEMORY is generated when glMapBuffer is executed if the GL is
       unable to map the buffer object's data store. This may occur for a
       variety of system-specific reasons, such as the absence of sufficient
       remaining virtual memory.

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

       GL_INVALID_OPERATION is generated if glMapBuffer is executed for a
       buffer object whose data store is already mapped.

       GL_INVALID_OPERATION is generated if glUnmapBuffer is executed for a
       buffer object whose data store is not currently mapped.

ASSOCIATED GETS
       glGetBufferPointerv() with argument GL_BUFFER_MAP_POINTER

       glGetBufferParameter() with argument GL_BUFFER_MAPPED,
       GL_BUFFER_ACCESS, or GL_BUFFER_USAGE

SEE ALSO
       glBindBuffer(), glBindBufferBase(), glBindBufferRange(),
       glBufferData(), glBufferSubData(), glDeleteBuffers()

COPYRIGHT
       Copyright © 2005 Addison-Wesley. Copyright © 2010-2011 Khronos Group.
       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/.

AUTHORS
       opengl.org

opengl.org			  03/16/2013		       GLMAPBUFFER(3G)
[top]

List of man pages available for RedHat

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net