NAME

       glReadBuffer, glNamedFramebufferReadBuffer - select a color buffer source for pixels

C SPECIFICATION

       void glReadBuffer(GLenum mode);

       void glNamedFramebufferReadBuffer(GLuint framebuffer, GLenum mode);

PARAMETERS

       framebuffer
           Specifies the name of the framebuffer object for glNamedFramebufferReadBuffer
           function.

       mode
           Specifies a color buffer. Accepted values are GL_FRONT_LEFT, GL_FRONT_RIGHT,
           GL_BACK_LEFT, GL_BACK_RIGHT, GL_FRONT, GL_BACK, GL_LEFT, GL_RIGHT, and the constants
           GL_COLOR_ATTACHMENTi.

DESCRIPTION

       glReadBuffer specifies a color buffer as the source for subsequent glReadPixels(),
       glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(), and
       glCopyTexSubImage3D() commands.  mode accepts one of twelve or more predefined values. In
       a fully configured system, GL_FRONT, GL_LEFT, and GL_FRONT_LEFT all name the front left
       buffer, GL_FRONT_RIGHT and GL_RIGHT name the front right buffer, and GL_BACK_LEFT and
       GL_BACK name the back left buffer. Further more, the constants GL_COLOR_ATTACHMENTi may be
       used to indicate the ith color attachment where i ranges from zero to the value of
       GL_MAX_COLOR_ATTACHMENTS minus one.

       Nonstereo double-buffered configurations have only a front left and a back left buffer.
       Single-buffered configurations have a front left and a front right buffer if stereo, and
       only a front left buffer if nonstereo. It is an error to specify a nonexistent buffer to
       glReadBuffer.

       mode is initially GL_FRONT in single-buffered configurations and GL_BACK in
       double-buffered configurations.

       For glReadBuffer, the target framebuffer object is that bound to GL_READ_FRAMEBUFFER. For
       glNamedFramebufferReadBuffer, framebuffer must either be zero or the name of the target
       framebuffer object. If framebuffer is zero, then the default read framebuffer is affected.

ERRORS

       GL_INVALID_ENUM is generated if mode is not one of the twelve (or more) accepted values.

       GL_INVALID_OPERATION is generated if mode specifies a buffer that does not exist.

       GL_INVALID_OPERATION is generated by glNamedFramebufferReadBuffer if framebuffer is not
       zero or the name of an existing framebuffer object.

ASSOCIATED GETS

       glGet() with argument GL_READ_BUFFER

VERSION SUPPORT

       ┌─────────────────────────────┬───────────────────────────────────────────────────────────────────────┐
       │                             │                OpenGL Version                                         │
       ├─────────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
       │Function                     │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
       │/                            │     │     │     │     │     │     │     │     │     │     │     │     │
       │Feature                      │     │     │     │     │     │     │     │     │     │     │     │     │
       │Name                         │     │     │     │     │     │     │     │     │     │     │     │     │
       ├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │glNamedFramebufferReadBuffer │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │
       ├─────────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │glReadBuffer                 │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │
       └─────────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘

SEE ALSO

       glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(),
       glCopyTexSubImage3D(), glDrawBuffer(), glReadPixels()

COPYRIGHT

       Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2011-2014 Khronos Group. This
       document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

COPYRIGHT

       Copyright © 1991-2006 Silicon Graphics, Inc.
       Copyright © 2011-2014 Khronos Group

[FIXME: source]                             01/03/2018                           GLREADBUFFER(3G)