GLREADBUFFER(3G)

  .SH "NAME" glReadBuffer, glNamedFramebufferReadBuffer - select a color buffer source for pixels
  .SH "C SPECIFICATION"

      .HP u void glReadBuffer(GLenum mode);
      .HP u void glNamedFramebufferReadBuffer(GLuint framebuffer, GLenum mode);

  .SH "PARAMETERS"

      .PP framebuffer

              Specifies the name of the framebuffer object for glNamedFramebufferReadBuffer function.

          .RE
          .PP 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.

              .RE

          .SH "DESCRIPTION"

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

          .SH "ERRORS"

            .PP GL_INVALID_ENUM is generated if mode is not one of the twelve (or more) accepted values.
            .PP GL_INVALID_OPERATION is generated if mode specifies a buffer that does not exist.
            .PP GL_INVALID_OPERATION is generated by glNamedFramebufferReadBuffer if framebuffer is not zero or the name of an existing framebuffer object.

          .SH "ASSOCIATED GETS"

            .PP glGet() with argument GL_READ_BUFFER

            .SH "VERSION SUPPORT"
                .TS allbox tab(:); lB cB s s s s s s s s s s s lB cB cB cB cB cB cB cB cB cB cB cB cB. T{ T}:T{ OpenGL Version T} T{ Function / Feature Name T}:T{ 2.0 T}:T{ 2.1 T}:T{ 3.0 T}:T{ 3.1 T}:T{ 3.2 T}:T{ 3.3 T}:T{ 4.0 T}:T{ 4.1 T}:T{ 4.2 T}:T{ 4.3 T}:T{ 4.4 T}:T{ 4.5 T} l c c c c c c c c c c c c l c c c c c c c c c c c c. T{ glNamedFramebufferReadBuffer T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ - T}:T{ ✔ T} T{ glReadBuffer T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}:T{ ✔ T}

            .SH "SEE ALSO"
                .PP glCopyTexImage1D(), glCopyTexImage2D(), glCopyTexSubImage1D(), glCopyTexSubImage2D(), glCopyTexSubImage3D(), glDrawBuffer(), glReadPixels()

            .SH "COPYRIGHT"
                .PP 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 https://khronos.org/registry/OpenGL-Refpages/LICENSES/LicenseRef-FreeB.txt.

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