GL_SAMPLEID(3G)

    .SH "NAME" gl_SampleID - contains the index of the sample currently being processed
    .SH "DECLARATION"

            in
            int
            gl_SampleID
        ;

    .SH "DESCRIPTION"
        .PP gl_SampleID is a fragment language input variable that contains the index of the sample currently being processed. This variable is in the range 0 to gl_NumSamples() - 1, where gl_NumSamples() is the total number of samples in each fragment for the current framebuffer (and thus 1 if rendering to a non-multisample buffer). Any static use of this variable in a fragment shader causes the entire shader to be evaluated per-sample rather than per-fragment.
        .PP When rendering to a non-multisample buffer, gl_SampleID will always be zero. gl_NumSamples() is the sample count of the framebuffer regardless of whether the framebuffer is multisampled or not.

    .SH "VERSION SUPPORT"
        .TS allbox tab(:); l l l l l. T{ gl_SampleID T}:T{ T}:T{ T}:T{ T}:T{ T}

    .SH "SEE ALSO"
        .PP gl_SamplePosition(), gl_NumSamples()

    .SH "COPYRIGHT"
        .PP Copyright © 2011-2014 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/.

COPYRIGHT
Copyright © 2011-2015 Khronos Group