GL_SAMPLEID(3G)

NAME
gl_SampleID - contains the index of the sample currently being processed

DECLARATION
in int gl_SampleID ;.SH "DESCRIPTION"

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.

When rendering to a non-multisample buffer, or if multisample rasterization is disabled, gl_SampleID will always be zero. gl_NumSamples() is the sample count of the framebuffer regardless of whether multisample rasterization is enabled or not.

VERSION SUPPORT
 | OpenGL Shading Language Version
Variable Name | 1.10 | 1.20 | 1.30 | 1.40 | 1.50 | 3.30 | 4.00 | 4.10 | 4.20 | 4.30 | 4.40 | 4.50 | 4.60
gl_SampleID | - | - | - | - | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔

SEE ALSO

gl_SamplePosition(), gl_NumSamples()

COPYRIGHT

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. https://opencontent.org/openpub/.

COPYRIGHT
Copyright © 2011-2014 Khronos Group