Name

gl_SampleID — contains the index of the sample currently being processed

Declaration

in int gl_SampleID;

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

VariableVersion 1.10Version 1.20Version 1.30Version 1.40Version 1.50Version 3.30Version 4.00Version 4.10Version 4.20Version 4.30
gl_SampleID------YYYY

See Also

gl_SamplePosition, gl_NumSamples

Copyright

Copyright © 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/.