gl_SampleID.3G man page

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

gl_SampleID

See Also

gl_SamplePosition(), gl_NumSamples()

Info

02/04/2016 [FIXME: source] [FIXME: manual]