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gl_SampleID.3G - Man Page

contains the index of the sample currently being processed


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 Name1.101.201.301.401.503.304.

See Also

gl_SamplePosition(), gl_NumSamples()

Referenced By

gl_NumSamples.3G(3), gl_SampleMask.3G(3), gl_SampleMaskIn.3G(3), gl_SamplePosition.3G(3).