gl_SampleMaskIn - contains the computed sample coverage mask for the current fragment

       Copyright © 2011-2014 Khronos Group

[FIXME: source]                                    11/18/2024                                GL_SAMPLEMASKIN(3G)

       in int gl_SampleMaskIn[] ;.SH "DESCRIPTION"

       gl_SampleMaskIn is a fragment language that indicates the set of samples covered by the primitive
       generating the fragment during multisample rasterization. It has a sample bit set if and only if the
       sample is considered covered for this fragment shader invocation. Bit B of mask gl_SampleMask[M]
       corresponds to sample 32 * M + B. The array has ceil(s / 32) elements where s is the maximum number of
       color samples supported by the implementation.

       gl_SampleMaskIn - contains the computed sample coverage mask for the current fragment

gl_SampleMask(), gl_SampleID(), gl_SamplePosition(), gl_FragCoord()

       ┌─────────────────┬───────────────────────────────────────────────────────────────────────────────────┐
       │                 │        OpenGLShadingLanguageVersion                                            │
       ├─────────────────┼──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┬──────┤
       │ Variable        │ 1.10 │ 1.20 │ 1.30 │ 1.40 │ 1.50 │ 3.30 │ 4.00 │ 4.10 │ 4.20 │ 4.30 │ 4.40 │ 4.50 │
       │ Name            │      │      │      │      │      │      │      │      │      │      │      │      │
       ├─────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┼──────┤
       │ gl_SampleMaskIn │  -   │  -   │  -   │  -   │  -   │  -   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │
       └─────────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘