gl_PatchVerticesIn - contains the number of vertices in the current patch

       Copyright © 2011-2014 Khronos Group

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

       in int gl_PatchVerticesIn ;.SH "DESCRIPTION"

       Available only in the tessellation control and evaluation languages, gl_PatchVerticesIn contains the
       number of vertices in the input being processed by the shader. A single tessellation control or
       evaluation shader can read patches of differing sizes, and so th value of gl_PatchVertexIn may differ
       between patches.

       gl_PatchVerticesIn - contains the number of vertices in the current patch

gl_TessLevelOuter(), gl_TessLevelInner(), gl_TessCoord()

       ┌────────────────────┬───────────────────────────────────────────────────────────────────────────────────┐
       │                    │        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_PatchVerticesIn │  -   │  -   │  -   │  -   │  -   │  -   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │  ✔   │
       └────────────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┴──────┘