glPolygonOffset - set the scale and units used to calculate depth values

glIsEnabled() with argument GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT.

       glGet() with argument GL_POLYGON_OFFSET_FACTOR or GL_POLYGON_OFFSET_UNITS.

voidglPolygonOffset(GLfloatfactor,GLfloatunits);

       Copyright © 1991-2006 Silicon Graphics, Inc.
       Copyright © 2010-2014 Khronos Group

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

       When GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT is enabled, each
       fragment's depth value will be offset after it is interpolated from the depth values of the appropriate
       vertices. The value of the offset is factor × DZ + r × units, where DZ is a measurement of the change in
       depth relative to the screen area of the polygon, and r is the smallest value that is guaranteed to
       produce a resolvable offset for a given implementation. The offset is added before the depth test is
       performed and before the value is written into the depth buffer.

       glPolygonOffset is useful for rendering hidden-line images, for applying decals to surfaces, and for
       rendering solids with highlighted edges.

       glPolygonOffset - set the scale and units used to calculate depth values

factor
           Specifies a scale factor that is used to create a variable depth offset for each polygon. The initial
           value is 0.

       units
           Is multiplied by an implementation-specific value to create a constant depth offset. The initial
           value is 0.

glDepthFunc(), glEnable(), glGet(), glIsEnabled()

       ┌─────────────────┬───────────────────────────────────────────────────────────────────────┐
       │                 │                OpenGLVersion                                         │
       ├─────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
       │ Function        │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
       │ /               │     │     │     │     │     │     │     │     │     │     │     │     │
       │ Feature         │     │     │     │     │     │     │     │     │     │     │     │     │
       │ Name            │     │     │     │     │     │     │     │     │     │     │     │     │
       ├─────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │ glPolygonOffset │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │  ✔  │
       └─────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘