GLPOLYGONOFFSETCLAMP(3G)

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💅 GLPOLYGONOFFSETCLAMP (3G) — okay bestie, let's talk depth offsets

Hey so this is a page from the 3G manual family, and it's about glPolygonOffsetClamp — the function that sets the scale, units and clamp used to calculate depth values. It's giving "niche but iconic" ngl. 🦋

✨ NAME ✨

glPolygonOffsetClamp — set the scale, units and clamp used to calculate depth values 💖

🌸 C SPECIFICATION 🌸

void glPolygonOffsetClamp(GLfloat factor, GLfloat units, GLfloat clamp);

Literally that's the whole signature. Three GLfloats and you're done. Slay. ✨

🎀 PARAMETERS 🎀

  • 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.
  • clamp — Used to set a maximum or minimum value for the offset calculation.
So factor and units both start at 0, and clamp is the new main character that lets you cap the whole thing. Periodt. 👑

💜 DESCRIPTION 💜

Okay so 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 offset is calculated as follows:

o = { factor × DZ + r × units , clamp = 0 or NaN
      min ( factor × DZ + r × units , clamp ) , clamp > 0
      max ( factor × DZ + r × units , clamp ) , clamp < 0

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. Like, the order matters, bestie, don't skip steps. 🫶

glPolygonOffsetClamp is useful for rendering hidden-line images, for applying decals to surfaces, and for rendering solids with highlighted edges. It's giving glow-up for your geometry. 🔥

🧚 ASSOCIATED GETS 🧚

  • glIsEnabled() with argument GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT.
  • glGet() with argument GL_POLYGON_OFFSET_FACTOR, GL_POLYGON_OFFSET_UNITS or POLYGON_OFFSET_CLAMP.

(Yes, POLYGON_OFFSET_CLAMP is written without the GL_ prefix there. That's exactly what the page says, so I'm keeping it exactly as-is. I don't make the rules. 🙈)

🌈 VERSION SUPPORT 🌈

So the original has a whole grid, and the vibe check is: only one version supports this function. Everyone else is a no. 😭

  • The columns are the OpenGL versions: 2.0, 2.1, 3.0, 3.1, 3.2, 3.3, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6.
  • Row label: Function / Feature Name → glPolygonOffsetClamp.
  • glPolygonOffsetClamp under 2.0: -
  • under 2.1: -
  • under 3.0: -
  • under 3.1: -
  • under 3.2: -
  • under 3.3: -
  • under 4.0: -
  • under 4.1: -
  • under 4.2: -
  • under 4.3: -
  • under 4.4: -
  • under 4.5: -
  • under 4.6: ✔

So yeah — if you're not on 4.6, this function is not your moment. 💀 The ✔ is doing a lot of heavy lifting for one single column and honestly? Respect. 👑

⭐ SEE ALSO ⭐

  • glPolygonOffset()
  • glDepthFunc()
  • glEnable()
  • glGet()
  • glIsEnabled()

Go read those next, bestie, iykyk. 🦋

Copyright © 1991-2006 Silicon Graphics, Inc. Copyright © 2010-2014 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see https://khronos.org/registry/OpenGL-Refpages/LICENSES/LicenseRef-FreeB.txt.

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

🍓 Okay and that's the whole page! Source/version is [FIXME: source] and the date is 10/07/2026 — so yeah, this was assembled by the [FIXME] crew, dated October 7, 2026, and stamped GLPOLYGONOFFSETCLAMP(3G) on both ends. Take care of yourself, hydrate, and remember: clamp your offsets responsibly. 🧚✨💅
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