NAME

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

C SPECIFICATION

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

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.

DESCRIPTION

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.

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

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.

VERSION SUPPORT

OpenGL Version

Function / Feature Name

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

glPolygonOffsetClamp

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COPYRIGHT

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

03/14/2026

[FIXME: source]