Index for Section 3G

Alphabetical listing for G

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glPolygonOffset(3G)
NAME
  glPolygonOffset - set the scale and units used to calculate depth values

SYNOPSIS
  void glPolygonOffset(
	  GLfloat factor,
	  GLfloat units );

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.

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 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.

NOTES
  glPolygonOffset() is available only if the GL version is 1.1 or greater.

  glPolygonOffset() has no effect on depth coordinates placed in the feedback
  buffer.

  glPolygonOffset() has no effect on selection.

ERRORS
  GL_INVALID_OPERATION is generated if glPolygonOffset() is executed between
  the execution of glBegin() and the corresponding execution of glEnd().

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 or GL_POLYGON_OFFSET_UNITS.

SEE ALSO
  glDepthFunc(3), glEnable(3), glGet(3), glIsEnabled(3)

Index for Section 3G

Alphabetical listing for G

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