Gl.PolygonOffset (gb.opengl)
Static Sub PolygonOffset ( Factor As Float, Units As Float )
Set the scale and units used to calculate depth values.
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
,
where
is a measurement of the change in depth relative to the screen
area of the polygon, and
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.
Gl.PolygonOffset is useful for rendering hidden-line images, for applying decals
to surfaces, and for rendering solids with highlighted edges.
Associated Gets
Gl.IsEnabled with argument
Gl.POLYGON_OFFSET_FILL,
Gl.POLYGON_OFFSET_LINE,
or
Gl.POLYGON_OFFSET_POINT.
Gl.Get with argument
Gl.POLYGON_OFFSET_FACTOR or
Gl.POLYGON_OFFSET_UNITS.
See also
Gl.Enable
Gl.Get
Gl.IsEnabled