glPolygonOffset — set the scale and units used to calculate depth values
void glPolygonOffset(
|
GLfloat factor, |
GLfloat units); |
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.
When GL_POLYGON_OFFSET_FILL 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.
glPolygonOffset is useful for applying decals.
glIsEnabled with argument
GL_POLYGON_OFFSET_FILL.
glGet with argument GL_POLYGON_OFFSET_FACTOR or
GL_POLYGON_OFFSET_UNITS.
| OpenGL ES API Version | ||||
|---|---|---|---|---|
| Function Name | 2.0 | 3.0 | 3.1 | 3.2 |
| glPolygonOffset | ✔ | ✔ | ✔ | ✔ |
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