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 |
| glPolygonOffset | ✔ | ✔ | ✔ |
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