A Boolean value that indicates whether lighting is calculated for both sides of a primitive.
- iOS 5.0+
- macOS 10.8+
- tvOS 9.0+
If the value is
GL_TRUE and the back face of a primitive is being rendered, the lighting values are calculated by negating the surface normals for the primitive. If the value is
GL_FALSE, then the facing of the primitive is ignored when performing the lighting calculation. The default value is
Setting the value of this property to
GL_TRUE may impact performance. Only use two-sided lighting when either side of a primitive could theoretically be visible to the camera.