Native bindings to the OES_sample_shading extension.

In standard multisample rendering, an implementation is allowed to assign the same sets of fragment shader input values to each sample. This can cause aliasing where the fragment shader input values are used to generate a result that doesn't antialias itself, for example with alpha-tested transparency.

This extension adds the ability to explicitly request that an implementation use a minimum number of unique set of fragment computation inputs when multisampling a pixel. Specifying such a requirement can reduce aliasing that results from evaluating the fragment computations too few times per pixel.

This extension adds new global state that controls the minimum number of samples for which attribute data is independently interpolated. When enabled, all fragment-shading operations are executed independently on each sample.

Requires GLES 3.0.