[PATCH 3/8] wined3d: Implement SM5 deriv_rtx_coarse instruction.

[Józef Kucia]

On Tue, Jul 26, 2016 at 1:41 AM, Matteo Bruni <matteo.mystral at gmail.com> wrote:
> What about using the generic dFdx()/dFdy() builtins (maybe with a
> WARN) for the coarse and fine variants when ARB_derivative_control
> isn't supported?
> I don't know that it's particularly relevant in practice, it just
> seems something we don't need to strictly depend on.

I have no idea if this is issue in practice but wined3d currently
requires ARB_derivative_control for SM5. I guess we can add a fallback
to dFdx()/dFdy() if we find an OpenGL implementation which is
otherwise capable to support SM5 but doesn't expose
ARB_derivative_control.