clipka <ano### [at] anonymousorg> wrote:
> Am 15.11.2012 17:43, schrieb Bruno Cabasson:
>
> >> POV-Ray does not seem suited to single precision.  Perhaps it is the nature of
> >> mathematically defined shapes that they require higher precision than mesh-based
> >> systems.
> >
> > Meshes also involve maths ...
>
> Mesh math is pretty trivial, requiring only linear equations to be
> solved. But even a seemingly simple thing as a sphere already involves
> quadratic equations, and cubic equations aren't uncommon in POV-Ray
> either. Some primitives require even higher-order polynomials.
>
> And the higher the order of a polynomial, the higher the dynamic range
> needed to solve it.

Let me put it differently. Since today's GPUs' native format is single
precision, which is much faster than their emulated double precision (AFAIK),
and if POV-Ray were to use GPU or hardware-accelrated computing (one day ...,
see a recent post on the subject), I was curious to know where double precision
is really necessary.

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