I've been noticing that it takes v3.5b1 up to 58 times as long as
MegaPOV 0.6 to render the same parametric object. The speed difference
is more extreme in more complex scenes. In the simple scene below,
MegaPOV is only 17 times faster.

I've been converting the scenes for my Isosurface Tutorial web page, and
this is a simplified version of one of them. MegaPOV 0.6 renders the
unconverted scene in 25 seconds, v3.5b1 takes 444 seconds to produce an
identical image. (320x240 No AA in both cases)

I know I can speed it up by a factor of 3 by adding a suitable
precompute, but the magnitude of the speed difference, and the fact that
3.5b1 tends to be faster in other areas, suggests to me that there may
well be a performance bug in the parametric code somewhere.


POV 3.5b1, Windows 98se, AMD K6-2 500, 128 Mb


camera { location  <2, 2, -8> look_at <0, 0, 0> angle 30}

light_source {<100,200,-100> colour rgb 1}

parametric {
  function {sin(u)}
  function {cos(u)}
  function {v}
      <0,-2>,<2*pi,2>
  contained_by{ box {<-2,-2,-2>,<2,2,2>}}
  pigment {rgb 0.9}
}

=======
// MegaPOV version of the same scene

#version unofficial MegaPov 0.6;

camera { location  <2, 2, -8> look_at <0, 0, 0> angle 30}

light_source {<100,200,-100> colour rgb 1}

parametric {
  function sin(u), cos(u), v
      <0,-2>,<2*pi,2>
      <-2,-2,-2>,<2,2,2>
  pigment {rgb 0.9}
}

-- 
Mike Williams
Gentleman of Leisure

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