Boring! Hmm wait a second it doesn't look like MegaPOV :-)

As I finally got beta31 compiled yesterday evening and some
people recently posted that the AOI pattern is one of the most
useful things in MegaPOV I thought porting this to the 3.7
codebase would be a realistic aim for familiarizing myself
with the sources. All in all, it went rather smoothly, it
could have worked yesterday night if I hadn't been so
sleepy as to move a block to Parse_PatternFunction
which should have been in Parse_Pattern.

Of course, it needs some testing and then some probing
in the beta test group whether the POV-Team is actually
interested to include this in 3.7.

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Preview of image 'testaoi.png'

The MegaPOV examples scene pat_aoi.pov rendered in my patched 3.7b31

It's not 100% identical to the MegaPOV render but that was to
be expected for a radiosity scene. Without radiosity I did not
see any difference.

If anyone has some made some nifty trick using the aoi
pattern and wishes to provide the scene file I'd be happy
to test whether it works.

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Attachments:
Download 'pat_aoi1-37b31.png' (238 KB)

Preview of image 'pat_aoi1-37b31.png'

Christian Froeschlin <chr### [at] chrfrde> wrote:
> The MegaPOV examples scene pat_aoi.pov rendered in my patched 3.7b31
>
> It's not 100% identical to the MegaPOV render but that was to
> be expected for a radiosity scene. Without radiosity I did not
> see any difference.
>
> If anyone has some made some nifty trick using the aoi
> pattern and wishes to provide the scene file I'd be happy
> to test whether it works.

I don't have the test scene on hand, but I have had an issue with the way the
aoi pattern worked in the past.  The issue arises when you transform an object
with the aoi pattern - it has a tendency to transform the provided aoi vector,
which may not be what you want.  It would be nice if the vector could somehow
be specified as a direction relative to the object, not absolute.


-Reactor

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Reactor wrote:

> The issue arises when you transform an object
> with the aoi pattern - it has a tendency to transform the provided aoi vector,

Or rather *not* to transform the aoi vector, while you expect
it to move with the object? At first glance, it looks like the
transforms are only used to warp the point at which the texture
will be evaluated, parameters of the texture are not adapted.
I just tried a "slope y" texture, apply this to an object
and rotate it and the slope reference will still be y.

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Christian Froeschlin <chr### [at] chrfrde> wrote:
> Or rather *not* to transform the aoi vector, while you expect
> it to move with the object? At first glance, it looks like the
> transforms are only used to warp the point at which the texture
> will be evaluated, parameters of the texture are not adapted.
> I just tried a "slope y" texture, apply this to an object
> and rotate it and the slope reference will still be y.

Both may be the way you'd need it at times. Maybe even for the very same object
& pattern: In an object assembled from smaller building blocks, it may be
desired to orient the aoi pattern of all building blocks with reference to the
object, while when orienting the object those patterns should re-orient
accordingly.

Best thing would be if the reference point of an aoi pattern could somehow be
attached itself to a particular object... well, maybe that's something to
remember for next generation SDL.

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Christian Froeschlin <chr### [at] chrfrde> wrote:
> I just tried a "slope y" texture, apply this to an object
> and rotate it and the slope reference will still be y.

Actually, that's good news (for me at least). For some reason I imagined the
slope pattern would rotate around together with the object, so I went to great
length to make sure I got a uniform slope direction for a bunch of objects I
needed to rotate.
Now I can do some things in a different way.

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clipka wrote:

> Actually, that's good news (for me at least). For some reason I imagined the
> slope pattern would rotate around together with the object

yes, that's what I'd have still imagined yesterday, too ;)

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Christian Froeschlin <chr### [at] chrfrde> wrote:
> The MegaPOV examples scene pat_aoi.pov rendered in my patched 3.7b31
>
> It's not 100% identical to the MegaPOV render but that was to
> be expected for a radiosity scene. Without radiosity I did not
> see any difference.
>
> If anyone has some made some nifty trick using the aoi
> pattern and wishes to provide the scene file I'd be happy
> to test whether it works.

I've used it to vary the blurriness of reflectivity based on the viewing angle,
so using aoi for the micronormals (this example is a bit contrived, but shows
the effect I want):

// Render at 640x480 with AA set waaay up high
#version unofficial MegaPov 1.21;

camera { perspective location <1,0.67,-4> angle 45 look_at <0,1,0> }
light_source { <200,180,-200> rgb 1 }
plane { <0,1,0>, 0 pigment { checker rgb 1 rgb 0 } }

#declare normal_scale = 0.0001;
#declare blur_size = 0.08;

sphere {
 <0.0, 0.0, 0.0>, 1
 translate y*1

 pigment { rgb <1,0.1,0.7> }
 finish { reflection {0, 1 fresnel on} metallic }
 normal {
  aoi
  normal_map {
   [ 0.00, bumps blur_size*1.00 scale normal_scale ]
   [ 0.05, bumps blur_size*0.99 scale normal_scale ]
   [ 0.10, bumps blur_size*0.98 scale normal_scale ]
   [ 0.15, bumps blur_size*0.96 scale normal_scale ]
   [ 0.20, bumps blur_size*0.92 scale normal_scale ]
   [ 0.25, bumps blur_size*0.87 scale normal_scale ]
   [ 0.30, bumps blur_size*0.80 scale normal_scale ]
   [ 0.35, bumps blur_size*0.70 scale normal_scale ]
   [ 0.40, bumps blur_size*0.56 scale normal_scale ]
   [ 0.45, bumps blur_size*0.34 scale normal_scale ]
   [ 0.50, bumps 0 ]
  }
 }
 interior { ior 2.2 }
}

// Just to add some pretty
sky_sphere {
 pigment {
  gradient y
  color_map {
   // http://povray.tashcorp.net/tutorials/qd_realskysphere/
   [  0/269 color rgb <120/255, 79/255, 51/255>]
   [  1/269 color rgb <141/255, 83/255, 46/255>]
   [  2/269 color rgb <177/255, 86/255, 41/255>]
   [  3/269 color rgb <235/255,128/255, 72/255>]
   [  5/269 color rgb <255/255,159/255, 72/255>]
   [  8/269 color rgb <255/255,203/255, 94/255>]
   [ 10/269 color rgb <255/255,218/255,112/255>]
   [ 13/269 color rgb <255/255,233/255,148/255>]
   [ 15/269 color rgb <251/255,241/255,172/255>]
   [ 20/269 color rgb <255/255,246/255,203/255>]
   [ 30/269 color rgb <255/255,240/255,219/255>]
   [ 40/269 color rgb <236/255,223/255,214/255>]
   [ 50/269 color rgb <205/255,204/255,212/255>]
   [ 55/269 color rgb <185/255,190/255,209/255>]
   [ 60/269 color rgb <166/255,176/255,201/255>]
   [ 65/269 color rgb <149/255,163/255,190/255>]
   [ 70/269 color rgb <129/255,149/255,182/255>]
   [ 80/269 color rgb <103/255,127/255,171/255>]
   [ 90/269 color rgb < 79/255,110/255,154/255>]
   [100/269 color rgb < 66/255, 97/255,143/255>]
   [110/269 color rgb < 52/255, 84/255,131/255>]
   [120/269 color rgb < 47/255, 75/255,122/255>]
   [140/269 color rgb < 37/255, 60/255,102/255>]
   [160/269 color rgb < 32/255, 51/255, 84/255>]
   [180/269 color rgb < 27/255, 42/255, 71/255>]
   [200/269 color rgb < 25/255, 36/255, 58/255>]
   [220/269 color rgb < 22/255, 31/255, 48/255>]
   [240/269 color rgb < 18/255, 27/255, 42/255>]
   [260/269 color rgb < 15/255, 21/255, 33/255>]
   [269/269 color rgb < 15/255, 21/255, 33/255>]
  }
 }
}


Cheers,
Edouard.

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Christian Froeschlin <chr### [at] chrfrde> wrote:
> > Actually, that's good news (for me at least). For some reason I imagined the
> > slope pattern would rotate around together with the object
>
> yes, that's what I'd have still imagined yesterday, too ;)

.... so maybe strictly speaking it's bad because it is counter-intuitive?

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> I've used it to vary the blurriness of reflectivity based on the viewing angle

neat! I seem to get a reasonable result although maybe a bit
more grainy than yours. I used +a0.0 +r9, I don't know how to
get any higher ;) The jpg conversion may also be different.

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