On 08/23/2014 12:59 PM, Le_Forgeron wrote:
>
> You should use fraction, it is simpler and not limited in precision
> (well, let povray handles that point).
>
> Tiling 23 is using 3 tiles, how do you split 1.0 in 3 parts of same
> size, when the underluying arithmetic is bound to binary representation ?
>
> Now, maybe an update of the scenes/textures/patterns/tiling.pov example ?
>
Agree, all good points. I admit to just using the tiling.pov's WriteMap 
feature to get the maps in large part because I didn't understand how 
the tiling pattern worked.

... I used this feature of the example
// change to yes to write the color_map to a text file
#declare WriteMap = no;
...

The quick fix to tiling.pov for the WriteMap feature above is just :

71,72c71,72
<             #write (MapFile, "    [", str(V2/TileTypes,5,4)," rgb <", 
vstr(3, ThisColor,", ", 0,4),">]\n")
<             #write (MapFile, "    [", str((V2+incre)/TileTypes,5,4)," 
rgb <", vstr(3, ThisColor,", ", 0,4),">]\n")
---
 >             #write (MapFile, "    [", str(V2/TileTypes,5,7)," rgb <", 
vstr(3, ThisColor,", ", 0,4),">]\n")
 >             #write (MapFile, "    [", str((V2+incre)/TileTypes,5,7)," 
rgb <", vstr(3, ThisColor,", ", 0,4),">]\n")

Even getting the color tiles I expect, I still don't understand 
everything about this tiling pattern. I didn't expect the pattern to 
plateau (or perhaps it peaks and recedes) inside the tiles? Rather I 
thought there would be a continued gradient to the center making 
impossible the sensitivity to mathematical noise in the map we see.

I'll see if tomorrow I can find some time to update so a fractional 
representation map is written to the WriteMap file instead of the fix 
above. Perhaps too adjusting the break points slightly more away from 
the apparent calk/tile edges of the pattern if I can get a better 
understanding of the gradients. Guess I can plot the whole thing as one 
gradient to better see what it is really doing in the tiles.

Bill P.

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