Just wanted to let you know that this procedure works really fine. I
extended it a bit to be able to use ZBrush/Mudbox style udims as well.
Thanks again.
Am Montag, 2. Februar 2015 21:11:19 UTC+1 schrieb Larry Gritz:
>
> (CC'ing osl-dev because the fun part of this is on the OSL side.)
>
>
> On Feb 2, 2015, at 11:52 AM, haggi krey <[email protected] <javascript:>>
> wrote:
>
> > I am reading image files with OIIO in my texure system.
> > Is it possible to use udim tiled textures from Mari, Mudbox or Zbrush
> with OIIO?
> > And if yes, how? Do I have to implement the reading of the correct file
> name by myself in my texture file osl shader or are there any helpful
> procedures in OIIO?
>
>
> You need to generate the texture name based on the coordinates:
>
> umap = int(s);
> vmap = int(t);
> udim = 1001 + 10*vmap + umap;
> filename = format ("%s%04d.tx", basename, udim);
>
> look up texture (filename, s-umap, t-vmap, ...)
>
> or, if your v's are all upside down, then 1.0 - (t-vmap).
>
> BUT... if you are using this from OSL (I'm presuming, because I see you on
> the mail list there frequently), the repeated calls to create strings on
> every shade will be a bottleneck. But there's a special trick to make it
> super fast and fully constant folded!
>
>
> shader
> udimtexture (string basename = "",
> float s = 0 [[int lockgeom = 0]],
> float t = 0 [[int lockgeom = 0]],
> output color Cout = 0)
> {
> #define NAME(i) format("%s%d.tx",basename,i+1001)
> #define TENNAMES(j)
> NAME(10*j+0),NAME(10*j+1),NAME(10*j+2),NAME(10*j+3),NAME(10*j+4), \
>
> NAME(10*j+5),NAME(10*j+6),NAME(10*j+7),NAME(10*j+8),NAME(10*j+9)
> #define TENROWS
> TENNAMES(0),TENNAMES(1),TENNAMES(2),TENNAMES(3),TENNAMES(4), \
>
> TENNAMES(5),TENNAMES(6),TENNAMES(7),TENNAMES(8),TENNAMES(9)
>
> string filenames[100] = { TENROWS };
> // The magic here is that the 'format' calls, since their parameters
> in this
> // macro expansion are all constant, will be constant-folded at
> runtime, and thus
> // the entire filenames[] array will become just constant memory that
> is initialized
> // just once, NOT every time the shader executes.
> // NOTE: if you expect more than 10 rows in v, adjust the above as
> needed.
>
> #undef NAME
> #undef TENNAME
> #undef TENROW
>
> int umap = int(s);
> int vmap = int(t);
> int udim = 1001 + 10*vmap + umap;
> string filename = filenames[udim]; // MAGIC! just an array lookup,
> no format calls
> Cout = texture (filename, s-umap, 1.0 - (t-vmap));
> }
>
>
>
>
>
> --
> Larry Gritz
> [email protected] <javascript:>
>
>
>
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