RE: LANG: repeating textures

Adrian Scott (adrians@nafohq.hp.com)
Wed, 6 Dec 95 16:12:46 PST


>
>
> >> How would one create a cube with a repeated
> >> wallpaper paper texture on it? I though it'd be as simple
> >> as (the following VRML fragment):
> >>
> >> Texture2 { filename "wallpaper.gif" }
> >> Cube { }
>
> You cannot with Cube. Cube states that the entire texture goes on each face.
>

wow, we seem to have a knack for finding ambiguities in the spec these days.

the spec saith:

CUBE

This node represents a cuboid aligned with the coordinate axes. By default, the cube is centered at
(0,0,0) and measures 2 units in each dimension, from -1 to +1. The cube is transformed by the
current cumulative transformation and is drawn with the current material and texture.

If the current material binding is PER_PART, PER_PART_INDEXED, PER_FACE, or
PER_FACE_INDEXED, materials will be bound to the faces of the cube in this order: front (+Z),
back (-Z), left (-X), right (+X), top (+Y), and bottom (-Y).

Textures are applied individually to each face of the cube; the entire texture goes on each face. On
the front, back, right, and left sides of the cube, the texture is applied right side up. On the top, the
texture appears right side up when the top of the cube is tilted toward the camera. On the bottom,
the texture appears right side up when the top of the cube is tilted towards the -Z axis.

My esading:
it seems to me that this says "the entire texture" esferring
to the 0, to 1 coordinates of the texture.

thus scaling it would cause wallpapering (repeating).

I guess this means that the texture is not applied
in different pieces to the faces of the cube, but repeated
on each face.

----
Implicit, unanswered question:

what do the CLAMP and REPEAT values of the
wrapS and wrapT fields mean?


Cheers,
Adrian


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