[sldev] [SNOW] Problems with high resolution textures

[Gordon Wendt]

There's also a really popular misfiled (at vwr instead of snow) at
http://jira.secondlife.com/browse/VWR-14180 that's about this problem just
an fyi.

-Gordon

On Sun, Jun 21, 2009 at 1:04 AM, Sheet Spotter <sheet.spotter at gmail.com>wrote:

>  An enhancement in the Snowglobe viewer may be responsible for problems
> with high resolution textures. I’m hoping someone in SLDev can confirm this
> and start the search for solutions.
>
>
>
> Two examples of this problem are SNOW-45 (some large textures do not render
> properly) and SNOW-48 (textures not resolving on megaprims).
>
>
>
> The Texture Console provided a clue to the underlying cause. In SNOW-45 and
> SNOW-48 when you zoom in on the objects the “Area” column in the Texture
> Console seems to be artificially limited to 4,096 or 65,536 for the
> misbehaving textures. (You need to right-click and edit the object to see
> its textures highlighted in the Texture Console.) In some cases the Area
> value actually drops when you zoom in.
>
>
>
> The new Snowglobe viewer includes optimizations that reduce the detail in
> textures that are “not important to the camera”. This seems to be aimed at
> improving memory utilization by limiting the use of large textures when they
> have no benefit. For example, when a face is “less important” it will be
> drawn with only a 64x64 texture (that’s where the 4,096 comes from). Larger
> faces that are less important may be drawn with a 256x256 texture (that’s
> the 65,536 value).
>
>
>
> In the Snowglobe source code the LLFace::calcImportanceToCamera method
> determines how important each face is in the avatar’s camera, and the
> LLFace::getTextureVirtualSize method imposes limits on the texture size
> based on this importance. (The value returned by getTextureVirtualSize is
> displayed in the Area column in the Texture console.) One of these two
> methods seems to be responsible for limiting the detail in the textures
> displayed in SNOW-45 and SNOW-48.
>
>
>
> I hope someone more experienced in this area of the code can confirm these
> findings, and further the cause by proposing possible solutions. A simpler
> explanation of these findings will be added as a comment to SNOW-48.
>
>
>
>
>
> Sheet Spotter
>
>
>
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