Re: Texture mip streaming prioritization

--===============2650254915106648969==
Content-Type: multipart/alternative; boundary=001a11c218ae1dc38d04e21fe50d

--001a11c218ae1dc38d04e21fe50d
Content-Type: text/plain; charset=ISO-8859-1

On Mon, Jul 22, 2013 at 12:16 AM, Josh Green <[email protected]> wrote:

> Hi There,
>
> I'm currently working on a texture streaming system and looking into ways
> to prioritize which mips on which textures should be loaded.
> I was hoping that people on this list may have experience with these
> algorithms that they could share?
>
> Currently I know which mips need to be loaded in order to render a scene
> without degradation in image quality.
> I would now like to apply a memory budget to textures, and make decisions
> about which mips of which textures should be loaded over others.
>
> My current line of thinking involves comparing cost / benefit of loading
> each individual mip.
> i.e.
>
> How many pixels would be affected by a particular mip level being loaded
> versus how much memory would that mip level use?
>
> This becomes Priority = Benefit / Cost
>
> I'd then sort for highest priority and assign memory budget to those mips
> at the top of the list.
>
> Any thoughts? comments? Alternatives that work better? Alternatives that
> have worked enough?
>

I would bake in some kind of factor that relates to "quality improvement"
as well. If you have a 4k eye ball texture and it's currently at MIP 2
(1Kx1K), it probably won't gain much from loading another MIP even if it's
covering a lot of pixels. So you need to compute how far off the pixel
currently is from the *ideal* MIP level, and improve pixels that are far
off first (weighted by pixel count).


Assuming you only load one MIP level at a time (i.e. if MIP N is currently
loaded, you'll only consider N-1), maybe something like:

(desired_mip - current_mip) * num_pixels / memory_usage, add tuning knobs
as needed...

That first factor relates to how far "off" a pixel currently is from its
ideal MIP level, i.e. how much in need of improvement those pixels are.

-- 
Sebastian Sylvan

--001a11c218ae1dc38d04e21fe50d
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quo=
te">On Mon, Jul 22, 2013 at 12:16 AM, Josh Green <span dir=3D"ltr">&lt;<a h=
ref=3D"mailto:[email protected]" target=3D"_blank">[email protected]</a>&gt=
;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;padding=
-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-l=
eft-style:solid"><div dir=3D"ltr">Hi There,<br><br>I&#39;m currently workin=
g on a texture streaming system and looking into ways to prioritize which m=
ips on which textures should be loaded.<div>
I was hoping that people on this list may have experience with these algori=
thms that they could share?<br>
<br>Currently I know which mips need to be loaded in order to render a scen=
e without degradation in image quality.<br>I would now like to apply a memo=
ry budget to textures, and make decisions about which mips of which texture=
s should be loaded over others.=A0<br>

<br>My current line of thinking involves comparing cost / benefit of loadin=
g each individual mip.<br>i.e.<br><br>How many pixels would be affected by =
a particular mip level being loaded versus how much memory would that mip l=
evel use?<br>

<br>This becomes Priority =3D Benefit / Cost<br><br>I&#39;d then sort for h=
ighest priority and assign memory budget to those mips at the top of the li=
st.<br><br>Any thoughts? comments? Alternatives that work better? Alternati=
ves that have worked enough?<br clear=3D"all">
</div></div></blockquote><div>=A0</div><div>I would bake in some kind of fa=
ctor that relates to &quot;quality improvement&quot; as well. If you have a=
 4k eye ball texture and it&#39;s currently at MIP 2 (1Kx1K), it probably w=
on&#39;t gain much from loading another MIP even if it&#39;s covering a lot=
 of pixels. So you need to compute how far off the pixel currently is from =
the <em>ideal</em> MIP level, and improve pixels that are far off=A0first (=
weighted by pixel count).</div>
<div>=A0</div><div>=A0</div><div>Assuming you only load one MIP level at a =
time (i.e. if MIP N is currently loaded, you&#39;ll only consider N-1), may=
be something like:</div><div>=A0</div><div>(desired_mip - current_mip) * nu=
m_pixels=A0/ memory_usage, add tuning knobs as needed... </div>
<div>=A0</div><div>That first factor relates to how far &quot;off&quot; a p=
ixel currently is from its ideal MIP level, i.e. how much in need of improv=
ement those pixels are.</div><div><br>-- <br>Sebastian Sylvan
</div></div></div></div>

--001a11c218ae1dc38d04e21fe50d--


--===============2650254915106648969==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

------------------------------------------------------------------------------
See everything from the browser to the database with AppDynamics
Get end-to-end visibility with application monitoring from AppDynamics
Isolate bottlenecks and diagnose root cause in seconds.
Start your free trial of AppDynamics Pro today!
http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk
--===============2650254915106648969==
Content-Type: text/plain; charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
GDAlgorithms-list mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
Archives:
http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
--===============2650254915106648969==--