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Hi Julien,<br>
<br>
<div class="moz-cite-prefix">On 07/24/2015 09:02 AM, Julien Michel
wrote:<br>
</div>
<blockquote cite="mid:55B1E305.4090601@cnes.fr" type="cite">
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<div class="moz-cite-prefix">Thank you all for you replies.<br>
<br>
Well I agree with all the comments made here : ice lacks a whole
lot of things to replace Qgis rendering, and switching the
rendering backend might be a very complex and time consuming
task (that is almost the 1st thing I told Paolo). Moreover, Ice
focuses on being efficient for rendering : that means a whole
bunch or things are locked within Ice code (for instance, Ice
takes care of reading data from the hard drive).<br>
<br>
Still, if you are getting into pure OpenGl rendering someday,
and looking for responsive features, Ice can be a good source of
inspiration. it's not rocket science, just a few things to keep
in mind (in addition to tile caching and multi-resolution) : let
the GPU take care of everything it can, including all contrast
changes and reprojection, and avoid heavy operations (like HDD
to </div>
</blockquote>
<br>
Thank you for the hints. Please allow me one question here. I have
recently plaied with OpenGL for rendering and did let the GPU do CRS
transformation. I could not get it to work to my full satisfaction,
based on the fact that I only had float but no double precision.
Therefore e.g. CRS 21781 (in meters) already uses 6 figures for
meters, one more is still ok but when you zoom into cm resolution
you start to see the precision / rounding errors in rendering.<br>
For reprojection I guess you had to also deal with precision of
coordinates. Did you use OpenGL features which are able to use
double, transform coordinates into an intermediate format before
sending them to the GPU or something totally different?<br>
<br>
Regards,<br>
Matthias<br>
<br>
<blockquote cite="mid:55B1E305.4090601@cnes.fr" type="cite">
<div class="moz-cite-prefix">RAM or RAM to GPU transfert) whenever
it is possible. I can maybe lend a hand in this perspective, if
needed.<br>
<br>
Regards,<br>
<br>
Julien<br>
<br>
Le 22/07/2015 21:26, Tim Sutton a écrit :<br>
</div>
<blockquote
cite="mid:F9645A26-8BBF-4921-ADD4-F1D3B6305214@kartoza.com"
type="cite">
<meta http-equiv="Context-Type" content="text/html; ">
Hi
<div class=""><br class="">
<blockquote type="cite" class="">On 22 Jul 2015, at 14:52,
Paolo Cavallini <<a moz-do-not-send="true"
href="mailto:cavallini@faunalia.it" class="">cavallini@faunalia.it</a>>
wrote:<br class="">
<br class="">
Il 22/07/2015 11:48, Julien Michel ha scritto:<br class="">
<blockquote type="cite" class="">Hi Qgis developers,<br
class="">
<br class="">
I wrote a small library called Ice which is able to render
raster (and<br class="">
</blockquote>
<br class="">
Hi all,<br class="">
I have seen ti in action during the recent FOSS4G, and I
have been<br class="">
really impressed by its speed and capabilities. I think it
would be a<br class="">
grat addition to QGIS, as either a main or alternative
renderer.<br class="">
</blockquote>
<div class=""><br class="">
</div>
<div class="">As nice as the idea is, I think it will be quite
a massive undertaking and we would break all the beautiful
(ok and ugly) cartography that people have come up with
using the rich array of rendering styles that QGIS currently
has. I would also like to see a native OpenGL renderer one
day so that we can start to thing about native 3D support.
Maybe it would be nice to make a patch that lets you swap
between Qt rendering backend and Ice, but honestly its
probably a lot of work and may just fade away like the old
mapnick renderer did…</div>
<div class=""><br class="">
</div>
<div class="">Regards</div>
<div class=""><br class="">
</div>
<div class="">Tim</div>
<div class=""><br class="">
</div>
<br class="">
<blockquote type="cite" class="">All the best.<br class="">
<br class="">
-- <br class="">
Paolo Cavallini - <a moz-do-not-send="true"
href="http://www.faunalia.eu" class="">www.faunalia.eu</a><br
class="">
QGIS & PostGIS courses: <a moz-do-not-send="true"
href="http://www.faunalia.eu/training.html" class="">http://www.faunalia.eu/training.html</a><br
class="">
_______________________________________________<br class="">
Qgis-developer mailing list<br class="">
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href="mailto:Qgis-developer@lists.osgeo.org" class="">Qgis-developer@lists.osgeo.org</a><br
class="">
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href="http://lists.osgeo.org/mailman/listinfo/qgis-developer">http://lists.osgeo.org/mailman/listinfo/qgis-developer</a><br
class="">
</blockquote>
<br class="">
<div class=""><span>—</span><br class="">
<span><br class="">
</span><span><br class="Apple-interchange-newline">
<span><img id="3CABBD9A-0665-409C-A129-DEF4D232F5CC"
src="cid:part6.09080705.02040009@opengis.ch" class=""
height="66" width="160"></span>
<div class=""><br class="Apple-interchange-newline">
<br class="">
</div>
<div class="">Tim Sutton</div>
<div class=""><br class="">
</div>
<div class="">
<div class="">Visit <a moz-do-not-send="true"
href="http://kartoza.com" class="">http://kartoza.com</a> to
find out about open source:</div>
<div class=""><br class="">
</div>
<div class="">
<div class="">* Desktop GIS programming services</div>
<div class="">* Geospatial web development</div>
<div class="">* GIS Training</div>
<div class="">* Consulting Services</div>
<div class=""><br class="">
</div>
<div class="">
<div class="">Skype: timlinux Irc: timlinux on #qgis
at <a moz-do-not-send="true"
href="http://freenode.net" class="">freenode.net</a></div>
<div class="">Tim is a member of the QGIS Project
Steering Committee</div>
<div class=""><br class="">
</div>
<div class="">Kartoza is a merger between Linfiniti
and Afrispatial</div>
</div>
</div>
</div>
</span></div>
<br class="">
</div>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Julien MICHEL
CNES - DCT/SI/AP - BPI 1219
18, avenue Edouard Belin
31401 Toulouse Cedex 09 - France
Tel: +33 561 282 894 - Fax: +33 561 283 109 </pre>
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