[Qgis-developer] Discussion: could Ice be used in Qgis ?

[Matthias Kuhn]

Hi Julien,

On 07/24/2015 09:02 AM, Julien Michel wrote:
> Thank you all for you replies.
>
> 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).
>
> 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

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.
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?

Regards,
Matthias

> RAM or RAM to GPU transfert) whenever it is possible. I can maybe lend
> a hand in this perspective, if needed.
>
> Regards,
>
> Julien
>
> Le 22/07/2015 21:26, Tim Sutton a écrit :
>> Hi
>>
>>> On 22 Jul 2015, at 14:52, Paolo Cavallini <cavallini at faunalia.it
>>> <mailto:cavallini at faunalia.it>> wrote:
>>>
>>> Il 22/07/2015 11:48, Julien Michel ha scritto:
>>>> Hi Qgis developers,
>>>>
>>>> I wrote a small library called Ice which is able to render raster (and
>>>
>>> Hi all,
>>> I have seen ti in action during the recent FOSS4G, and I have been
>>> really impressed by its speed and capabilities. I think it would be a
>>> grat addition to QGIS, as either a main or alternative renderer.
>>
>> 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…
>>
>> Regards
>>
>> Tim
>>
>>
>>> All the best.
>>>
>>> -- 
>>> Paolo Cavallini - www.faunalia.eu <http://www.faunalia.eu>
>>> QGIS & PostGIS courses: http://www.faunalia.eu/training.html
>>> _______________________________________________
>>> Qgis-developer mailing list
>>> Qgis-developer at lists.osgeo.org <mailto:Qgis-developer at lists.osgeo.org>
>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>
>> —
>>
>>
>>
>>
>> Tim Sutton
>>
>> Visit http://kartoza.com to find out about open source:
>>
>> * Desktop GIS programming services
>> * Geospatial web development
>> * GIS Training
>> * Consulting Services
>>
>> Skype: timlinux Irc: timlinux on #qgis at freenode.net
>> <http://freenode.net>
>> Tim is a member of the QGIS Project Steering Committee
>>
>> Kartoza is a merger between Linfiniti and Afrispatial
>>
>
>
> -- 
> 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 
>
>
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