Originally Posted by boat_alexandra
Basically there are three possible options:
1) no compression
-- maybe fastest for initial results, but uses by far the most memory
-- maybe slower initial results, uses little graphics memory (you must have expert mode enabled for this option)
3) compression with caching -- maybe even slower initial results, but uses the least memory, and gives good performance once the cache is built. It also uses about as much disk space as the normal chart file.
Just to be totally clear: these 3 options only apply when OpenGL is enabled, right?
I'm sorry for being so short yesterday, but I did spend several hours testing this.
Having spent a little time testing again today, I can confirm that on my compy raster charts
are faster with OpenGL disabled than they are with OpenGL ticked but "Texture Compression with Caching" unticked (in the basic options).
To test OpenCPN
and become familiar with it, I started by loading all the NOAA charts
into it (RNC + ENC
, about 7.5GB), some Dutch vector ones, and the New Zealand
raster collection (which covers the whole of the Pacific).
With OpenGL disabled, I can zoom in and out perfectly smoothly, using raster charts all the way down to the 1:25,000 charts of the US west coast
(e.g. Roche Harbor, NOAA chart 18433), out to the 1:10,000,000 chart (NOAA chart 50), then zoom back into the Hawaii
islands (e.g 1:5000 NOAA 19341) and it is perfectly smooth.
Switching back and forth between the two settings has led to confusion sometimes - at least twice I have experienced spinning beachballs and thought "this isn't right, I thought the non-openGL performance was better than this", only to find that I had accidentally enabled OpenGL. It is indeed the OpenGL ("Texture Compression with Caching" unticked) that is slower.
I will enable the OpenGL advanced-advanced options and try to spend some time with it the next couple of days.
Initial impressions are that OpenGL + "Texture Compression with Caching" is not as fast as OpenGL disabled, on my system.
I tried to prerender by enabling OpenGL and starting OpenCPN
with the -rebuild_gl_raster_cache flag, but the number of maps I have loaded (you probably think excessively many) make it a 17 hour job. I had to leave it running overnight, and 4.0.0 seems to keep crashing at a certain point (when the raster_texture_cache directory is about 10GB or 11GB in size (NB: that's about twice the size of the original .KAP files)). I have just installed 4.1.602 and am now heating
Not sure what you mean by "DC-mode" - with OpenGL disabled? I guess if you're sceptical that non-GL rendering is adequate, then I'd understand that, but really it's perfectly fast and totally usable.
You mention course-up mode - I'm sitting at home on my laptop
with North-up, but where the maps are skewed with north at a funny
angle on the page, that doesn't take long to paint
, at all. Get the Golden Gate Bridge in the middle of the screen
, quilting off, and switch between charts 18652 and 18645. On my Mac the charts switch, rotated, just as fast as you click them. I think chart 18652 (big PDF
) has the bridge at two scales at two different angles, so that's three angles OpenCPN is switching between instantly.
In fact that big PDF is overloads the Preview.app PDF viewer, and spinning beachballs make it unusable (maybe if I had more patience), whereas viewing the same area in OpenCPN (with OpenGL disabled) is fine.
Underzoomed - well, it's too fine to see detail, but I wouldn't call it "ugly".
I'm halfway tempted to do a screencast for you guys, so you can see I'm not bullshitting you about the Mac's non-GL performance, and to make sure we're not talking at any cross purposes.