| Re: [platform-dev] most performant way to paint a (platform-specific) pixel-array |
_______________________________________________For OpenGL stuff, you want to avoid Image / ImageData and keep as much of the rendering in OpenGL as possible, running on the graphics card. Copying memory between GPU and main memory (Java heap) will be slow.
SWT has bindings to some OpenGL libraries, but I don’t think they’ve been updated in quite a while. Have a look though: https://www.eclipse.org/swt/opengl/
Best, NickOn Apr 20, 2021, 2:15 PM -0400, Christoph Läubrich <laeubi@xxxxxxxxxxxxxx>, wrote:
Hi Nick,
currently I don't have any measures and just trying to collect some
information. My use case is to integrate a software OpenGL render (jGL)
and for that I need to store the rendered pixels somewhere and of course
later I need to paint them.
I just wondering if I could short-circuit some of the steps
(imagedata>image>gc) and maybe write directly inside some kind of
direct-buffer.
For example if I look at
org.eclipse.swt.graphics.Image.init(ImageData) for GTK there seem to
happen some more action than simply keeping a reference to the image
data, e.g. a scale factor is computed, copy of data is involved, color
transformation and so on are performed.
Maybe as you mention it does not matter, on the other hand the faster
the better here (maybe) this also is a bit depending on the effort to
make this happen here of course but I'd like to investigate a bit if I
should take some internals into account before starting to implement the
actual thing.
Am 20.04.21 um 19:19 schrieb Nick Edgar:
Hi Christoph,_______________________________________________
That approach is generally the recommended way to paint images
<https://www.eclipse.org/articles/Article-SWT-images/graphics-resources.html> in
SWT. Painting of a pre-created Image should be as fast as the OS allows.
Have you measured the times involved? Which phase do you need to speed up:
1. creating ImageData,
2. creating Image from ImageData, or
3. painting Image?
If 1, see if you can directly manipulate the ImageData’s data, or using
setPixels
<https://github.com/eclipse/eclipse.platform.swt/blob/eae1f39bbc4fdd01ac0416927ed3fa2d50ec9a9f/bundles/org.eclipse.swt/Eclipse%20SWT/common/org/eclipse/swt/graphics/ImageData.java#L1307>.
If 2, check which image format you’re using — it may not map directly to
the native display, and thus be expensive to convert.
If 3, I’d be surprised, but it would be good to know details and the
times for 1,2,3.
Best, Nick
On Apr 19, 2021, 5:20 AM -0400, Christoph Läubrich
<laeubi@xxxxxxxxxxxxxx>, wrote:
I have a pixel-buffer and like it o be painted in the most performant
way onto a SWT Canvas.
Current approach is to convert this into an ImageData, create an image
and then paint it inside PaintListener to the GC.
Is there a way to avoid this intermediate steps? I won't mind if I need
to provide platform-specific implementations if it is possible to gain
performance here.
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