OpenGL Canvas or Not

[Boudewijn Rempt]

On Fri, 18 Oct 2013, Enrico Guarnieri wrote:

> 1st Problem:
> After removing the texture buffer option in Git the opengl canvas became very slow and now it's unusable.

Ah, bah... I only got reports of Krita breaking for people because of that 
option. I can revert it, of course. The problem remains that I haven't got 
a representative set of test hardware, no nvidia, no radeon, so I only 
test on Intel GPUs's

> 
> My configuration:
> 
> Processor    4x Intel(R) Core(TM) i5 CPU 650 @ 3.20GHz
> Memory    8GB
> Operating System    Ubuntu 12.04.3 LTS
> 
> Display Resolution    1680x1050 pixels
> OpenGL Renderer      GeForce 9500 GT/PCIe/SSE2
> Graphic Card memory 1024MB
> NVIDIA Driver Version 319.32
> 
> (Tried with older nvidia cards and a radeon hd 4670 too but with the same result.)
> 
> 
> Kernel    Linux 3.2.0-54-generic (x86_64) Ubuntu SMP
> Default C Compiler    GNU C Compiler version 4.6.3
> 
> (Tried with the lts-raring stack too but with the same result.)
> 
> Desktop Environment tested  Xfce4/Kde4/Gnome3 with/without compositing active.
> 
> 
> 2nd problem:
> Why the software mode is so slow in rotating and zooming the viewport? In other painting programs is very fast without gpu acceleration using a single core too!

I don't find it particularly slow, even in software mode, but that might 
depend on a lot of things, including the size of your image, the load of 
your system and a lot more. But as far as I'm concerned, I consider the 
software-mode canvas 'done', and I want to focus on getting the opengl 
canvas running well for everyone.

> 3rd Problem:
> Why the painting in the viewport is "blurry" in opengl canvas and in software mode as well? For example Gimp have a very sharp and precise rendering...

OpenGL: because opengl only offers linear (bi or tri, with tri being more 
blurry) scaling modes. We're working on adding bicubic scaling to opengl 
mode, but that's very tricky.

See: https://bugs.kde.org/show_bug.cgi?id=313502

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