[vtk-developers] OS X MultiSamples

David Gobbi david.gobbi at gmail.com
Tue Aug 6 17:23:12 EDT 2013


On Tue, Aug 6, 2013 at 2:09 PM, Sean McBride <sean at rogue-research.com> wrote:
> On Mon, 5 Aug 2013 16:41:22 -0600, David Gobbi said:
>>Sample buffers supported in OS X since 10.2.  Is this safe on all OS X
>>machines?  Is it possible that it could cause creation of the context
>>to fail if the gfx card does not support sample buffers?
>
> As I know next to nothing about OpenGL (VTK is my abstraction :)) I can't speak to this change really... but some thoughts:
>
> - any performance change?

Probably some, but none that I can perceive.  Multisamples have been
on by default on all other platforms (including Carbon) since at least
2007.  Only Cocoa was left out.  It can be turned off.

> - won't test output be slightly different, possibly requiring new baselines?

It's doubtful that new baselines will be needed. This has already been
dealt with for the other platforms, either by modifying the tests
(i.e. turning off multisampling where it made a difference) or by
uploading multiple regression images.

> - as it's a behaviour change, we should probably put this in release notes or somewhere

We can announce that antialiased rendering finally comes to VTK Cocoa,
just 7 years after it came to all other VTK platforms.

> - since those flags have been there since 10.2, I imagine any GPU supporting 10.5 or later (VTK 6's requirement) will support it
> - I can try this change locally, once I get my app working with VTK 6...

The change can easily be applied to a copy of the VTK 5 source, it's
just 4 lines.  I plan to test it with some of my software (which is
also based on VTK 5).  For rendering of wireframes it makes a huge
difference to the quality of the rendering.

 - David



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