.png render problem with SVN

Is anyone else getting weird .png’s when saving renders made with recent SVN builds?

The default cube saves like this:-


It looks fine in the render window, and I can save all the other formats that I tested - .tif, .exr, .jpg, .tga and the official release saves normally.
If I save it as a .png with RGBA enabled it saves normally except with no background colour. So it’s no big deal, but I guess someone might want to know.

I never had that problem, what date was the SVN build made.

It works fine in revision 16274.

I use that to save a decal with no background, so it works transparently with a base image.
(Translucency effects are nice with it too.)

It is still with me on Rev. 16297 built today on 64 bit Ubuntu 8.04, but seems to be only .png’s saved without an alpha channel.

If you’re doing any optimisations during building, turn them off and try again.


Yep. Seems it was this one:- REL_CFLAGS = [ ‘-O3’,’-pipe’ ]

Commented out it saves like it should.

Thanks again.

O2 is the highest optimisation you should ever do in Blender, higher and more aggressive forms of optimisation (like fast-math et al) will introduce errors in calculations. In renders it manifests often as artifacts, like black or white spots. For that very reason, the official builds we make don’t have optimisation turned on.


Thanks jesterKing, saved the day again.
I read about -fast-math maybe not being useful, but I thought ‘-03’ was stable.

It doesn’t occur if I build with ‘-02’, so I’ll settle for that. To be honest optimising on linux doesn’t reduce render times by much; maybe 10%.

Some people just want that 10% too, I guess. :ba:


Ironically enough, the Ubuntu repository version is even faster, and beats anything I can build.