strange artifacts, could this be a bug?

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Kai Kostack
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Joined: Tue Feb 07, 2006 5:24 pm

strange artifacts, could this be a bug?

Post by Kai Kostack »

here is a part of the image which is produced by the internal renderer from a recent SVN build:

Image

you'll notice all the black pixel groups. i first thought of a simple raydepth problem but after testing around a bit it looks like something different to me. i have disabled AO and all lights and the problem persists. i found the fact interesting that there are no single black pixels but they only occure in groups of 4.

any idea to prevent this? i tried a build from september and there i couldn't see black spots like this.

edit:
blender shows as color value of those pixels "1.#QO" or "-1.#IO", the zbuffer seems to be correct. maybe this helps.

stiv
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Joined: Tue Aug 05, 2003 7:58 am
Location: 45N 86W

Post by stiv »

We get reports of weird artifacts from 'optimized' builds. If you are using compiler flags like -O3 and -ffastmath, try backing them off.

Kai Kostack
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Joined: Tue Feb 07, 2006 5:24 pm

Post by Kai Kostack »

thank you for the quick reply.

i checked my settings and could only find the -O2 switch and no more optimizations. then i have tried -O1 and now everything works.

looks like the most builds out there are built with -O2 because none of those i tried worked correct.

anyway, it works now. thanks. :)

stiv
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Joined: Tue Aug 05, 2003 7:58 am
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Post by stiv »

Interesting. -O2 is usually considered to be safe optimization; basically trading size for speed.

/me wonders if it is time to clean up warning msgs again so the poor compiler is not confused.

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