[Mesa-dev] Project ideas [was Re: Gallium3D and Glide]

[Ian Romanick]

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On 03/01/2011 05:36 AM, Keith Whitwell wrote:

> Create an automated bug-finder for gallium drivers.  
> 
> Step one: create a "split and compare" gallium driver (perhaps based on
> failover) which runs the same set of commands on two different gallium
> drivers (eg softpipe and r600g).  At each frame, compare the two images
> and see if there are differences.

For non-trivial rendering, that had better be an awful fuzzy "compare."
 All of the 3D rendering specs allow a large amount of variation in
rasterization rules and precision rules.  Have you ever looked at
OpenGL's line drawing rules?  Line locations can vary by +/- a pixel in
any direction.

That's not to say this isn't interesting, but it's probably only
interesting for comparing the results of different drivers for the same
hardware (e.g., r600g with and without some change).

> Step two: as above, but save the command stream each frame so that you
> can bisect into it to find the actual draw call which caused the
> failure.

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