[Bug 31830] [bisected] broken shadows in Unigine Sanctuary and Lightsmark

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=31830

--- Comment #10 from Tom Stellard <tstellar at gmail.com> 2011-01-27 00:48:55 PST ---
(In reply to comment #3)
> What penumbra quality number are you using in Lightsmark? Are you seeing any
> error messages like this:
> 
> r300: ERROR: FS input generic 18 unassigned, not enough hardware slots.
> r300: ERROR: FS input generic 19 unassigned, not enough hardware slots.
> r300: ERROR: FS input generic 20 unassigned, not enough hardware slots.
> r300: ERROR: FS input WPOS unassigned, not enough hardware slots.
> 

In Lightsmark, I've been able to identify the failing shader and a few
instruction transformations that change the way the shadows are rendered.  I've
spent a lot of time looking at this, and all the transformations in question
appear to be correct.  It's possible that above errors are the reason why the
shadows are misrendering.  The last error about WPOS also appears in sanctuary. 

My hypothesis is that with these kinds of errors, the behavior of a shader is
undefined.  This means that prior to the commit in question, the scenes were by
luck being rendered correctly, or close enough so that it wasn't noticeable. 
Then, the modifications made to the shader by the reg_rename pass changed the
state of the GPU in such a way that the misrendering became more obvious.

Maybe Marek can comment on whether or not this is a plausible hypothesis.

-- 
Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.