mesa: Changes to 'master'
Eric Anholt
anholt at kemper.freedesktop.org
Wed Feb 6 15:44:36 PST 2008
src/mesa/drivers/dri/i915/i915_fragprog.c | 228 +++++++++++++++++++-----------
1 file changed, 151 insertions(+), 77 deletions(-)
commit diffs at http://gitweb.freedesktop.org/?p=mesa/mesa.git;a=summary
New commits:
commit 700a77fb48f364f85e013cf5fb68c04eb83317e7
Author: Eric Anholt <eric at anholt.net>
Date: Wed Feb 6 15:41:04 2008 -0800
[915] Fix COS function using same plan as SIN.
The previous COS function failed badly outside of [-pi/2, pi/2].
commit 2551a5ee80ab523006618c79766e2409b2a62d84
Author: Eric Anholt <eric at anholt.net>
Date: Wed Feb 6 15:38:16 2008 -0800
[915] Use a quartic term to improve the accuracy of SIN results.
This is described in the link in the comment, and is the same technique that
r300 uses.
commit d98abcbef0bd4200fc0fd30fc0524bf452df3572
Author: Eric Anholt <eric at anholt.net>
Date: Wed Feb 6 11:34:14 2008 -0800
[915] Fix fp SIN function, and use a quadratic approximation instead of Taylor.
The Taylor series notably fails at producing sin(pi) == 0, which leads to
discontinuity every 2*pi. The quadratic gets us sin(pi) == 0 behavior, at the
expense of going from 2.4% THD with working Taylor series to 3.8% THD (easily
seen on comparative graphs of the two). However, our previous implementation
was producing sin(pi) < -1 and worse, so any reasonable approximation is an
improvement. This also fixes the repeating behavior, where the previous
implementation would repeat sin(x) for x>pi as sin(x % pi) and the opposite
for x < -pi.
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