On 06/04/2012 01:31 PM, Olivier Galibert wrote:
On Mon, Jun 04, 2012 at 01:11:13PM -0700, Ian Romanick wrote:
From: Ian Romanick<ian.d.roman...@intel.com>
In single precision, 1.5707963 becomes 1.5707962513 which is too
small. However, 1.5707964 becomes 1.5707963705 which is just right.
The value 1.5707964 is already used in asin.ir.
NOTE: This is a candidate for stable release branches.
If piglit stops bitching on that partical problem thanks to such a
small change, it's just beautiful.
It does fix the acos issue in piglit. The closed-source test suite that
we use still isn't happy, but I think that just means we need better
approximations for acos and asin.
asin(vec4(.2, .6, .8, 1.)) has an absolute error of (0.0000105351
0.0001987219 0.0001262426 0.0000003576). The results for .6 and .8 are
especially bad, but even the .2 result should be better. The
closed-source test suite wants an absolute error of 1e-5 for asin and acos.
Do we need a better precision atan, or should piglit just be told to
shutup? The shutup patch has been sent it ages ago, but I can't do
the "more precision" one if that's what's wanted.
I think we need a better atan. The result that it produces is not very
good. I plan to look into that more tonight.
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
