Mesa (master): docs: document INTEL_PRECISE_TRIG envvar

[Juan Antonio Suárez Romero]

Module: Mesa
Branch: master
Commit: 883ca597df0debbf27431c218b2acb72986c52e2
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=883ca597df0debbf27431c218b2acb72986c52e2

Author: Juan A. Suarez Romero <jasuarez at igalia.com>
Date:   Wed Jan 11 18:51:35 2017 +0100

docs: document INTEL_PRECISE_TRIG envvar

v2: use more generic description (Jordan)

Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

---

 docs/envvars.html | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/docs/envvars.html b/docs/envvars.html
index 9eee8db..276cea3 100644
--- a/docs/envvars.html
+++ b/docs/envvars.html
@@ -187,6 +187,8 @@ See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
    <li>do32 - generate compute shader SIMD32 programs even if workgroup size doesn't exceed the SIMD16 limit</li>
    <li>norbc - disable single sampled render buffer compression</li>
 </ul>
+<li>INTEL_PRECISE_TRIG - if set to 1, true or yes, then the driver prefers
+   accuracy over performance in trig functions.</li>
 </ul>