document perspective correction issues

diff --git a/docs/shading.html b/docs/shading.html
index 99342a329f77b438a8c9cb0d5f918730605b7935..0e1a5e1a7bcec5e639fc2bcdd59a980df976f2d2 100644 (file)
--- a/docs/shading.html
+++ b/docs/shading.html
@@ -46,6 +46,8 @@ in Mesa:
 <li>gl_ClipVertex
 <li>The derivative functions such as dFdx() are not implemented
 <li>The inverse trig functions asin(), acos(), and atan() are not implemented
+<li>The gl_Color and gl_SecondaryColor varying vars are interpolated
+    without perspective correction
 </ul>
 
 <p>