<html>
<head>
<base href="https://bugs.freedesktop.org/" />
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Derivatives of gl_Color wrong when helper pixels used"
href="https://bugs.freedesktop.org/show_bug.cgi?id=95130">95130</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Derivatives of gl_Color wrong when helper pixels used
</td>
</tr>
<tr>
<th>Product</th>
<td>Mesa
</td>
</tr>
<tr>
<th>Version</th>
<td>git
</td>
</tr>
<tr>
<th>Hardware</th>
<td>Other
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Component</th>
<td>Drivers/Gallium/radeonsi
</td>
</tr>
<tr>
<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jlegg@feralinteractive.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=123239" name="attach_123239" title="Test program">attachment 123239</a> <a href="attachment.cgi?id=123239&action=edit" title="Test program">[details]</a></span>
Test program
Along the edges of triangles and around where fragments are rejected due to
depth testing, the GLSL functions dFdx, dFdy, and fwidth return incorrect
values when the argument is dependant on gl_Color or gl_SecondaryColor.
I've attached a program reproducing the issue. It takes derivatives of a
constant, which should be 0. It is expected to produce a black window. However,
the edges of the triangle it draws are visible because of this bug.
The error does not occur when environment variable LIBGL_ALWAYS_SOFTWARE is set
to 1.
I'm using Mesa git 0831eb9 with an AMD R9 270 on x86_64 Fedora 22.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the assignee for the bug.</li>
</ul>
</body>
</html>