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<th>Priority</th>
<td>medium
</td>
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<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Front/Backfaces do not cover the same pixels when rasterized"
href="https://bugs.freedesktop.org/show_bug.cgi?id=78914">78914</a>
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<th>Assignee</th>
<td>mesa-dev@lists.freedesktop.org
</td>
</tr>
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<th>Summary</th>
<td>Front/Backfaces do not cover the same pixels when rasterized
</td>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Reporter</th>
<td>florianlink@gmail.com
</td>
</tr>
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<th>Hardware</th>
<td>Other
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Version</th>
<td>10.1
</td>
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<th>Component</th>
<td>Mesa core
</td>
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<th>Product</th>
<td>Mesa
</td>
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<pre>When trying to run my GLSL raycaster with Mesa/llvmpipe, I recognized artifacts
due to the wrong ray start/end positions. I render the start/end rays as boxes
where the front face is the start position and the back face is the back
position. The problem seems to be that the front/back faces do not cover the
exact same pixels in the framebuffer, even when they share the same edges.
On NVidia/ATI cards with native driver, the back faces cover the same pixels as
the front faces.
This can be reproduced by rendering a triangle with culling turned off and
blending turned on. When rotating the triangle one can see the artifacts on the
borders of the triangle.</pre>
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</p>
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