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<base href="https://bugs.freedesktop.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - r600/sb: clobbers gl_Position -> gl_FragCoord"
href="https://bugs.freedesktop.org/show_bug.cgi?id=104143">104143</a>
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<th>Summary</th>
<td>r600/sb: clobbers gl_Position -> gl_FragCoord
</td>
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<th>Product</th>
<td>Mesa
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<th>Version</th>
<td>git
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<th>Hardware</th>
<td>x86-64 (AMD64)
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<th>OS</th>
<td>Linux (All)
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>Drivers/Gallium/r600
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
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<th>Reporter</th>
<td>gw.fossdev@gmail.com
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<th>QA Contact</th>
<td>dri-devel@lists.freedesktop.org
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</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=135998" name="attach_135998" title="piglit drawing output with sb enabled">attachment 135998</a> <a href="attachment.cgi?id=135998&action=edit" title="piglit drawing output with sb enabled">[details]</a></span>
piglit drawing output with sb enabled
With a variation of the piglit
spec/glsl-1.10/execution/variable-indexing/vs-output-array-vec2-index-wr
r600/sb clobbers the gl_Position/gl_FragCoord.
The variation consists in replacing two arrays of vec2 by one array of vec4 and
swizzling the elements to achieve the same result (by effectively interleaving
the two arrays).
A few observations:
* As can be seen from the colour coding screen shots, the array content is
correctly passed from the vertex shader to the fragment shader.
* The error only occurs for the uniform index value 0.
* When passing an additional parameter that contains a copy of gl_Position,
then this parameter seems to have the correct value (i.e. the vertex shader
correctly evaluates gl_Position).
* The byte code doesn't doesn't give any obvious indication why things go wrong
with the optimized shader.
My mesa is at fa8c1b92b7.
best,
Gert</pre>
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