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<body><span class="vcard"><a class="email" href="mailto:apuentes@igalia.com" title="Antia Puentes <apuentes@igalia.com>"> <span class="fn">Antia Puentes</span></a>
</span> changed
<a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - gl_BaseVertex should always be zero when the draw command has no <basevertex> parameter"
href="https://bugs.freedesktop.org/show_bug.cgi?id=102678">bug 102678</a>
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<th>What</th>
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<th>Added</th>
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<td style="text-align:right;">CC</td>
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<td>apuentes@igalia.com, idr@freedesktop.org, kenneth@whitecape.org
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<b><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - gl_BaseVertex should always be zero when the draw command has no <basevertex> parameter"
href="https://bugs.freedesktop.org/show_bug.cgi?id=102678#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED - gl_BaseVertex should always be zero when the draw command has no <basevertex> parameter"
href="https://bugs.freedesktop.org/show_bug.cgi?id=102678">bug 102678</a>
from <span class="vcard"><a class="email" href="mailto:apuentes@igalia.com" title="Antia Puentes <apuentes@igalia.com>"> <span class="fn">Antia Puentes</span></a>
</span></b>
<pre>(In reply to Antia Puentes from <a href="show_bug.cgi?id=102678#c2">comment #2</a>)
<span class="quote">> (In reply to Kenneth Graunke from <a href="show_bug.cgi?id=102678#c1">comment #1</a>)
> > I believe Antia is working on a fix.
>
> I have a patch that fixes the tests. I am currently testing for regressions,
> if there isn't any I will send it shortly.</span >
The patch produced regressions related to gl_VertexID. Specifically in the
tests which involve gl*DrawArrays*, pass a value different from zero as
argument of the <first> parameter of the draw command, and check if gl_VertexID
is correct.
According to the spec, for non-indexed draw calls: "The vertex ID of the ith
element transferred is <first> + i."
Mesa's compiler lowers the gl_VertexID as gl_VertexID(base zero) +
gl_BaseVertex, which is the way expected for indexed draw calls. For
non-indexed draw calls, this currently works because we use the <first>
argument as gl_BaseVertex. If we give gl_BaseVertex a zero value for
gl*DrawArrays* as the spec says, the gl_VertexID will be incorrect.
Not sure how to fix the gl_VertexID issue, it looks like the i965 does not have
a way to add a base value during the vertex-id generation.</pre>
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