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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 - invariant qualifier is not valid for shader inputs"
href="https://bugs.freedesktop.org/show_bug.cgi?id=96971">96971</a>
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<th>Summary</th>
<td>invariant qualifier is not valid for shader inputs
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>git
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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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/DRI/i965
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<th>Assignee</th>
<td>idr@freedesktop.org
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<th>Reporter</th>
<td>qiankun.miao@intel.com
</td>
</tr>
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<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
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<p>
<div>
<pre>Currently, only glsl es in mesa follows this rule. But glsl compiler should
also follow this rule. The behavior is specified in GLSLangSpec.4.40, in
Section 4.8.1 The Invariant Qualifier: "Only variables output from a shader can
be candidates for invariance." and "As only outputs need be declared with
invariant, an output from one shader stage will still match an input of a
subsequent stage without the input being declared as invariant."
So, input without invariant declaration should be valid.
But following code snippet in mesa/src/compiler/glsl/link_varyings.cpp makes it
an error:
if (!prog->IsES && input->data.invariant != output->data.invariant) {
linker_error(prog,
"%s shader output `%s' %s invariant qualifier, "
"but %s shader input %s invariant qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
(output->data.invariant) ? "has" : "lacks",
_mesa_shader_stage_to_string(consumer_stage),
(input->data.invariant) ? "has" : "lacks");
return;
}</pre>
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