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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 - interpolateAtSample check for input parameter is too strict"
href="https://bugs.freedesktop.org/show_bug.cgi?id=101378">101378</a>
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<th>Summary</th>
<td>interpolateAtSample check for input parameter is too strict
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>17.0
</td>
</tr>
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<th>Hardware</th>
<td>x86-64 (AMD64)
</td>
</tr>
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<th>OS</th>
<td>Linux (All)
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>glsl-compiler
</td>
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<th>Assignee</th>
<td>mesa-dev@lists.freedesktop.org
</td>
</tr>
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<th>Reporter</th>
<td>freedesktop@ca.sh13.net
</td>
</tr>
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<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
</td>
</tr></table>
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<pre>The following code snippet fails on Mesa 17.0.3 with the following error:
in GeometryToPixel
{
vec3 color;
vec2 uv;
} gs2ps;
out vec4 Color;
void main ()
{
Color = vec4(gs2ps.color, 1);
if (length(interpolateAtSample(gs2ps.uv, gl_SampleID))>1) {
discard;
}
}
This is the error:
0:10(1): error: if a fragment input is (or contains) an integer, then it
must be qualified with 'flat'
0:10(8): error: `gl_SampleID' redeclared
0:18(33): error: parameter `interpolant` must be a shader input
0:18(6): error: no matching function for call to `length(error)';
candidates are:
0:18(6): error: float length(float)
0:18(6): error: float length(vec2)
0:18(6): error: float length(vec3)
0:18(6): error: float length(vec4)
0:18(6): error: double length(double)
0:18(6): error: double length(dvec2)
0:18(6): error: double length(dvec3)
0:18(6): error: double length(dvec4)
0:18(6): error: operands to relational operators must be scalar and numeric
0:18(6): error: if-statement condition must be scalar boolean
Changing the shader to use:
in vec3 icolor;
in vec2 iuv;
fixes the problem. This seems to be related to
<a href="https://patchwork.freedesktop.org/patch/15298/">https://patchwork.freedesktop.org/patch/15298/</a>, but the input variable check is
too strict. It should work with an input block as well, which is for instance
used by the G-Truc samples:
<a href="https://github.com/g-truc/ogl-samples/blob/655559499c23b9566ac432cc2af33cde6646271c/data/gl-400/fbo-multisample-interpolate.frag">https://github.com/g-truc/ogl-samples/blob/655559499c23b9566ac432cc2af33cde6646271c/data/gl-400/fbo-multisample-interpolate.frag</a>
Code in question works fine on AMD desktop drivers.</pre>
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