[Bug 71741] New: GL_ARB_ES3_compatibility and std140 arrays

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=71741

          Priority: medium
            Bug ID: 71741
          Assignee: idr at freedesktop.org
           Summary: GL_ARB_ES3_compatibility and std140 arrays
        QA Contact: intel-3d-bugs at lists.freedesktop.org
          Severity: major
    Classification: Unclassified
                OS: Linux (All)
          Reporter: sheffmail at mail.ru
          Hardware: x86 (IA32)
            Status: NEW
           Version: 9.1
         Component: Drivers/DRI/i965
           Product: Mesa

Created attachment 89409
  --> https://bugs.freedesktop.org/attachment.cgi?id=89409&action=edit
std140 array bug

It appears that mesa 9.1.7 incorrectly handles arrays inside uniform blocks
with std140 layout when GL_ARB_ES3_compatibility is used. I've attached a
sample program, build it with:

gcc std140_bug.c -o std140_bug -lX11 -lGL -lm

The program draws a triangle, rotation angle is taken from a uniform buffer in
vertex shader like this:

float angle = rotations[1];

This should access 2'nd array element, but instead it accesses 5'th element, as
a result triangle is rotated by 85 degrees (appears narrow) when it should be
rotated by 0 degrees (appear wide)

glxinfo:
OpenGL vendor string: Intel Open Source Technology Center
OpenGL renderer string: Mesa DRI Intel(R) Ivybridge Desktop x86/MMX/SSE2
OpenGL version string: 3.0 Mesa 9.1.7
OpenGL shading language version string: 1.30
uname -a:
Linux xxx 3.11.0-13-generic #20~precise2-Ubuntu SMP Thu Oct 24 21:07:45 UTC
2013 i686 i686 i386 GNU/Linux

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