Discrepancy between what my application shows, and what the trace plays back (OpenGL)

[Babis Koniaris]

Hi,

I was looking onto a problem where my application displays what I expect 
on one PC (PC0) and exhibits a bug on another (PC1). PC0 has a nice 
powerful Geforce TITAN, while PC1 is a laptop intel integrated card. I'm 
running an application on OpenGL 4.00 (GLSL 4.00) which is supported on 
both.

The problem lies with reading the contents of a particular texture 
(R16UI): on PC1 the shader always reads zeroes, while on PC0 it reads 
the values normally. There are no OpenGL errors. Here is when I decided 
to run apitrace to find out what's going on.

I run qapitrace (latest version) and exit the application after a while, 
all while seeing the problem. I hit replay, and *the trace plays 
correctly, as in PC0. *After a bit of fiddling, I realized that if, in 
the Replay menu, "Error Checking" is selected, then the trace plays 
correctly as in PC0. If it's not selected, then it shows the bug as usual.

What could be going on?

Thanks,
Babis
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