https://bugs.freedesktop.org/show_bug.cgi?id=80419
--- Comment #95 from Jose Fonseca jfonseca@vmware.com --- (In reply to Roland Scheidegger from comment #94)
Created attachment 120734 [details] [review] apitrace patch for honoring range in DrawRangeElementsX commands
So you'd want something like this (totally untested) patch for apitrace? Makes sense I guess that the specified range not only means the supplied indices have to be inside that range, but it also works the other way round (driver can rely on the specified range being accessible) - otherwise the driver would still need to scan the actual index buffer. (Albeit since for this app the ranges seem to be pretty bogus who knows if the memory inside the specified range but not used in the actual indices is really always accessible.)
Yes, this does indeed make sense.
For VBOs, the start/end range is a hint (the OpenGL shouldn't crash if the start/end range goes beyond the VBO size), but for user memory arrays, there's no reliable way to know where user memory is supposed to stop -- the start/end range is it.
I am actually wondering if it would be legal if the memory isn't accessible below the start value (apitrace surely couldn't handle that)...
I don't think it's worth worrying about that.