Comme=
nt # 22
on bug 11107=
7
from roland@rptd.ch
Hi Marek,
This is going to be complicated. The application is not yet free to use by
others (working on getting it to release shape). I would have to figure out
first how to break this down into a reproducible test case since I don't kn=
ow
myself what triggers the bug.
If you can think of some corner values to narrow down in what direction to
search I can fully mess with the source code over here. The faulty commit t=
alks
about UBO maximum size so this might be a start. The OpenGL Capabilities fr=
om
the GPU is this:
- UBO Maximum Block Size =3D 65536
- UBO Buffer Offset Alignment =3D 4
So the maximum size used by the application is 65536 bytes.
UBOs are used as shared buffers so blocks of data are placed next to each o=
ther
respecting alignment and updated.
UBOs are created like this:
glBindBuffer(GL_UNIFORM_BUFFER, pUBO) // <=3D done once
glBufferData(GL_UNIFORM_BUFFER, bufferSize, NULL, GL_DYNAMIC_DRAW) // <=
=3D done
once
glMapBufferRange(GL_UNIFORM_BUFFER, stride * elementCount, elementStride,
GL_WRITE_ONLY | GL_MAP_INVALIDATE_RANGE_BIT) // <=3D done for each data=
block
written
Data then written and unmapped
In particular this means a larger UBO is created once then individual blocks
are written to it using ranged mapping. Just a wield guess but could the
problem be related to this kind of usage pattern?