behind osgText::Text. I made it so the box would get drawn using
whichever BackdropImplementation was selected. However, I did not
implement STENCIL_BUFFER. In that case it defaults to drawing the
bounding box using POLYGON_OFFSET instead.
Also made it so the BOUNDINGBOX and FILLEDBOUNDINGBOX are drawn with a
settable color and margin size.
While I was at it I tightened up the values applied with DEPTH_RANGE
and POLYGON_OFFSET, not just for drawing the bounding box but also for
drawing backdrop text (these values must be coupled since the bounding
box has to be drawn deeper in Z than the backdrop text). The values
in use before seemed like overkill and I was seeing some z-clipping
with my background scenery in the case of DEPTH_RANGE. If there was a
good reason for the large values please let me know...."
even if they have had DataVariance DYNAMIC explicitly specified. Then
when an application attempts to dynamically update the geometry in the
frame loop the primitive sets and data arrays are no longer as
expected, leading to display and/or memory corruption.
Attached is a simple fix. "
Note from Robert Osfield, tweaked Colin's changes to that it use != DYNAMIC as the the test rather than == STATIC.
When using more than one view logosCullCallback function is called without checking context ID from the cull visitor is equal to logo _contextID variable. It involves updating logo's viewport with different sizes.
So I made a fix well working, at least the way I use the plugin."
Note, from Robert Osfield, changed code to return true to signal culling of logo when being applied to a window that it wasn't assigned to.
while in an else clause. When if is true the phase changes and the
while condition will always by false, so might as well put the while
in the else to skip the check. There's also a benefit to having the
code logic similar between platforms.
"
Barrier operations. The error is with atomic operations in the
win32 condition implementation. The attached sample program will
reliably trigger with as few as three threads and a dual core system,
though sometimes it will take 65,000 iterations.
2.8.1 was the base for these changes
Win32ConditionPrivateData.h
Win32ConditionPrivateData::wait does two operations to decrement
waiters_ then read, when InterlockedDecrement decrements and returns
the value in one operation. The two operations allows another thread
to also decrement with both getting 0 for an answer.
Win32ConditionPrivateData::broadcast is using waiters_ directly
instead of using the w value read earlier, if it was safe to use
waiters_ directly there would be no need for InterlockedGet or w.
overview of deadlock in barrier with three threads
one thread in broadcast, 2 threads in wait,
release semaphore 2, waits on waiters_done_
both threads wake, decrement waiters_, get 0 for w,
<logic error here>
one calls set waiters_done_,
broadcast thread comes out of waiters_done_,
other thread calls waiters_done_, (which leaves waiters_done_ in the
signaled state)
<sets the trap>
broadcast thread returns releases mutex, other threads get
mutex and also return,
next barrier, first two threads enter wait, one goes to broadcast, release
semaphore 2, skips waiters_done_ as it had been released last time
returns, processes, enters the barrier for the next barrier operation
and waits,
three threads are now in wait, two have the previous barrier phase,
one the current phase, there's one count left in the semaphore which a
thread gets, returns, enters the barrier as a waiter, sleeps, and the
deadlock is completed"
GraphicsWindowCocoa-implementation, which enhances multithreaded
stability, it ensures that modifications to the size of an openglcontext
is done only from one thread.
"
