I am developing an interactive visualizer for a project using Pangolin and OpenGL. The idea is as follows.
There are two threads:
| 1. Render Thread | 2. Process Thread |
|---|---|
- acquire lock and swap dataNew with dataDisplay, release lock- render dataDisplay on the window |
- read data - process data - acquire lock, copy data to dataNew buffer, release lock |
Sample code:
// Render loop
while (!pangolin::ShouldQuit()) {
if (mDataReadDone) break;
// ....some code.....
/*Critical section*/
// Can acquire lock only after mDataNew
// is updated with new data in the process thread
{
std::unique_lock<std::mutex> lock(mRenderMutex);
std::swap(mDataDisplay, mDataNew);
} /*Critical section*/
// .....Render mDataDisplay data.........
}
// data process loop
while (!mWindowClosed) {
// .....Read data....
// .....Process data....
// ....Copy data.....
/*Critical section*/
{
std::unique_lock<std::mutex> lock(mRenderMutex);
copyDataFromPipeline(mDataNew);
}
}
Question: In the render loop, for the std::swap() to happen, it has to wait till new data is filled in mDataNew buffer by the process thread and hence the render loop is blocked for some time. Can the render loop be blocked for some time by design in general?
Constraint - In my case, I have a pause option and also a time travel option to go back in frames to debug a particular frame if something is wrong there, so I cannot miss any frames for rendering
