Extract only valid surfels from GPU to CPU

[BruceCanovas]

Hi,

I am actually using your solution as part of ROS node and was wondering if there was a way to get directly from the GPU only the valid surfels. Because model->downloadMap() extracts even the invalid surfels and so as to publish a point cloud it would be faster to loop only through valid ones. Or do you have a hint about what can I change in the source code to make it possible?

Thank you

[martinruenz]

You are right, at the moment the easiest solution is to use downloadMap and then to filter on the CPU, see:

co-fusion/Core/CoFusion.cpp

Line 703 in 457c3a0

if (conf > model->getConfidenceThreshold()) {

Alternatively you could write an OpenGL-based filter using Transform Feedback or similar.

[BruceCanovas]

Thank you, I ended up using transform feedback and an atomic counter to get the number of valid points. It is maybe not the smartest way but it seems to make the trick.

[martinruenz]

Cool, if this works nicely a pull request would be welcome! :)

[BruceCanovas]

Ok I will just take time to see how it works as I am quit new with github and clean a bit what I've added before.