One of the things which are very peculiar about graphics development is how tricky it is to hunt bugs down. You often have to resort to visual tracing in order to actually be able to experience the “ah-hah!” Archimedes moment.
I have spent a great deal of my free time recently to track down the problem that was causing my particles to fall behind geometry. Were it not the visual hints, I would probably have not been able to tell for the next month that it was AABB/ray intersection test implementation in my OpenCL code that was returning negative values for cases which should be reporting collisions.
Oh well. Let’s move on.