While developing Hop Raider we found a rare glitch in floor’s tiles: sometimes they had an additional semi-transparent border line which was not supposed to be there. We discovered that some sprites were taking a bigger bounding box than they were supposed to, so when a sprite was drawn an additional line taken from adjacent sprites in the spritesheet was also drawn.

If you look carefully (or not so carefully) to the rock base floor in Hop Raider 1.2.1 or older you can see this glitch. It happens in lava tiles too. And this glitch is iOS/Android-independent. This usually happens in rock base floor, lava and sometimes in right-side dirt floors.

As it was somehow random (and actually it didn’t impact in gameplay and didn’t break overall game experience) we didn’t prioritise fixing this glitch but today I have been able to fix it and wanted to share both, the reason of and the solution to the problem.