On Sun, Jul 15, 2012 at 11:17 PM, Kai Sterker <kai.ster...@gmail.com> wrote:
This weekends code changes aren't ready to commit, but I made some progress, but also uncovered more problems. > Added a real z-coordinate to the pathfinding, and that alone allows a > character to find its way down to a lower level. Up does not work yet, > as the collision check cannot distinguish between a stair and other > blocking objects. Going up stairs also works now, although not perfectly. There are instances where the nodes falling on the stairs get skipped and even if they are present, sometimes the character fails to follow them. Latter might be a problem with the collision detection. Although right now I do not understand why it works for the player, but sometimes not for the NPC. > There's another problem, however, that needs to be solved first. Since > a path can now be found on different levels, the number of iterations > allowed to calculate the path is too small. The solution I implemented for that now tries to process nodes on the same level as the goal first. That should work well when the terrain is not too complex and multiple up/down level changes are required. All in all, the allotted number of iterations for pathfinding needs to be increased as well. But to allow that, the actual finding of the path needs to be distributed over several frames (maybe allowing 1000 iterations per frame(. This change shouldn't be too difficult, but it will require to keep some data around that right now is only kept locally. And we must ensure that multiple simultaneous pathfinding operations each use their own set of data. So there is still work to do, and there are two more issues that need to be addressed: Following along the path does not work well if the NPC deviates too much from that path, i.e. due to being deflected by obstacles. So I think that piece of code (https://github.com/ksterker/adonthell/blob/master/src/world/pathfinding_manager.cc#L342) needs to be rewritten. I tried patching it up, but wasn't really successful. So maybe starting with a fresh design would be the better solution. Another bit that bothers me is the case when the path gets suddenly blocked (i.e. by another character getting in the way). Right now it throws the whole path away and calculates a new one. The better approach might be to only remove the blocked nodes and newly calculate the path to the first unblocked node. Only if no such path can be found, we should try to find a completely new path to the goal. And lastly, I have run into another issue with the collision code. When the NPC fell down from a higher level, his z position should have been -72.0, as that is where the ground floor is located. Instead it ended up at -72.18 and from that time on, he became stuck in the floor. Again, I haven't really been able to reproduce it with the player character, but it happens quite regularly with the NPC. So with all those open items, I guess it might be at least two more weekends before having something ready to show. But if anyone feels like helping out, I can open a branch for you to see where I'm at. Kai _______________________________________________ Adonthell-devel mailing list Adonthell-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/adonthell-devel
