Mercurial > hg > openttd
changeset 18580:8161974848f8 draft
(svn r23425) -Document [FS#4815]: why vehicles might be continuously changing speed up and down
| author | rubidium <rubidium@openttd.org> |
|---|---|
| date | Sun, 04 Dec 2011 12:07:19 +0000 |
| parents | 7174f703afc5 |
| children | 00d5b9938a9d |
| files | known-bugs.txt |
| diffstat | 1 files changed, 20 insertions(+), 0 deletions(-) [+] |
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--- a/known-bugs.txt +++ b/known-bugs.txt @@ -338,3 +338,23 @@ it does not add anything to gameplay. Nevertheless trains shall not crash in normal operation, so making a train not crash with itself is the best solution for everyone. + +Vehicles not keeping their "maximum" speed [FS#4815]: + Vehicles that have not enough power to reach and maintain their + advertised maximum speed might be constantly jumping between two + speeds. This is due to the fact that speed and its calculations + are done with integral numbers instead of floating point numbers. + As a result of this a vehicle will never reach its equilibrium + between the drag/friction and propulsion. So in effect it will be + in a vicious circle of speeding up and slowing down due to being + just at the other side of the equilibrium. + + Not speeding up when near the equilibrium will cause the vehicle + to never come in the neighbourhood of the equilibrium and not + slowing down when near the equilibrium will cause the vehicle + to never slow down towards the equilibrium once it has come down + a hill. + + It is possible to calculate whether the equilibrium will be + passed, but then all acceleration calculations need to be done + twice.