jimrange
commented
9 years ago I think this bug is probably a result of parameters that set by the user of the API when tuning the physics engine.
If the physics step is too small or a physics computation takes too much time to complete, then non-converging integration calculations can result in the physics engine due to large time deltas. The result of exploding non-converging values is what you describe as sudden and extreme movement of the physics bodies.
I have been successful at fixing this issue by increasing the substeps, e.g. scene->getPhysicsWorld()->setSubsteps(10); The number 10 here is arbitrary and largely dependent on the physics model you are simulating and how much other CPU is being used by other game code.
Bottom line, getting a physics engine such as Chipmunk to be stable can require some testing and fine tuning. Test on a least-common-denominator device and play around with the substep setting, how many physics objects your game uses, and other CPU hungry game code to find something that works.
A Possible Fix For the Cocos2d-x Code --- A hackish fix to prevent this is to check the time delta that the physics engine is getting stepped at. If it is bigger than, maybe a tenth of a second, then force it to be a tenth of a second. This can lead to undesirable effects in your game (time loss in the physics simulation), but it guarantees physics engine stability in that it eliminates large time delta's from ever occurring.
minggo
jeason1997
3.x 版本封装的物理引擎，刚体有时候会突然猛烈运动，最后弹出包围盒。
这不是我一个人才有的BUG，我搜索了下论坛里的其他帖子，发现不少人有这个问题。
就算是静止的刚体，有时候也会突然剧烈弹起来。
而且这个BUG的发生有一定偶然性。