Bullet Physics is random because the solver is random,please support developer select the solver's mode or reset the solver's random seed

[longchuan]

Use Case

when I run the physics,the result was random.I read the bullet code,found the problem is random seed.Bullet support the random seed's reset,but cocos did not support it.

Problem Description

the physics' result is random,frame sync was blocked.If player restart the app,and reconnect the game,the physics' result will be different.If support the random seed's reset,developer can reset all seed to ensure the result's consistent.

Proposed Solution

No response

How it works

No response

Alternatives Considered

support reset the random seed or solver's mode select

Additional Information

No response

[minggo]

I don't quite understand the result is random.

I read the bullet code, found the problem is random seed.Bullet support the random seed's reset

Could you describe it in detail? Thanks.

[longchuan]

I don't quite understand the result is random.

I read the bullet code, found the problem is random seed.Bullet support the random seed's reset

Could you describe it in detail? Thanks.

relaunch the scene,the result will be different,such as the order of many balls' collision.

[longchuan]

search the codes,you will find the random seed.

[longchuan]

I don't quite understand the result is random.

I read the bullet code, found the problem is random seed.Bullet support the random seed's reset

Could you describe it in detail? Thanks.

I bind the method,found the seed always be 0,there should have another reason.When I relaunch the scene, the result would be diffrent,But If I restart the app,the result would be same.So the random result was caused by random seed.

[longchuan]

Demo has a method to reset a scene,maybe can solve the problem

[longchuan]

Yes,I solved the problem.

void DLL_EXPORT ccDiscreteDynamicsWorld_reset(int dispatcher,int broadphase,int solver)
{
        btCollisionDispatcher *m_dispatcher = (btCollisionDispatcher *)dispatcher;
        btDbvtBroadphase *m_broadphase = (btDbvtBroadphase *)broadphase;
        btConstraintSolver *m_solver = (btConstraintSolver *)solver;
        m_broadphase->resetPool(m_dispatcher);
        m_solver->reset();
 }