Question

所以我正在使用C ++为大学项目在虚幻引擎4中制作这个太阳能系统模拟器，但是，我是C ++和UE4的新手而且我在数学上很糟糕所以我需要一点帮助，我我现在想要使用Euler积分器来获得一些基本的物理学，然后绕地球运行月球轨道，然后继续使用Velocity Verlet方法并以这种方式构建整个太阳系。但是，截至目前，甚至欧拉集成也无效。这是Moon.cpp中的代码

//Declare the masses
float MMass = 109.456;
float EMass = 1845.833;

//New velocities
float NewMVelX = 0.0;
float NewMVelY = 0.0;
float NewMVelZ = 0.0;

//Distance
float DistanceX = 0.0;
float DistanceY = 0.0;
float DistanceZ = 0.0;

//Earth's velocity
float EVelocityX = 0.0;
float EVelocityY = 0.0;
float EVelocityZ = 0.0;

//Moon's base velocity
float MVelocityX = 0.1;
float MVelocityY = 0.0;
float MVelocityZ = 0.0;

//Moon's acceleration
float MForceX = 0.0;
float MForceY = 0.0;
float MForceZ = 0.0;

//New position
float MPositionX = 0.0;
float MPositionY = 0.0;
float MPositionZ = 0.0;

// Called every frame
void AMoon::Tick(float DeltaTime)
{
    Super::Tick(DeltaTime);

    //Get Earth Location
    FVector EPosition = FVector(0.0, 0.0, 0.0);

    //Get Moon Location
    FVector MPosition = GetActorLocation();

    //Get the distance between the 2 bodies
    DistanceX = (MPosition.X - EPosition.X) / 100;
    DistanceY = (MPosition.Y - EPosition.Y) / 100;
    //DistanceZ = MPosition.Z - EPosition.Z / 100; 


    //Get the acceleration/force for every axis
    MForceX = G * MMass * EMass / (DistanceX * DistanceX);
    MForceY = G * MMass * EMass / (DistanceY * DistanceY);
    //MForceZ = G * MMass * EMass / (DistanceZ * DistanceZ);


    //Get the new velocity
    NewMVelX = MVelocityX + MForceX;
    NewMVelY = MVelocityY + MForceY;
    //NewMVelZ = MVelocityZ + MForceZ * DeltaTime;

    //Get the new location
    MPositionX = (MPosition.X) + NewMVelX;
    MPositionY = (MPosition.Y) + NewMVelY;
    //MPositionZ = MPosition.Z * (MVelocityZ + NewMVelZ) * 0.5 * DeltaTime;

    //Set the new velocity on the old one
    MVelocityX = NewMVelX;
    MVelocityY = NewMVelY;
    //MVelocityZ = NewMVelZ;

    //Assign the new location
    FVector NewMPosition = FVector(MPositionX, MPositionY, MPositionZ);

    //Set the new location
    SetActorLocation(NewMPosition);

}

价值观可能不对，我此时正在进行测试。我将此代码基于我在Google和多个网站上获得的不同信息，但此时我很困惑。发生的事情是月亮刚开始向一个方向前进并且永不停止。我知道我的问题在于地球的力/加速度/实际重力，它应该拉动月球而不是将它推开。但无论如何，如果有人知道我做错了什么，我会非常感谢你听到你要说的话！感谢

Answer 1

力量取决于欧几里德，旋转不变距离。因此使用

distance = sqrt(distanceX²+distanceY²+distanceZ²)

force = - G*Emass*Mmass/distance²

forceX = force * X/distance
forceY = force * Y/distance
forceZ = force * Z/distance

速度的时间步进也是错误的，应该是

velocityX += forceX/Mmass * deltaTime
velocityY += forceY/Mmass * deltaTime
velocityZ += forceZ/Mmass * deltaTime

当然，位置更新还包含时间步

positionX += velocityX * deltaTime
....

太阳系模拟器物理集成问题（虚幻引擎4，C ++）

1 个答案: