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所以我在 Unreal Engine 4 中使用 C++ 为大学项目制作这个太阳系模拟器，但是，我是 C++ 和 UE4 的新手，而且我的数学很烂，所以我需要一些帮助，我想使用欧拉积分器现在只是为了获得一些基本的物理学知识并让月球绕地球运行，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，到目前为止，即使是欧拉积分也不起作用。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);

}

值可能不正确，此时我只是在进行测试。我将这段代码基于我在谷歌和多个网站上获得的不同信息，但在这一点上我很困惑。正在发生的事情是，月球只是开始朝 1 个方向移动，并且从未停止过。我知道我的问题在于地球的力/加速度/实际重力，它应该拉月球而不是推开它。但无论如何，如果有人知道我做错了什么，我会很感激听到你要说的话！谢谢

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1 回答 1

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力取决于欧几里得、旋转不变的距离。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

速度的时间步长也是错误的，应该是

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

当然，位置更新也包含时间步长

positionX += velocityX * deltaTime
....
于 2015-07-08T16:31:17.687 回答