Question

我开始使用ECS，并且具有“旋转”组件（四元数）和“平移”组件（float3）。我正在编写一个可以处理用户输入并旋转和/或向前移动播放器的系统。

问题是我不知道该怎么做。我认为缺少现有的API。

// Before it was easy
if (Input.GetKey(KeyCode.W))
    var newPostion = new Vector3(player.Position.x, player.Position.y, 0.3f)
                    + _playerTransform.up * Time.deltaTime * PlayerSpeed;

if (Input.GetKey(KeyCode.A))
    _playerTransform.Rotate(new Vector3(0, 0, PlayerRotationFactor));

// now it is not - that's part of the system's code
Entities.With(query).ForEach((Entity entity, ref Translation translation, ref Rotation rotation) =>
{
    float3 tmpTranslation = translation.Value;
    quaternion tmpRotation = rotation.Value;

    if (Input.GetKey(KeyCode.W))
        // how to retrieve forward vector from the quaternion
        tmpTranslation.y += Time.deltaTime * PlayerSpeed; 

    if (Input.GetKey(KeyCode.A) || Input.GetKey(KeyCode.LeftArrow))
        // this always set the same angle
        tmpRotation = quaternion.RotateZ(PlayerRotationFactor); 

    // ECS need this
    var newTranslation = new Translation { Value = tmpTranslation };
    PostUpdateCommands.SetComponent(entity, newTranslation);
    var newRotation = new Rotation { Value = tmpRotation };
    PostUpdateCommands.SetComponent(entity, newRotation);
});

Answer 1

要从四元数中获取向量，只需将其与正向向量相乘即可，例如：

if (Input.GetKey(KeyCode.W))
{
    Vector forward = tmpRotation * float3(0,0,1);
    tmpTranslation += forward * Time.deltaTime * PlayerSpeed;
}

对于旋转部分，正如您所说的// this always set the same angle。看起来您正在创建一个新的静态角度。尝试更改以当前角度相乘，就像四元数相乘以合并一样。示例：

if (Input.GetKey(KeyCode.A) || Input.GetKey(KeyCode.LeftArrow))
{
    tmpRotation = mul(tmpRotation, quaternion.RotateZ(PlayerRotationFactor));
}

旁注：我还是Unity ECS的新手，我还没有测试以上代码。

Answer 2

// correct forward
if (Input.GetKey(KeyCode.W) || Input.GetKey(KeyCode.UpArrow))
{
    float3 forwardVector = math.mul(rotation.Value, new float3(0, 1, 0));
    newTranslation += forwardVector * Time.deltaTime * PlayerSpeed;
}
// correct rotation
if (Input.GetKey(KeyCode.A) || Input.GetKey(KeyCode.LeftArrow))
{
    quaternion newRotation = math.mul(rotation.Value, quaternion.RotateZ(PlayerRotationFactor * Time.deltaTime));
    // insert new value to the component
    PostUpdateCommands.SetComponent(entity, new Rotation { Value = newRotation });
}
// thx akaJag

如何在Unity（ECS）中旋转量变并计算方向矢量

2 个答案: