private static float PickItem(ref Vector4 target, SwizzleItem item)
{
switch (item)
{
case SwizzleItem.X:
return(target.x);
case SwizzleItem.Y:
return(target.y);
case SwizzleItem.Z:
return(target.z);
case SwizzleItem.W:
return(target.w);
default:
throw new ArgumentOutOfRangeException(nameof(item), item, $"Cannot pick swizzle item from {target}: unrecognized item name");
}
}
/// <summary>
/// 重组向量分量
/// </summary>
/// <param name="value">目标向量</param>
/// <param name="item1">分量1</param>
/// <param name="item2">分量2</param>
/// <returns></returns>
public static Vector2 Swizzle(this Vector4 value, SwizzleItem item1, SwizzleItem item2)
{
return(new Vector2(PickItem(ref value, item1), PickItem(ref value, item2)));
}
/// <summary>
/// 重组向量分量
/// </summary>
/// <param name="value">目标向量</param>
/// <param name="item1">分量1</param>
/// <param name="item2">分量2</param>
/// <param name="item3">分量3</param>
/// <param name="item4">分量4</param>
/// <returns></returns>
public static Vector4 Swizzle(this Vector4 value, SwizzleItem item1, SwizzleItem item2, SwizzleItem item3, SwizzleItem item4)
{
return(new Vector4(PickItem(ref value, item1), PickItem(ref value, item2), PickItem(ref value, item3), PickItem(ref value, item4)));
}
/// <summary>
/// 重组向量分量
/// </summary>
/// <param name="value">目标向量</param>
/// <param name="item1">分量1</param>
/// <param name="item2">分量2</param>
/// <param name="item3">分量3</param>
/// <returns></returns>
public static Vector3 Swizzle(this Vector3 value, SwizzleItem item1, SwizzleItem item2, SwizzleItem item3)
{
return(new Vector3(PickItem(ref value, item1), PickItem(ref value, item2), PickItem(ref value, item3)));
}