在运行时创建具有可引用ID的变量

Question

I am creating a 3D modeling app that will store the vertex points in a bunch of variables, one for each. I need to be able to dynamically add or remove vertex points which calls for dynamically adding or removing these variables. Each face will reference these points with an ID linking to the variable containing the point coordinates. Is there a way to create and destroy variables at runtime? Is there a better way to accomplish this with an existing data type? I don't think an array will work because these need to be independent in order to be added or removed easily. I also can't directly store the coordinates of the points because a floating point error or other small change would make duplicate points next to each other.

Answer 1

Consider using a Dictionary (as Alexei pointed out in his comment). A Dictionary is very fast for adding, removing and retrieving values.

As for the key, options include

• A sequential int
• A long that is a hash based on data in the vertex
• Worst case a Guid

A sequential int would work well in many use cases, though if you have multiple threads requesting new IDs you would have slight contention getting the next ID (and be sure you follow best practices for threading).

A long hash risks collisions, eg if the hash is derived from the coordinates and you can have multiple vertices under management with the same coordinates (vertices with different coordinates run the normal risk of hash collisions).

A Guid is pretty large for a key, especially if there are many points, but is guaranteed to be unique.