Csv Spawner Notification Bus

[w-czerski]

About:

This PR introduces a notification bus for the CSV spawner.
It provides the ability to trigger actions when entities are spawned and to gather information when the spawning process begins.
This is particularly useful when there is a need to react to the moment "when entities are spawned".

Merge order:

This branch is a copy of wc/spline_publisher. I've tested it already with new changes.
#109 -> #108 -> main

[arturkamieniecki]

There is a lot of info passed in the bus calls. Verify if everything is needed. Consider creating a struct for this data.

Overall looks good!

[w-czerski]

Sure, it’s just a quick fix that I needed. A lot of the information is indeed unnecessary. I’ll refactor it soon.

On further thought, it might be better to introduce some global robotec-o3de-tools notification buses to reduce dependencies? This way, we would only need to include the notification bus in CMake once, instead of creating dependencies for individual tools like spline tools, geo json, csv spawner, etc.

[patrykantosz]

Code looks okay. I'm just curious if anything (beyond this PR, as it is obvious the implementation is not here) implements handlers for these two newly added functions? Or has the bus been created for some further work planned for the future?

[w-czerski]

In current state, we need some explicit logic to handle is terrain created (please look at #102).
This is just a helpful functionality to prevent users to stacks tick frames, or queue functions. User can directly do something on spawn ready, and skip in most cases terrain handling (since this is not useful or needed for user).

Exactly this functionality is needed in one project I'm working on. I would reconsider what information should be passed down in the buses. Right now notification is only needed.

[w-czerski]

I've added:

• more context with descriptions
• default implementation of events (do nothing - we don't want to force override of each not implemented function)
• introduced struct with info
• added a enum result status code for the spawn finished process
  Let me know what you think. I've made it more generic for the future.

[jhanca-robotecai]

What is the reason for putting utilities in the public API?

[jhanca-robotecai]

Are the bitshifts needed here? Typically, the bitshifts are used when multiple flags can happen at once.

[jhanca-robotecai]

const has no use in definitions, hence it should be used only to increase the readability of the code. m_statusCode indicates success, failure and warnings, but the const indicator would suggest the value will not be changed by the method, hence the indication will not take any place.

[jhanca-robotecai]

Shouldn't the interface method stay purely virtual?

[jhanca-robotecai]

Please implicitly set such flags to success (or failure) during initialization to avoid problems in the future.

[pijaro]

No need for Code postfix.

SpawnStatus is enough.

[pijaro]

Keep it simpler:

Suggested change

	SpawnStopped = 1 << 1, ///< Spawning was stopped prematurely but not necessarily a failure.
	ErrorOccurred = 1 << 2, ///< An error occurred during spawning (potentially recoverable).
	Stopped = 1 << 1, ///< Spawning was stopped prematurely but not necessarily a failure.
	Error = 1 << 2, ///< An error occurred during spawning (potentially recoverable).

[pijaro]

Why const references in this struct? Huge dangling reference risk here (I can imagine someone waits a frame or two after acquiring the status - the referenced objects might be gone then).