Refactor missiles.cpp to use Direction enum instead of magic Point/Displacement constants

[ephphatha]

There are multiple places in missiles.cpp which iterate through tiles adjacent to a given location.

https://github.com/diasurgical/devilutionX/blob/5537fe748e63b06ed2e474f7dea6ebd1216fa3d3/Source/missiles.cpp#L1634 https://github.com/diasurgical/devilutionX/blob/5537fe748e63b06ed2e474f7dea6ebd1216fa3d3/Source/missiles.cpp#L3417 https://github.com/diasurgical/devilutionX/blob/5537fe748e63b06ed2e474f7dea6ebd1216fa3d3/Source/missiles.cpp#L3995 https://github.com/diasurgical/devilutionX/blob/5537fe748e63b06ed2e474f7dea6ebd1216fa3d3/Source/missiles.cpp#L4017 https://github.com/diasurgical/devilutionX/blob/5537fe748e63b06ed2e474f7dea6ebd1216fa3d3/Source/missiles.cpp#L4772

These lists could be directly replaced with a list of the appropriate Direction enum constants. This would retain the same behaviour as existing code while making the intent clearer.

[ephphatha]

There is similar code in player.cpp and towners.cpp (probably plenty of other places). If you were feeling keen and wanted to clean up other files I'd recommend limiting PRs to a single file per commit to make it easier to review 😃

[agris-codes]

Does “good first issue” mean a good issue for a newcomer to the project to tackle, rather than a good writeup of the issue by the poster?

[AJenbo]

Does “good first issue” mean a good issue for a newcomer to the project to tackle, rather than a good writeup of the issue by the poster?

yes https://goodfirstissue.dev/language/cplusplus

[agris-codes]

Does “good first issue” mean a good issue for a newcomer to the project to tackle, rather than a good writeup of the issue by the poster?

yes https://goodfirstissue.dev/language/cplusplus

Thanks, I’ll tackle this issue then if the turn-around time required isn’t < 1 week.

[julealgon]

I imagine some instances could just turn into:

for (auto direction in enum_values<Direction>())
    ...

?

[ephphatha]

Definitely for the lines linked, they only end up being used for CheckMissileCollision and all cases get executed (no early returns) so directions don't need to be tested in a specific order. I'm not sure if other code depends on the list order.

[nathanafox-us]

Hello. I believe I edited the code in missiles.cpp to use the enum directions in those places rather than the magic numbers. I would like to request a push, but this is my first time contributing to a project. How would I go about doing it in this instance?

[AJenbo]

Well actually you create a Pull Request, which we then have to approve. First push your code to your fork on GitHub (Sergentfox234/devilutionX). You then go to https://github.com/diasurgical/devilutionX/pulls where you should see a green button for creating your Pull Request.

[nathanafox-us]

Ok. I pushed to the pull request.

[nathanafox-us]

Ok. It should be good to go now!

[AJenbo]

Thanks, I made a review and added some comments as feedback.