bbb7a41743
## About The Pull Request ~~Kept you waitin huh!~~ The projectile refactor is finally here, 4 years later. This PR (almost) completely rewrites projectile logic to be more maintainable and performant. ### Key changes: * Instead of moving by a fixed amount of pixels, potentially skipping tile corners and being performance-heavy, projectiles now use raymarching in order to teleport through tiles and only visually animate themselves. This allows us to do custom per-projectile animations and makes the code much more reliable, sane and maintainable. You (did not) serve us well, pixel_move. * Speed variable now measures how many tiles (if SSprojectiles has default values) a projectile passes in a tick instead of being a magical Kevinz Unit™️ coefficient. pixel_speed_multiplier has been retired because it never had a right to exist in the first place. __This means that downstreams will need to set all of their custom projectiles' speed values to ``pixel_speed_multiplier / speed``__ in order to prevent projectiles from inverting their speed. * Hitscans no longer operate with spartial vectors and instead only store key points in which the projectile impacted something or changed its angle. This should similarly make the code much easier to work with, as well as fixing some visual jank due to incorrect calculations. * Projectiles only delete themselves the ***next*** tick after impacting something or reaching their maximum range. Doing so allows them to finish their impact animation and hide themselves between ticks via animation chains. This means that projectiles no longer disappear ~a tile before hitting their target, and that we can finally make impact markers be consistent with where the projectile actually landed instead of being entirely random. <details> <summary>Here is an example of how this affects our slowest-moving projectile: Magic Missiles.</summary> Before: https://github.com/user-attachments/assets/06b3a980-4701-4aeb-aa3e-e21cd056020e After: https://github.com/user-attachments/assets/abe8ed5c-4b81-4120-8d2f-cf16ff5be915 </details> <details> <summary>And here is a much faster, and currently jankier, disabler SMG.</summary> Before: https://github.com/user-attachments/assets/2d84aef1-0c83-44ef-a698-8ec716587348 After: https://github.com/user-attachments/assets/2e7c1336-f611-404f-b3ff-87433398d238 </details> ### But how will this affect the ~~trout population~~ gameplay? Beyond improved visuals, smoother movement and a few minor bugfixes, this should not have a major gameplay impact. If something changed its behavior in an unexpected way or started looking odd, please make an issue report. Projectile impacts should now be consistent with their visual position, so hitting and dodging shots should be slightly easier and more intuitive. This PR should be testmerged extensively due to the amount of changes it brings and considerable difficulty in reviewing them. Please contact me to ensure its good to merge. Closes #71822 Closes #78547 Closes #78871 Closes #83901 Closes #87802 Closes #88073 ## Why It's Good For The Game Our core projectile code is an ungodly abomination that nobody except me, Kapu and Potato dared to poke in the past months (potentially longer). It is laggy, overcomplicated and absolutely unmaintaineable - while a lot of decisions made sense 4 years ago when we were attempting to introduce pixel movement, nowadays they are only acting as major roadblocks for any contributor who is attempting to make projectile behavior that differs from normal in any way. Huge thanks to Kapu and Potato (Lemon) on the discord for providing insights, ideas and advice throughout the past months regarding potential improvements to projectile code, almost all of which made it in. ## Changelog 🆑 qol: Projectiles now visually impact their targets instead of disappearing about a tile short of it. fix: Fixed multiple minor issues with projectile behavior refactor: Completely rewrote almost all of our projectile code - if anything broke or started looking/behaving oddly, make an issue report! /🆑
Unit Tests
What is unit testing?
Unit tests are automated code to verify that parts of the game work exactly as they should. For example, a test to make sure that the amputation surgery actually amputates the limb. These are ran every time a PR is made, and thus are very helpful for preventing bugs from cropping up in your code that would've otherwise gone unnoticed. For example, would you have thought to check that beach boys would still work the same after editing pizza? If you value your time, probably not.
On their most basic level, when UNIT_TESTS is defined, all subtypes of /datum/unit_test will have their Run proc executed. From here, if Fail is called at any point, then the tests will report as failed.
How do I write one?
- Find a relevant file.
All unit test related code is in code/modules/unit_tests. If you are adding a new test for a surgery, for example, then you'd open surgeries.dm. If a relevant file does not exist, simply create one in this folder, then #include it in _unit_tests.dm.
- Create the unit test.
To make a new unit test, you simply need to define a /datum/unit_test.
For example, let's suppose that we are creating a test to make sure a proc square correctly raises inputs to the power of two. We'd start with first:
/datum/unit_test/square/Run()
This defines our new unit test, /datum/unit_test/square. Inside this function, we're then going to run through whatever we want to check. Tests provide a few assertion functions to make this easy. For now, we're going to use TEST_ASSERT_EQUAL.
/datum/unit_test/square/Run()
TEST_ASSERT_EQUAL(square(3), 9, "square(3) did not return 9")
TEST_ASSERT_EQUAL(square(4), 16, "square(4) did not return 16")
As you can hopefully tell, we're simply checking if the output of square matches the output we are expecting. If the test fails, it'll report the error message given as well as whatever the actual output was.
- Run the unit test
Open code/_compile_options.dm and uncomment the following line.
//#define UNIT_TESTS //If this is uncommented, we do a single run though of the game setup and tear down process with unit tests in between
There are 3 ways to run unit tests
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Run tgstation.dmb in Dream Daemon. Don't bother trying to connect, you won't need to. You'll be able to see the outputs of all the tests. You'll get to see which tests failed and for what reason. If they all pass, you're set!
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Launch game from VS Code. Launch the game as normal & you will see the output of your unit tests in your fancy chat window. This is preferred as you can use the debugger to step through each line of your unit test & can use the games inbuilt debugging tools to further aid in testing
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Use VS Code Tgstation Test Explorer Extension. This allows you to run tests without launching the game & can also run focused tests(either a single or a selected group)
How to think about tests
Unit tests exist to prevent bugs that would happen in a real game. Thus, they should attempt to emulate the game world wherever possible. For example, the quick swap sanity test emulates a real scenario of the bug it fixed occurring by creating a character and giving it real items. The unrecommended alternative would be to create special test-only items. This isn't a hard rule, the reagent method exposure tests create a test-only reagent for example, but do keep it in mind.
Unit tests should also be just that--testing units of code. For example, instead of having one massive test for reagents, there are instead several smaller tests for testing exposure, metabolization, etc.
The unit testing API
You can find more information about all of these from their respective doc comments, but for a brief overview:
/datum/unit_test - The base for all tests to be ran. Subtypes must override Run(). New() and Destroy() can be used for setup and teardown. To fail, use TEST_FAIL(reason).
/datum/unit_test/proc/allocate(type, ...) - Allocates an instance of the provided type with the given arguments. Is automatically destroyed when the test is over. Commonly seen in the form of var/mob/living/carbon/human/human = allocate(/mob/living/carbon/human/consistent).
TEST_FAIL(reason) - Marks a failure at this location, but does not stop the test.
TEST_ASSERT(assertion, reason) - Stops the unit test and fails if the assertion is not met. For example: TEST_ASSERT(powered(), "Machine is not powered").
TEST_ASSERT_NOTNULL(a, message) - Same as TEST_ASSERT, but checks if !isnull(a). For example: TEST_ASSERT_NOTNULL(myatom, "My atom was never set!").
TEST_ASSERT_NULL(a, message) - Same as TEST_ASSERT, but checks if isnull(a). If not, gives a helpful message showing what a was. For example: TEST_ASSERT_NULL(delme, "Delme was never cleaned up!").
TEST_ASSERT_EQUAL(a, b, message) - Same as TEST_ASSERT, but checks if a == b. If not, gives a helpful message showing what both a and b were. For example: TEST_ASSERT_EQUAL(2 + 2, 4, "The universe is falling apart before our eyes!").
TEST_ASSERT_NOTEQUAL(a, b, message) - Same as TEST_ASSERT_EQUAL, but reversed.
TEST_FOCUS(test_path) - Only run the test provided within the parameters. Useful for reducing noise. For example, if we only want to run our example square test, we can add TEST_FOCUS(/datum/unit_test/square). Should never be pushed in a pull request--you will be laughed at.
Final Notes
- Writing tests before you attempt to fix the bug can actually speed up development a lot! It means you don't have to go in game and folllow the same exact steps manually every time. This process is known as "TDD" (test driven development). Write the test first, make sure it fails, then start work on the fix/feature, and you'll know you're done when your tests pass. If you do try this, do make sure to confirm in a non-testing environment just to double check.
- Make sure that your tests don't accidentally call RNG functions like
prob. Since RNG is seeded during tests, you may not realize you have until someone else makes a PR and the tests fail! - Do your best not to change the behavior of non-testing code during tests. While it may sometimes be necessary in the case of situations such as the above, it is still a slippery slope that can lead to the code you're testing being too different from the production environment to be useful.