Debugging Initiatives in Godot | Kodeco

It would come as a shock, however not all code works on the primary attempt. (Insert stunned copyright-safe yellow electrical rodent right here)

For that reason, most built-in improvement environments (IDEs) embrace a debugger that permits the developer to identify and clear up points in the course of the a number of improvement iterations. That is illustrated by the next pseudocode:

whereas growing == true:
    code
    check
    debug

When growing a sport, nonetheless, there are different points to consider, corresponding to sport stability or verifying behaviors that may be too quick or delicate to note throughout gameplay.

Give it some thought. You rigorously crafted your sport’s problem degree, so that you need to be certain that it’s as much as the problem. However how are you going to rely the variety of enemies in a sport once they’re shifting round and capturing at you?
You would possibly need to verify the sport stability. Is the variety of enemies spawned at a given immediate what you count on? Did the power-up add the harm increase you anticipated?

These are only a few of the questions you would possibly need to reply whereas testing your sport. That is the place Godot’s debug instruments turn out to be useful, serving to you check and confirm all that.

Getting Began

The instance challenge is identical from the Publishing Your Godot Challenge to itch.io tutorial. Nonetheless, for this text, the code was modified to reinforce the gameplay expertise. Sadly, the sport broke within the course of and you might want to discover what’s incorrect with it utilizing the debug instruments. How handy! :]

You may obtain the challenge utilizing the Obtain supplies hyperlinks on the prime and backside of this text. Be aware that this challenge requires Godot 4.3 or newer to run.

The beginning challenge has the identical construction as within the earlier article, however three recordsdata have modified: projectile.gd, enemy_ship.gd, and main_game.gd.

Now is an efficient time to obtain and run the challenge to evaluate the way it’s working and see how the bugs affect the sport. The primary situation you’ll discover is that it’s not possible to destroy the enemy ships, though they’ll destroy your ship, so it’s debugging time!

Overview of the Debug Instruments

Godot has a set of highly effective debug instruments you need to use to evaluate code for logic errors, or graphics for efficiency points, and even to get an x-ray of how the sport is utilizing its processing time.

Though there’s a Debug menu on the prime of the display screen, this text will deal with the instruments accessible by the Debugger panel on the backside of the display screen, as a result of these are the instruments that collect info when executing the challenge by the Run the challenge button.

Debugger Panel

The debugger panel, positioned on the backside of the display screen by default, is accessible from the Debugger possibility on the backside of the window, to the appropriate of the Output possibility. The next image reveals the debug panel:

On the panel’s prime, you may see a couple of tabs. From left to proper, the tabs are:

1. Stack hint: Exhibits the execution stack, the context and its variables, and permits for controlling how the sport executes in the course of the debug session. You’ll be taught extra about this tab later on this article.
2. Errors: Exhibits the error and warning messages in the course of the sport execution.
3. Profiler: Exhibits which code is working and the way it impacts the sport efficiency. You’ll be taught extra about this tab later on this article.
4. Visible profiler: Shows a graph displaying which code is working and the way a lot time it takes for execution. You’ll be taught extra about this tab later on this article.
5. Screens: Incorporates graphs of sport info, corresponding to frames per second (fps), reminiscence utilization, scene nodes, and extra. The information from the debug session is saved even after the session is over, so it’s doable to evaluate it even after execution.
6. Video RAM: Exhibits a listing of assets and the way a lot video RAM they use whereas working, in addition to the grand whole on the prime of the panel.
7. Misc: Screens and identifies the management nodes clicked throughout runtime.
8. Community Profiler: Incorporates the listing of all nodes speaking over Godot’s multiplayer API and the way a lot information every one among them acquired or despatched in the course of the debug session.

This text focuses on tabs 1, 2, 3, 4 and 5. Nonetheless, be at liberty to look at the others utilizing the identical challenge. A few of them, corresponding to Community Profiler gained’t have any fascinating info, although, as the sport doesn’t use the multiplayer API in any level.

Utilizing Breakpoints

After executing the sport, it’s best to have seen that the principle situation is that it’s not possible to destroy the enemy ships. So, logically, there have to be an issue with the perform invoked when damaging the enemy ships — possibly the ships don’t take harm when they need to?

To check if that is true, look at the perform that offers harm to the enemies: open projectile.gd and discover the damage_body perform. The perform code is:

func damage_body(physique: Node2D) -> void:
    # 1
    physique.take_damage(3)
    # 2
    create_explosion() 
    # 3
    queue_free()       

This code does the next:

1. When the bullet collides with the enemy ship, it reduces the ship’s well being by 3 factors;
2. An explosion seems on the purpose the place the collision occurred;
3. The bullet is faraway from reminiscence;

This can be a simple perform, and its logic appears to be appropriate. How can it not be working? Wouldn’t or not it’s nice if there was a means of getting a deeper have a look at how the code is working? That’s the place breakpoints are available, permitting you to halt the code execution and dig deeper to find the issue.

Breakpoints

When analyzing code, the error won’t be apparent simply by trying on the code; you may want to take a look on the code throughout runtime. To do exactly that, you’ll want to make use of breakpoints and watches, which work collectively to help and confirm what the code is doing.

If you outline a breakpoint, Godot is aware of it might want to execute the challenge usually as much as that time. After that, it halts execution and permits you to management how briskly the code ought to execute, and allows you to see which code executes in case of conditionals or loops.

The outline ought to be sort of summary now, however you’ll see that in apply it’s quite simple and helpful!