Debugging Tasks in Godot | Kodeco

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

Because of this, most built-in growth environments (IDEs) embody a debugger that enables the developer to identify and clear up points throughout the a number of growth iterations. That is illustrated by the next pseudocode:

whereas growing == true:
    code
    check
    debug

When growing a recreation, nevertheless, there are different points to consider, reminiscent of recreation steadiness or verifying behaviors that may be too quick or delicate to note throughout gameplay.

Give it some thought. You fastidiously crafted your recreation’s problem degree, so that you wish to ensure it’s as much as the problem. However how are you going to rely the variety of enemies in a recreation once they’re shifting round and capturing at you?
You may wish to test the sport steadiness. Is the variety of enemies spawned at a given prompt what you anticipate? Did the power-up add the injury increase you anticipated?

These are only a few of the questions you may wish to reply whereas testing your recreation. 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 Undertaking 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 must discover what’s mistaken with it utilizing the debug instruments. How handy! :]

You’ll be able to obtain the challenge utilizing the Obtain supplies hyperlinks on the prime and backside of this text. Word 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 effective time to obtain and run the challenge to evaluation the way it’s working and spot how the bugs affect the sport. The principle subject you’ll discover is that it’s unimaginable to destroy the enemy ships, though they will destroy your ship, so it’s debugging time!

Overview of the Debug Instruments

Godot has a set of highly effective debug instruments you should use to evaluation 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 means of the Debugger panel on the backside of the display screen, as a result of these are the instruments that collect data when executing the challenge by means of 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 best of the Output possibility. The next image reveals the debug panel:

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

1. Stack hint: Reveals the execution stack, the context and its variables, and permits for controlling how the sport executes throughout the debug session. You’ll be taught extra about this tab later on this article.
2. Errors: Reveals the error and warning messages throughout the recreation execution.
3. Profiler: Reveals which code is operating 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 operating and the way a lot time it takes for execution. You’ll be taught extra about this tab later on this article.
5. Screens: Comprises graphs of recreation data, reminiscent of 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 attainable to evaluation it even after execution.
6. Video RAM: Reveals a listing of sources and the way a lot video RAM they use whereas operating, 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: Comprises the checklist of all nodes speaking over Godot’s multiplayer API and the way a lot information every certainly one of them acquired or despatched throughout 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, reminiscent of Community Profiler received’t have any attention-grabbing data, 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 subject is that it’s unimaginable to destroy the enemy ships. So, logically, there have to be an issue with the perform invoked when damaging the enemy ships — perhaps the ships don’t take injury when they need to?

To check if that is true, study the perform that offers injury 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 it’s nice if there was a manner of getting a deeper take 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.

Whenever 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 lets you management how briskly the code ought to execute, and allows you to see which code executes in case of conditionals or loops.

The outline must be form of summary now, however you’ll see that in follow it’s quite simple and helpful!