Debugging Tasks in Godot | Kodeco

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

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

whereas growing == true:
    code
    take a look at
    debug

When growing a recreation, nonetheless, there are different points to consider, corresponding to 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 be certain that it’s as much as the problem. However how will you depend the variety of enemies in a recreation after 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 harm enhance you anticipated?

These are just some of the questions you may wish to reply whereas testing your recreation. That is the place Godot’s debug instruments come in useful, serving to you take a look at and confirm all that.

Getting Began

The instance undertaking is similar from the Publishing Your Godot Challenge to itch.io tutorial. Nonetheless, for this text, the code was modified to boost the gameplay expertise. Sadly, the sport broke within the course of and it’s worthwhile to discover what’s unsuitable with it utilizing the debug instruments. How handy! :]

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

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

Now is an efficient time to obtain and run the undertaking to evaluation the way it’s working and see how the bugs affect the sport. The principle difficulty you’ll discover is that it’s unimaginable 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 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 give attention to the instruments accessible via the Debugger panel on the backside of the display screen, as a result of these are the instruments that collect data when executing the undertaking via the Run the undertaking button.

Debugger Panel

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

On the panel’s prime, you possibly can see just a few 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 throughout the debug session. You’ll study extra about this tab later on this article.
2. Errors: Exhibits the error and warning messages throughout the recreation execution.
3. Profiler: Exhibits which code is working and the way it impacts the sport efficiency. You’ll study extra about this tab later on this article.
4. Visible profiler: Shows a graph exhibiting which code is working and the way a lot time it takes for execution. You’ll study extra about this tab later on this article.
5. Screens: Comprises graphs of recreation data, corresponding to frames per second (fps), reminiscence utilization, scene nodes, and extra. The info 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: Exhibits an inventory of sources 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: Comprises the listing of all nodes speaking over Godot’s multiplayer API and the way a lot information every one among them acquired or despatched throughout the debug session.

This text focuses on tabs 1, 2, 3, 4 and 5. Nonetheless, be happy to look at the others utilizing the identical undertaking. A few of them, corresponding to Community Profiler gained’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 is best to have seen that the primary difficulty is that it’s unimaginable to destroy the enemy ships. So, logically, there have to be an issue with the operate invoked when damaging the enemy ships — perhaps the ships don’t take harm when they need to?

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

It is a easy operate, and its logic appears to be right. How can it not be working? Wouldn’t 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 in, 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 wanting on the code; you may want to take a look on the code throughout runtime. To just do that, you’ll want to make use of breakpoints and watches, which work collectively to help and confirm what the code is doing.

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

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