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 growth environments (IDEs) embody a debugger that enables the developer to identify and remedy points throughout the a number of growth 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, reminiscent of recreation stability or verifying behaviors that may be too quick or refined to note throughout gameplay.

Give it some thought. You fastidiously crafted your recreation’s problem stage, so that you need to be sure that it’s as much as the problem. However how are you going to depend the variety of enemies in a recreation once they’re shifting round and taking pictures at you?
You may need to test the sport stability. Is the variety of enemies spawned at a given instantaneous what you anticipate? Did the power-up add the injury enhance you anticipated?

These are only a few of the questions you may need 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 venture is identical from the Publishing Your Godot Venture to itch.io tutorial. Nevertheless, for this text, the code was modified to boost the gameplay expertise. Sadly, the sport broke within the course of and you could discover what’s mistaken with it utilizing the debug instruments. How handy! :]

You may obtain the venture utilizing the Obtain supplies hyperlinks on the high and backside of this text. Word that this venture requires Godot 4.3 or newer to run.

The beginning venture 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 venture to overview the way it’s working and spot how the bugs affect the sport. The principle problem you’ll discover is that it’s unattainable 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 overview 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 high of the display screen, this text will give attention to the instruments accessible by way of the Debugger panel on the backside of the display screen, as a result of these are the instruments that collect info when executing the venture by way of the Run the venture 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 proper of the Output possibility. The next image reveals the debug panel:

On the panel’s high, you’ll be able to see a number 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 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 displaying 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. Displays: Incorporates graphs of recreation info, 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 overview it even after execution.
6. Video RAM: Exhibits a listing of sources and the way a lot video RAM they use whereas working, in addition to the grand whole on the high of the panel.
7. Misc: Displays 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 knowledge every one in every of them obtained or despatched throughout the debug session.

This text focuses on tabs 1, 2, 3, 4 and 5. Nevertheless, be at liberty to look at the others utilizing the identical venture. A few of them, reminiscent of Community Profiler received’t have any attention-grabbing info, 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 problem is that it’s unattainable to destroy the enemy ships. So, logically, there should be an issue with the perform invoked when damaging the enemy ships — possibly 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;

It is a simple perform, and its logic appears to be right. How can it not be working? Wouldn’t or not 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 may not 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.

Whenever you outline a breakpoint, Godot is aware of it might want to execute the venture 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 type of summary now, however you’ll see that in apply it’s quite simple and helpful!