Debugging Initiatives in Godot | Kodeco

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

For that reason, most built-in improvement environments (IDEs) embody a debugger that enables 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 creating == true:
    code
    take a look at
    debug

When creating a recreation, nevertheless, there are different points to consider, akin to recreation stability or verifying behaviors that may be too quick or refined to note throughout gameplay.

Give it some thought. You rigorously crafted your recreation’s problem stage, so that you wish to be certain 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 wish 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 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 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 Undertaking 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 should discover what’s incorrect with it utilizing the debug instruments. How handy! :]

You’ll be able to obtain the venture utilizing the Obtain supplies hyperlinks on the prime and backside of this text. Notice 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 information have modified: projectile.gd, enemy_ship.gd, and main_game.gd.

Now is an efficient time to obtain and run the venture to evaluation the way it’s working and see how the bugs affect the sport. The primary problem 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 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 concentrate on the instruments accessible via 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 via the Run the venture button.

Debugger Panel

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

On the panel’s prime, you possibly can 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 study extra about this tab later on this article.
2. Errors: Exhibits the error and warning messages in the course of 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. Displays: Comprises graphs of recreation info, akin 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 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: Displays 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 considered one of them acquired or despatched in the course of 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, akin to Community Profiler received’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 problem is that it’s not possible to destroy the enemy ships. So, logically, there should be an issue with the operate 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 operate that offers injury 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;

This can be a easy operate, 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 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.

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