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)

Because of this, most built-in growth environments (IDEs) embody a debugger that permits the developer to identify and resolve 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, nonetheless, there are different points to consider, equivalent to recreation steadiness or verifying behaviors that could be too quick or refined to note throughout gameplay.

Give it some thought. You rigorously crafted your recreation’s problem stage, so that you need to make certain it’s as much as the problem. However how will you depend the variety of enemies in a recreation after they’re transferring round and taking pictures at you?
You would possibly need to verify the sport steadiness. Is the variety of enemies spawned at a given on the spot what you count on? Did the power-up add the injury enhance you anticipated?

These are just some of the questions you would possibly need to reply whereas testing your recreation. That is the place Godot’s debug instruments come in useful, serving to you check and confirm all that.

Getting Began

The instance undertaking is similar from the Publishing Your Godot Project 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 it’s essential discover what’s fallacious with it utilizing the debug instruments. How handy! :]

You possibly can obtain the undertaking utilizing the Obtain supplies hyperlinks on the high and backside of this text. Be aware 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 recordsdata have modified: projectile.gd, enemy_ship.gd, and main_game.gd.

Now is an efficient time to obtain and run the undertaking to overview the way it’s working and see how the bugs affect the sport. The principle concern 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 utilize 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, this text will deal with the instruments accessible by the Debugger panel on the backside of the display, as a result of these are the instruments that collect info when executing the undertaking by the Run the undertaking button.

Debugger Panel

The debugger panel, situated on the backside of the display by default, is accessible from the Debugger choice on the backside of the window, to the appropriate of the Output choice. The next image exhibits 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:

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 study extra about this tab later on this article.
Errors: Reveals the error and warning messages throughout the recreation execution.
Profiler: Reveals which code is working and the way it impacts the sport efficiency. You’ll study extra about this tab later on this article.
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.
Displays: Comprises graphs of recreation info, equivalent 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 overview it even after execution.
Video RAM: Reveals a listing of assets and the way a lot video RAM they use whereas working, in addition to the grand whole on the high of the panel.
Misc: Displays and identifies the management nodes clicked throughout runtime.
Community Profiler: Comprises the listing of all nodes speaking over Godot’s multiplayer API and the way a lot knowledge every one in all 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 undertaking. A few of them, equivalent to 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’s best to have seen that the primary concern is that it’s unimaginable to destroy the enemy ships. So, logically, there should be an issue with the operate invoked when damaging the enemy ships — possibly the ships don’t take injury when they need to?

To check if that is true, look at 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:

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

It is a simple operate, and its logic appears to be appropriate. 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, 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 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 needs to be sort of summary now, however you’ll see that in apply it’s quite simple and useful!