Debugging Initiatives in Godot | Kodeco

It would 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 enables the developer to identify and clear up points through the a number of growth iterations. That is illustrated by the next pseudocode:

whereas growing == true:
    code
    check
    debug

When growing a sport, nonetheless, there are different points to consider, akin to sport steadiness or verifying behaviors that is likely to be too quick or refined to note throughout gameplay.

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

These are only a few of the questions you may need to reply whereas testing your sport. 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 mission is similar from the Publishing Your Godot Mission 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 could discover what’s flawed with it utilizing the debug instruments. How handy! :]

You possibly can obtain the mission utilizing the Obtain supplies hyperlinks on the high and backside of this text. Be aware that this mission requires Godot 4.3 or newer to run.

The beginning mission 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 effective time to obtain and run the mission to evaluate the way it’s working and see how the bugs affect the sport. The primary challenge you’ll discover is that it’s unattainable 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 need to use to evaluate 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 deal with 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 mission via the Run the mission 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 appropriate of the Output possibility. The next image reveals the debug panel:

On the panel’s high, you’ll be able to see just a few 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 through the debug session. You’ll be taught extra about this tab later on this article.
2. Errors: Reveals the error and warning messages through the sport execution.
3. Profiler: Reveals which code is working 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 exhibiting which code is working and the way a lot time it takes for execution. You’ll be taught extra about this tab later on this article.
5. Displays: Incorporates graphs of sport data, akin 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 potential to evaluate it even after execution.
6. Video RAM: Reveals a listing of sources and the way a lot video RAM they use whereas working, in addition to the grand complete on the high of the panel.
7. Misc: Displays and identifies the management nodes clicked throughout runtime.
8. Community Profiler: Incorporates the record of all nodes speaking over Godot’s multiplayer API and the way a lot knowledge every one among them acquired or despatched through 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 mission. A few of them, akin to 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 is best to have observed that the primary challenge is that it’s unattainable 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;

It is a simple operate, and its logic appears to be appropriate. 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 in, 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.

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