Debugging Tasks 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 growth environments (IDEs) embrace a debugger that permits 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 recreation, nonetheless, there are different points to consider, comparable to recreation steadiness or verifying behaviors that could be too quick or refined to note throughout gameplay.

Give it some thought. You fastidiously crafted your recreation’s problem degree, so that you need to make sure that it’s as much as the problem. However how will you rely the variety of enemies in a recreation once they’re shifting round and taking pictures at you?
You would possibly need to examine the sport steadiness. Is the variety of enemies spawned at a given on the spot what you anticipate? 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 turn out to be useful, serving to you check and confirm all that.

Getting Began

The instance venture is similar from the Publishing Your Godot Undertaking 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 you must discover what’s flawed 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. 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 recordsdata have modified: projectile.gd, enemy_ship.gd, and main_game.gd.

Now is an efficient time to obtain and run the venture to assessment the way it’s working and spot how the bugs affect the sport. The primary situation you’ll discover is that it’s inconceivable 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 use to assessment 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 give attention to the instruments accessible via the Debugger panel on the backside of the display, 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 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 possibly can see a couple of 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 study extra about this tab later on this article.
2. Errors: Reveals the error and warning messages through the recreation execution.
3. 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.
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: Incorporates graphs of recreation info, comparable 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 potential to assessment it even after execution.
6. 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.
7. Misc: Screens and identifies the management nodes clicked throughout runtime.
8. Community Profiler: Incorporates the checklist of all nodes speaking over Godot’s multiplayer API and the way a lot knowledge every one among them obtained or despatched through the debug session.

This text focuses on tabs 1, 2, 3, 4 and 5. Nonetheless, be at liberty to look at the others utilizing the identical venture. A few of them, comparable to Community Profiler gained’t have any fascinating info, although, as the sport doesn’t use the multiplayer API in any level.

Utilizing Breakpoints

After executing the sport, you must have observed that the principle situation is that it’s inconceivable 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, look at 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 appropriate. How can it not be working? Wouldn’t it’s nice if there was a method 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 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.

If 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 must be sort of summary now, however you’ll see that in apply it’s quite simple and helpful!