Marcos Pereira

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Notes

This is where I keep notes for future reference. Entries are sorted alphabetically.

CSS

px vs rem

Generally, rem and em should be used for font size related styles and px for everything else, such as margins or padding.

There’s no consensus on whether to use rem for everything or only for font size related styles (using mainly px otherwise).

Browsers zoom by increasing the size of px, so this decision should only affect users who manually configure a different browser default font size.

For those, it may be better to scale fonts only and keep spacing the same, as otherwise they could simply use the zoom feature.

Email

When setting up email make sure to enable SPF, DKIM, and DMARC to properly authenticate messages. Use https://www.dmarctester.com to test this.

If unable to send email through a third party client for a Google Workspace account, try enabling “Allow per-user outbound gateways” in the admin panel.

General development

Floating point

Key Insights On IEEE 754 Floating Point Numbers

Error accumulation

Avoid updating decimal numbers iteratively, which can accumulate errors. Instead, prefer to calculate values from the underlying constants each time.

This is one of the main concerns of the field of numerical analysis.

Git

Commit without a message

git add -A && git commit --allow-empty-message -m '' && git push

Submodules

Git submodules are a nice way of setting up project dependencies.

Adding

You can add a dependency into a repo by running:

git submodule add --name steamworksnt https://github.com/marcospgp/steamworksnt.git <target-folder>

Including the --name prevents the destination path from being used as the name by default, which can be confusing if the module is moved with git mv later.

If submodules will be used in-editor as part of a Unity project, they should be placed in the Assets folder.

Cloning & updating

To update dependencies or download them after a fresh git clone, use:

git submodule update --init --recursive --merge --remote

Removing

To remove a submodule, use git rm <submodule path> (and not git submodule deinit) in accordance with the docs.

However, also note that:

the Git directory is kept around as it to make it possible to checkout past commits without requiring fetching from another repository. To completely remove a submodule, manually delete $GIT_DIR/modules/<name>/.

$GIT_DIR will usually be the .git folder.

Makefile

MacOS

MacOS ships with an outdated version of make that does not support some functionality such as .ONESHELL.

.ONESHELL and .SHELLFLAGS

Context on using .ONESHELL and .SHELLFLAGS:

# Including the ".ONESHELL" target makes all commands within a target run in the
# same shell, instead of isolating each command into its own subshell.
# This allows us to make use of python virtual environments in a more readable
# way, and may also speed up execution.
# https://www.gnu.org/software/make/manual/html_node/One-Shell.html
.ONESHELL:

# ".ONESHELL" causes make to no longer fail immediately. We restore this
# behavior with the "-e" argument.
# We also set "-o pipefail" and "-u" for added strictness.
# Note that "-c" (the default argument when ".SHELLFLAGS" is not specified) must
# be included, otherwise make will error.
# https://www.gnu.org/software/make/manual/html_node/Choosing-the-Shell.html
.SHELLFLAGS := -c -e -o pipefail -u

NASA’s 10 rules for safe code

https://en.wikipedia.org/wiki/The_Power_of_10:_Rules_for_Developing_Safety-Critical_Code

Shell

My MacOS shell setup:

~/.zshrc configuration:

Windows

Emulate MacOS keyboard shortcuts

To emulate MacOS keyboard shortcuts on Windows, use the PowerToys Keyboard Manager with the following settings:

(note that replacing left alt and left ctrl should be good enough, but to keep things short “left” is omitted from these key names below. “left” on its own means “left arrow key”.)

Remap keys:

Remap shortcuts:

(note that the key remap above applies first, so alt below represents the ctrl key on the keyboard, and vice versa)

Restore switching between windows with alt + tab after key remap:

Restore switching tabs:

Move cursor to start/end of line (does not seem to require additional entries for selecting text with the addition of the shift key):

Move cursor word by word, also selecting text if shift included:

Erase word by word:

Drag text lines up and down:

Note: for win + left/right remap to work, “override windows snap” in PowerToys FancyZones must be disabled, as it overrides that shortcut.

And then because we remapped win + left/right/up/down, we restore that functionality on the ctrl key (which is mapped as alt since we remapped ctrl -> alt and vice versa):

Also restore PowerToys Run with:

Missing:

Hardware

Monitors

VA vs IPS vs OLED

IPS is better. VA has issues with ghosting/black smearing. OLED has issues with pixel burn-in.

Unity game dev

Analyzers

Unity has a guide on enabling analyzers. It works, as the .dlls are added as analyzers to the .csproj file generated by Unity:

<ItemGroup>
  <Analyzer Include="/.../Assets/ErrorProne.Net.CoreAnalyzers.dll" />
  <!-- ... -->
</ItemGroup>

However, while the warnings do show up in VSCode (with the C# dev kit extension), they do not appear in the Unity editor’s console.

Also note that the Unity analyzers are added by default, with the path varying based on the code editor selected under Unity -> preferences -> external tools.

I tried setting up a separate C# project to include valuable analyzers as dependencies and make updating all of them at once easier, but the analyzer .dlls aren’t included in the results of dotnet publish and there’s no simple way to change that.

Animations

Importing

Mixamo

Downloading animations “without skin” prevents wasting memory with unnecessary models. However, the avatar generated by Unity for these won’t work properly. That can be fixed by downloading the default Mixamo character (Y Bot) in T-pose and generating an avatar from it, which can then be used with “without skin” Mixamo animations.

Movement without foot sliding

See How to avoid foot sliding in Unity.

Blender

Settings

Unity interop

Frame rate independence

Everything that runs in Update() (as opposed to FixedUpdate()) should be carefully designed to ensure independence from variations in frame rate.

For example, there is a specific formula for a frame rate independent version of calling lerp (linear interpolation) iteratively.

There is an extensive post about this here.

Ready to use code should be available in the Unity utilities repo.

General optimization

The points below have more importance in the context of frequently run code, such as that in Update().

Comparing distances

The expensive square root operation can be avoided by comparing squared distances.

Exponentiation

When raising a number to an integer exponent, direct multiplication (x * x) is more efficient than calling a function such as MathF.Pow() which accepts any real number as exponent.

Microsoft’s recommendations

See Microsoft’s mixed reality performance recommendations for Unity.

Inspector

Textures

It is often useful to generate textures for debugging code visually through the inspector.

To view a texture through the inspector, assign it to a public or [SerializeField] field.

Then generate the texture with the following logic.

var tex = new Texture2D(width, width, TextureFormat.RGBA32, mipChain: false);

for (int i = 0; i < width; i++)
{
    for (int j = 0; j < width; j++)
    {
        tex.SetPixel(
            i,
            j,
            Color.Lerp(Color.black, Color.white, VoronoiNoise.Get(i, j, 30f, 1234L))
        );
    }
}

tex.Apply();

Calling Apply() is required for the texture to appear right away, otherwise an update has to be triggered by changing something on the inspector (such as its anisotropic filtering level).

LODs

Based on https://medium.com/@jasonbooth_86226/when-to-make-lods-c3109c35b802

Mathf vs MathF

UnityEngine.Mathf relies on System.Math, which runs computations on the double type.

System.MathF does computations on the single/float32 type.

The difference may be small however since CPUs generally handle 64bit math better than GPUs.

Multithreading

Awaitable vs Task

Unity introduced Awaitable in version 2023.1, which essentially is a modernization of the Coroutine API (which handles things like waiting for the next frame) to make it compatible with async/await in C#.

The new Awaitable can also handle multithreading with explicit switching between main and background threads using await Awaitable.MainThreadAsync() and await Awaitable.BackgroundThreadAsync().

However, BackgroundThreadAsync appears to be a mere wrapper around Task.Run(), thus with no advantages when it comes to allocating Task objects.

In addition to this, a previously existing issue where pending tasks continue running even after exiting/entering play mode in the Unity editor remains:

Unity doesn’t automatically stop code running in the background when you exit Play mode.

To get around this, I had implemented a SafeTask wrapper as a replacement for Task.Run() (no other Task API functionality is replaced), which still makes sense to continue using:

Relevant links:

General tips

Order of preference for concurrency management mechanisms:

  1. Task model
  2. Concurrent (thread safe) collections
  3. Interlocked
  4. lock
  5. volatile (avoid this for being more obscure and harder to reason about than the Interlocked class)
  6. Lower level synchronization primitives (Mutex, Semaphore, …)

Optimization tips:

NuGet dependencies

With no official NuGet support in Unity at time of writing, one can set up NuGet dependencies through a separate C# project.

There are two other options worth mentioning:

These are the steps to set up dependencies through a standalone C# project:

  1. mkdir NuGetDependencies && cd NuGetDependencies
  2. Run dot.

    Where “NuGetDependencies” is the destination folder. Feel free to modify this, or omit to create a project in the current directory

    We target .NET Standard 2.1 according to Unity compatibility.

    Feel free to delete any .cs files generated automatically, as we won’t need to write any code.

  3. dotnet new gitignore
  4. Add dependencies with dotnet add package <package name> --version <version> (can be copied from NuGet website directly)
  5. Build with dotnet publish (debug configuration is the default). Note we don’t use dotnet build, which doesn’t include dependency .dlls in build files.
  6. Copy the files in ./bin/Debug/netstandard2.1/publish/ to somewhere in the Unity project’s Assets folder, such as Assets/NuGetDependencies/

Procedural mesh generation

Call MarkDynamic on meshes that are updated frequently at runtime.

Project set up

These are things to think about when starting a new project, which can also be worth revisiting once in a while. Generally high-leverage settings with poor defaults or quick fixes for common issues.

Color banding

Fix color banding by checking “enable dithering” in the camera inspector. I only tested this in URP.

Editorconfig

Create a symlink from the project’s root to the .editorconfig file in the Unity Utilities repo, which should be installed as a git submodule in the Assets folder.

Git submodules

Set up dependencies on other repos by installing them as git submodules under the Assets folder.

An example would be the Unity utilities repo: https://github.com/marcospgp/unity-utilities

Mono vs IL2CPP

Decide between Mono or IL2CPP.

Generally, IL2CPP should be better as it can have better performance than Mono, although it may complicate mod creation (although hacking would also become more difficult accordingly).

IL2CPP can improve performance across a variety of platforms, but the need to include machine code in built applications increases both the build time and the size of the final built application.

Shaders

Shader Graph

Hiding properties from inspector

Before version 2023.3.0a11, Shader Graph properties not marked as “Exposed” simply don’t work unless initialized in code. The expected behavior would be to simply hide the property from the material inspector.

There is more info about this issue in this thread.