A silly project for Halloween

Halloween Night Sky over the French Countryside

While Halloween never reached the same level of popularity in France as Christmas, I’ve always had a preference for the former over the latter. In the past, we would decorate our countryside home with glowing, carved pumpkins, creating a truly unique nighttime landscape.

A typical carved pumpkin we used to make

Although my childhood and the house I grew up in are now distant memories, the emotions and the ambiance of Halloween continue to resonate in me as the holiday comes every year.

The project idea

Recently, I had some interest learning Bevy, a trendy game engine written in Rust. Although it is usable not only for games, its ECS (Entities-Components-Systems) makes it really easy to get started with 2D and 3D real-time projects. With Bevy in my mind, and Halloween coming by, I wanted to create a small related project to learn more about it.

At first, I didn’t have a specific plan in mind, but I decided to draw a simple ghost using Bevy’s built-in shapes. As I worked on it, I noticed that I was making a similar mistake to what I had done when I reproduced Atari’s Space Race game, where I initially drew everything with basic shapes and then had to meticulously organize them in code.

Atari Space Race game reproduction

Instead, I decided to save development time by using a sprite approach, so I went with a Jack Skellington’s head PNG. Scrolling through other Bevy examples, I found one showcasing how to scale a 3D object over time. Seeing this, I thought, “What if the image scaled with a music’s loudness?” The idea is simple: as the music gets louder, the image grows larger and as the music quiets down, the image shrinks.

Final result

The source code is available on GitHub.

What I learned

• ECS concept
• Bevy main framework
• minimp3 and the mp3 format

What I struggled with

The following points are to be taken with a grain of salt as I am not a Bevy nor a WASM expert. There are probably easy ways to come around these issues, but due to time constraints I did not want to bother too much.

• Building the project in WASM and making it running in the current web page was part of my initial goal, but I could not compile to that target with minimp3.
• I did not understand how to easily specify dynamic path (for example through a CLI option) for resources as Bevy assumes that everything is in the assets folder.
• I am not sure how to make the image scale in a more esthetic way. I thought about using a low-pass filter on the music loudness level, but I did not have enough time to implement.