Wanna give your GB Studio project some perspective?

A perspective view game on the GameBoy is quite uncommon, especially when using GB Studio. That's precisely why I decided to take it as a challenge and create a mini-game with this element for my submission to GBcompo2023.

Some GameBoy racing games have utilized a perspective view by employing scanline interrupts per line to provide players with a sense of depth. However, my approach is simpler and doesn't require scanline interrupts (at least for the GameBoy Color). You can achieve the desired visual effect without writing an engine library if you're targeting the GameBoy Color.



The image above showcases the raw background image (with some offset and cropping). It consists of three sections: the HUD, the sky (to render the protagonist), and the ground. The HUD section is quite straightforward, just set it to fixed position and it's good to go. As for the sky and ground sections, my current method involves using the window layer for the sky and the background layer for the ground. However, upon further consideration, I realized that I can actually swap them around, using the window layer for the ground and the background layer for the sky. This way, I can achieve the desired effect without relying on an engine library. Now, you might wonder, why does the ground appear to look like moving?



The answer is "palette swapping". It has some pro and con when comparing to scanline interrupt.  While it may be limited to only four frames, it requires less processing power. Additionally, I can draw the ground unevenly to give it a more cartoony appearance. In my use case, palette swapping is sufficient (please note that an engine library is still needed to support GameBoy DMG).



To bring the background to life, I've added some animated looping trees in sides, creating the illusion of the protagonist moving forward. Although they visually blend into the background, the animated trees are actually sprites, whereas the protagonist is comprised of background tiles. I find this fact quite amusing. For your reference, I drew inspiration for this design idea from the chase game in Mickey Mania  (Mickey Mania's "Impossible" 3D Chase - How Was It Done?).

The final aspect to address is the game objects. Due to the GameBoy's lack of hardware scaling support, I had to draw them in multiple sizes. (PS: Simply scaling them in Photoshop is not advisable for pixel art.) The movement is 2D linear to minimize calculations.

And that's how I created the visual aspect of the second mini-game in Kaiju Kai Kai. I hope my experimentation proves helpful to you in creating something entertaining with GB Studio in the future.