Jumper Wire with displayio for PyGamer

Published on 2019-06-24 in PyBadge Hacking.

Over the weekend I sat down and ported the Jumper Wire platformer game to use displayio entirely instead of my stage/ugame libraries.

Here are some thoughts I have from that exercise:

• Since there is no one common library for handling initialization and inputs (like the “ugame” library for stage), there is currently no way to write a portable game — you have to target a particular revision of a particular device — the PyGamer in this case, which uses “gamepadshift” for the buttons, and “analogio” for the joystick. Other devices might use “gampad” or “seesaw” for the buttons and/or joystick, or even come up with something entirely new.

• The refresh rate is fixed and decoupled from the game logic, which results in the sprites moving in a jittery fashion and missing animation frames. Fixing the game logic to the refresh rate would help, but would result on widely varying playing experience depending on the device and version of firmware, as performance varies.

• The removal of “flip_x” attribute forced me to double the number of sprite graphics, and consequently the memory being used up by them, to include flipped versions of practically all of them.

• While the partial screen updates sped up displayio enough to make such a game possible in the first place, the result is still slower on SAMD51 than the same game using stage library on the SAMD21. This alone makes me thing that it’s worth it to keep stage around.

• The analog joystick knob on the PyGamer is horrible — maybe a better version could be 3D-printed.

• Having to pre-commit on a fixed size of the groups is a huge pain — especially when your game creates sprites dynamically (missiles, explosions, drops). Adding them to the group at the right layer is a challenge as well.

• Figuring out how to load a BMP file was a bit of a challenge, and opening the file in the wrong mode stopped me for quite a while.

And finally, here’s the repository with the game: https://github.com/deshipu/jumper-wire-displayio-pygamer