Creating sprites and playing a basic game

rmion

Robert Mion

Posted on March 4, 2023

Creating sprites and playing a basic game

In the last article I inspected each line of the example main.lua file provided in Inside Playdate.

Of particular interest were the lines that referenced images:

local playerImage = gfx.image.new("Images/playerImage")

local backgroundImage = gfx.image.new( "Images/background" )
Enter fullscreen mode Exit fullscreen mode

How do I make images that will display on the Playdate's screen?

What exactly are sprites?

Finding free online sprite-making software

A couple of Google searches and list-based articles later, I found a solution: Piskel

After a few minutes scanning the interface and just drawing silly nonsense, I made this:
Player image in Piskel

I exported as a PNG file to preserve the transparency.

Next, I needed a background image.

Making a background image

The document mentioned that the center of the screen is 200,120.

I take that to mean the screen's pixel grid is 400 x 240.

So, I opened my go-to design tool, Sketch, created an artboard of that size, and used the pencil tool to draw a scrappy landscape:
Background in Sketch

I exported it as a PNG as well.

Compiling and running the game.pdx file

I replaced the contents of my sample game's main.lua file with the one from the documentation.

I ran the compile command.

And I opened the game.pdx file in the Playdate Simulator.

Good news:

  • I saw the player image
  • I could move the player image

Bad news:

  • I didn't see the background image

Mystery solved: line color

  • I went back into Sketch
  • I selected all the lines I just drew
  • Their border color was light gray

That's probably why I didn't see the image: gray became white...or just didn't render!

I updated all lines to be black.

I reloaded the game.pdx file into the Simulator.

No change.

I re-compiled the game.

Reloaded it.

I now saw the background image!

Game running successfully

Short but successful

  • I accomplished my goal: play the game with images I made
  • I learned to check line colors for a 1-bit screen
  • I discovered a great tool for making sprites

More documentation studying, coming up next!

💖 💪 🙅 🚩
rmion
Robert Mion

Posted on March 4, 2023

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