Real art in the tutorials (and your own)

Each tutorial ships a bonus_art.py — the finished capstone game re-skinned with real, free CC0 pixel art. They prove the engine’s core idea: art is orthogonal to code. Diff a bonus_art.py against its step8/step9 and almost nothing changed but the bitmaps.

Tutorial	bonus uses	from (CC0)
01-bounce	brick wall = a CC0 brick texture recoloured into the 4 row colours (ball/paddle stay generated)	Kenney Tiny Dungeon
02-starship	ship (pre-rotated 16 frames) + laser bullet	Kenney Pixel Shmup
03-quest	tileset (floor/lava/barrel/brick/door/chest) + hero + slime + coin	Kenney Tiny Dungeon

Run one:

python3 sim/run.py tutorials/03-quest/bonus_art.py --shot /tmp/out.png

The pipeline: any PNG → a picogame sprite

tools/png2picogame.py turns a PNG into a tiny Python module exposing bitmap(pg):

python3 tools/png2picogame.py hero.png -o hero_art.py --frames 8

then in a game:

import hero_art
hero = pg.Sprite(hero_art.bitmap(pg), x, y)        # drop-in replacement for any shp.*()

Options:

• --frames N — the PNG is a horizontal strip of N equal-width frames (left→right).
• --tile WxH — the PNG is a grid of W×H tiles; repacks them into a horizontal atlas (use for grid sheets; output frame count = number of tiles).
• format is auto (PAL8 if ≤256 colours, else RGB565); transparency comes from the PNG’s alpha (alpha ≥128 = opaque); colours are emitted in ST7789 wire order.

Layout rules (so it just works)

• Horizontal strip, equal-width frames. (Grids: use --tile WxH, or in Aseprite export Sheet Type: Horizontal, Trim OFF.)
• Transparency = the alpha channel (one on/off key, no blending). Hard pixel edges; avoid soft/anti-aliased alpha — it quantises badly.
• Tilesets: the engine draws tile value v as frame v, so make frame 0 empty/ transparent and put your tiles at 1, 2, 3… (that’s how bonus_art maps map values to real tiles).
• Rotation: for constant spin, bake rotations into frames (crisper + cheaper than runtime sprite.angle). The Starship ship is the Kenney sprite rotated into 16 frames offline (see how tools/-side scripts build the strip), then ship.frame = angle.

Using your own Aseprite art

File → Export Sprite Sheet → Sheet Type: Horizontal, Trim OFF, Padding 0 → that’s exactly the strip png2picogame wants. Design in Indexed mode with a small palette (or RGBA with a transparent background). Animation Frame Tags can drive frame ranges.

Where to get more (free)

• kenney.nl — everything CC0, no attribution. (We used Pixel Shmup + Tiny Dungeon.)
• Recolouring CC0 art is allowed and often the quickest fix: the Bounce bricks are one grey Tiny Dungeon tile multiplied into 4 colours — texture of real art, palette you want.
• itch.io (CC0 filter), OpenGameArt (filter CC0). Avoid CC-BY-SA / GPL art.
• See the project memory note “picogame art sources” for the full rundown.

Licensing / credits

All bundled art is CC0 (public domain, no attribution required). The source PNGs we used live in assets/kenney/ with assets/kenney/CREDITS.txt. Even for CC0 it’s good manners to keep a credits note when you publish a game.