Andrew Kesterson
cb0e2d0800
Two complete games in `examples/breakout/`, both 100% BASIC: `characters/` draws its wall in the text grid with two `DATA` sprites for the ball and paddle, and `sprites/` loads CC0 artwork and captures its whole screen with `SSHAPE`/`SPRSAV`. They take opposite shapes for reasons that are entirely this interpreter's, which is what the chapters are for. `docs/17-tutorial-breakout.md` and `docs/18-tutorial-breakout-artwork.md` build each one a step at a time, and end in a checklist of the rules a real program runs into: create every name before the loop starts, write a text row whole, loop with `GOTO` rather than `DO`, put the float on the left. Every trap is a runnable block with its own output rather than a claim -- the value pool dying at four thousand names, the skipped `BEGIN` block that breaks its caller's `RETURN`, `SSHAPE` ignoring a subscript, `READ`'s single cursor. Five figures, generated from the listings beside them by `docs_screenshots`, and a `breakout_art` setup so the ones that load artwork load the example's own. The character game's wall cannot be photographed -- the screenshot host omits the text layer on purpose -- so it is shown as compared output instead. `docs/07-sound.md` never said `SOUND`'s frequency is a SID register value rather than hertz, which both games depend on. It says so now, with the conversion from `src/audio_tables.c:84`. `TODO.md` gains the thirteen defects the two games turned up -- §6 items 30 to 33 and all of §9 -- each with a reduction that fits on a screen, the file and line of the cause, and what a fix would touch. Verified: `docs_examples` passes in both build configurations, `docs_screenshots --check` re-renders all thirteen figures and byte-compares them, the full 109-test suite passes in both builds, every quoted fragment was checked to appear verbatim in the listing it came from, and every relative link and anchor resolves. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Where this art came from
Every PNG in this directory is from Kenney's Puzzle Pack 1, released into the public
domain under Creative Commons Zero.
License.txt is the pack's own licence file, copied here unedited.
- Source: https://kenney.nl/assets/puzzle-pack-1
- Downloaded: 2026-08-01,
kenney_puzzle-pack-1.zip - Author: Kenney (https://www.kenney.nl)
- Licence: CC0 1.0. Crediting is not required; it is here because it should be.
The files are the pack's PNG/Default/ versions, byte for byte — nothing is resized,
recoloured or re-encoded, so the checksum of any of them still matches the distributed
archive.
| File | Size | Used for |
|---|---|---|
paddleBlu.png |
104x24 | the player's paddle |
paddleRed.png |
104x24 | the second paddle, from the CATCHER powerup |
ballBlue.png |
22x22 | the ball |
ballGrey.png |
22x22 | the extra balls from MULTIBALL |
element_red_polygon_glossy.png |
48x46 | the EXPAND powerup |
element_yellow_polygon_glossy.png |
48x46 | the MULTIBALL powerup |
element_green_polygon_glossy.png |
48x46 | the SLOW powerup |
element_blue_polygon_glossy.png |
48x46 | the STICKY powerup |
element_purple_polygon_glossy.png |
48x46 | the CATCHER powerup |
The pack's PNG/Double/ versions are twice these sizes and are the wrong scale for an
800x600 field. SPRITE's x- and y-expand bits would double them again, which is the only
scaling this interpreter has — there is no way to make a sprite smaller — so the
Default set is the one that fits.
Everything else on screen — the bricks, the walls, the HUD lettering, the title — is drawn
by the program with DRAW and BOX. See README-sprites.md for why only eight things in
this game can be made of artwork.