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>
Generated figures — do not edit
Every PNG in this directory is output, not an asset. Each one is produced by running
the BASIC listing shown immediately above it in the chapter, through
tools/screenshot.c, and it is checked in only because a reader on the forge has no
build tree to generate it from.
To change a picture, change the listing and regenerate:
cmake --build build-akgl --target docs_screenshots
Editing a PNG here by hand puts the picture out of step with the code it illustrates,
which is the exact failure this arrangement exists to prevent — and the docs_screenshots
test will fail on it, because it re-renders every figure and compares byte for byte.
The tag that ties a figure to its listing is screenshot=NAME in the fence info string,
and MAINTENANCE.md documents it along with size=WxH for a figure that needs a surface
other than 320 by 200. A tagged block with no image here fails docs_examples in both
build configurations, so a figure cannot be added to a chapter and then forgotten.