10 Commits

Author	SHA1	Message	Date
Andrew Kesterson	802bbcc17a	Collide sprites with rectangles that are not sprites ... `SOLID id, x1, y1, x2, y2` registers static collision geometry; `SOLID id` retires one and a bare `SOLID` retires them all, the way `TRAP`, `COLLISION` and `DCLOSE` all read absence. `COLLISION 2` and `BUMP(2)` stop being refused and mean *sprite met static geometry*. **This is the thing eight sprite slots made impossible.** A wall of bricks wants sixty, so until now a program could only collide with one by doing the arithmetic itself against its own array -- which is exactly what both breakout listings do, at about two hundred lines between them. A rectangle costs no sprite slot. The id is the **program's own number**, 1 to 64, not a minted handle. That is the whole trick for "which brick did I hit": the id comes back out again, so a wall built as `SOLID I#, ...` maps onto `B#(I#)` with no lookup, and retiring a broken brick is `SOLID I#`. `COLLISION 2` was refused with "sprite-to-background collision needs the screen read back every frame", which was true of the question a C128 asks -- a sprite against the bitmap's set pixels. `SOLID` gives this interpreter a background made of rectangles instead, which is the same question in a form it can answer. Same move `SPRSAV` made when it learned to take an image path. `AKBASIC_INTERRUPT_BACKGROUND` has been sitting in the interrupt table commented "COLLISION 2 -- sprite met background; refused" the whole time. Its accumulator is separate, so a sprite hitting a wall never sets a bit in `BUMP(1)`. **There is no `akgl_CollisionWorld` here, and that is deliberate.** libakgl's uniform grid keeps its cell heads, cell size and origin in file-scope statics, so it is one index per process -- and `akgl_collision_world_init()` ends in a `reset()` that memsets those heads *and* calls `akgl_heap_init_collision_cells()`. An interpreter embedded in a game with its own collision world would have destroyed every registration that game had made, on the first `SOLID` a script ran. So the geometry is indexed by an ordinary array here and pairs go straight to `akgl_collision_test()`, which needs no world. At sixty-four rectangles that is the right answer anyway; libakgl's own numbers put a naive sweep at 0.7% of a frame at sixty-four objects. **The scan now short-circuits when nothing has moved**, and that is what makes any of it affordable. Its inputs are the sprites' boxes, which slots are collidable, and the static geometry; if none changed the answer cannot have. A frame runs one full scan and 255 cached ones. Eight sprites against sixty-four rectangles is five hundred and twelve tests -- fine once a frame, ruinous 256 times. The benchmark was rewritten to say which path it is timing, because with the cache in place a loop that only calls the scan measures the short circuit and nothing else. Breakout now costs 590.6 ns for its one full scan plus 255 cached at 40.0, which is 10.8 us against a 1.19 ms frame -- **0.91%, less than the 2.0% it cost before any of this work**, with static geometry and contacts added on top. `NEW` retires the rectangles, where it cannot undefine a sprite pattern: there *is* an entry point for this one, so leaving them would be a choice, and the wrong one -- a rectangle is invisible, so one left behind by a deleted program is an unexplainable collision in the next. `CLR` leaves them alone. `tests/sprite_verbs.c` gains the whole second path against the mock and its `COLLISION 2` case is rewritten: it pinned the refusal, and now pins that type 2 arms its own handler without disturbing type 1's. `tests/akgl_backends.c` gains the end-to-end version, including a full sixty-four-rectangle wall so the proxy budget is exercised at its ceiling and the pool has to come back intact, and the sixty-fifth refused by name. A bare `SOLID` needed `akbasic_parse_optional_arglist` rather than `akbasic_parse_arglist`, which `DCLOSE` already uses for the same shape. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL	2026-08-02 10:25:35 -04:00
Andrew Kesterson	f005b88980	Let a program say what part of a sprite collides ... `SPRHIT n, kind [,x1, y1, x2, y2]` gives a sprite a collision shape: a box, a circle inscribed in it, or a capsule. `RSPHIT(n, f)` reads it back in SPRHIT's own argument order, the way RSPRITE and RSPPOS already do, and needs no device because it answers from interpreter state. The rectangle is two corners measured from the sprite's top-left, in device pixels -- the same `x1, y1, x2, y2` that `BOX` and `SSHAPE` take. A dialect with two spellings for a rectangle is one nobody can write from memory. Omit it and the shape fits whatever the picture turned out to be, which is what a sprite loaded from a file needs: `SPRSAV "ship.png", 1` takes the image's own size and the program never learns what that was. **A sprite nobody has shaped collides with its whole frame, expansion bits included, exactly as before.** That is a promise rather than a convenience, and it has its own test: the same two sprites in the same two places, once with no SPRHIT and once with a four-pixel box, reporting a collision and then not. Named SPRHIT rather than SPRSHAPE because "shape" already means "a region SSHAPE saved" in this dialect, in this very chapter -- `SPRSAV A$, 1` takes one -- and a reader who typed `SPRSHAPE A$, 1` would have had every reason to. Both names, and RSPHIT, were grepped against every label in docs/, examples/ and both corpora first: a bare word is a label here, so a verb and a label share one namespace and taking a name a checked-in listing already uses would break it silently. `SPRHIT n, 0` takes a sprite out of collision while leaving it on the screen -- the ghost, the flashing invulnerable player, the pickup already taken. Hiding it with `SPRITE n, 0` stops it colliding too, and is what you want when it should not be seen either. The circle answers the complaint chapter 8 already ships a figure of. That figure shows two discs whose *boxes* touch at a corner while the artwork is nowhere near, and `BUMP(1)` reporting a collision; two `SPRHIT n, 2` and it stops. The test asserts both halves so the figure's caption stays true. `tests/verbs_table.c` caught RSPHIT filed after RSPPOS rather than before it, which is the sorted-table test doing exactly the job it exists for. Docs: a new section in chapter 8, rows in the verb and function references in alphabetical order, and chapter 13's "collision is by bounding box" becomes "collision is by shape" with the addition named. 111 with akgl, 110 without, and the artwork breakout still runs clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL	2026-08-02 10:01:33 -04:00
Andrew Kesterson	f06c53110d	Answer sprite collision through libakgl's narrowphase ... `spr_collisions()` computed axis-aligned overlaps itself, because at libakgl 0.7.0 there was nothing to delegate to: `akgl_collide_rectangles()` has a documented corner-containment defect and the physics backend's `collide` slot raised "Not implemented". 0.8.0 brought a real narrowphase, and this moves onto it. The mask is bit-identical and every test from the previous commit passes **unmodified**, which was the gate this stage had to clear -- including the two that were written to be hard to satisfy. Edge-to-edge is still not a collision, so a tile-aligned program is unaffected. The cross-shaped overlap is still reported, which is the one that could have regressed: it is the case `akgl_collide_rectangles()` gets wrong and the reason the hand-written loop existed, and `akgl_collision_test()`'s box path gets it right. What it buys is the contact -- a normal, a penetration depth and a point -- which four comparisons cannot produce. Nothing consumes it yet; that is the next commit. It is here now because the mask and the contact come out of the same test, and computing them in two places would be two things to keep in step. **The first attempt was ten times slower and the benchmark caught it.** Syncing all eight proxies and running the narrowphase on all twenty-eight pairs measured 984 ns a scan against 96 ns for the loop it replaced -- 21% of a frame at 256 scans a frame -- to produce a mask that was bit-identical and a contact that was thrown away. Two changes fixed it, and both are what a broad phase *is* rather than workarounds for a slow library: - **Reject on the bounding boxes first.** The four comparisons that were always here now decide which pairs are worth an exact answer. The narrowphase still decides the bit -- the box test only says "maybe", which will matter the moment a shape is not the whole frame. - **Do not sync a proxy that has not moved.** The scan runs at the top of every interpreter step and a sprite moves at most once in that time, so almost every sync would rewrite a proxy with what it already holds. Compared against the last synced rectangle rather than flagged by the verbs, because a host game can move a BASIC sprite through the actor registry and a flag would miss that. Measured after: 54.9 ns at eight sprites spread out, which is *faster* than the 96.3 ns it replaced -- boxes are now built eight times a scan instead of fifty-six. The number that matters is the new benchmark row for the arrangement `examples/breakout/sprites/breakout.bas` actually has, which is 211.8 ns, or 4.5% of a frame. That game reaches it because two of its eight sprites are the screen -- a captured HUD strip and a captured play field -- so the field's box covers everything and those pairs can never be rejected. Roughly double the old cost, for contacts. Recorded in MAINTENANCE.md with the two synthetic extremes either side of it as a bracket. The eight proxies are claimed once at init and held, so exhaustion of the pool shared with an embedding host is an initialization failure that names the pool rather than a collision scan refusing halfway through somebody's game. The shape is built before the proxy is spawned from it and the acquire sits adjacent to the initialize, which are two traps libakgl hit itself and documents. `tests/akgl_backends.c` now tears the sprite backend down between cases. It never did, and got away with it while init claimed nothing; eight proxies apiece across twenty cases is a hundred and sixty against a pool of a hundred and twenty-eight. A host releases what it took, and so does the harness. Both games run forty seconds headless with no error line. 111 with akgl, 110 without. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL	2026-08-02 09:48:11 -04:00
Andrew Kesterson	d61e352f36	Test the collision scan, and measure what it costs ... `spr_collisions()` had no test. `tests/sprite_verbs.c` drives the collision path end to end but through a mock backend, so the real overlap arithmetic in `src/sprite_akgl.c` could have changed what `BUMP(1)` reports for every program in existence and the suite would still have printed 110/110. That gap is closed here, before anything touches the arithmetic, so that there is a *before* to compare an *after* against. Six cases against the real akgl backend: nothing defined, two sprites overlapping, edge-to-edge, a hidden sprite, and the x-expand bit doubling the box that collides rather than only the one that draws. Edge-to-edge earns its place -- the test is a strict `<`, a tile-aligned program puts sprites there constantly, and a replacement answering "touching" instead of "overlapping" would change every one of them silently. **The seventh is the cross-shaped overlap**, and it is the one to watch. A tall thin sprite crossing a short wide one overlaps without either rectangle holding a corner of the other; `akgl_collide_rectangles()` is documented as answering "no" there, which is why `src/sprite_akgl.c` does the four comparisons itself rather than calling it. Two further assertions stop that test passing by accident: each sprite is moved clear along the axis it is supposed to be short on, so a sprite that came out the wrong size fails rather than quietly reporting an ordinary overlap. `tests/collision_perf.c` answers the question nobody had measured. The service runs at the top of every interpreter *step* and the frontend takes 256 steps per rendered frame, so a busy program scans up to 256 times a frame over sprites that have not moved. At RelWithDebInfo, scale 10, best of 5: the scan is 96.3 ns at eight overlapping sprites and 19.4 ns at none, against a rendered frame of 1.17 ms. **256 scans is 24.7 us, or 2.1% of a frame, in the pathological case, and 0.42% for a program with no sprites.** So the per-step cadence stays. It is what makes a collision report describe where the sprites have just been moved to rather than where they were, and 2% of a frame in a case no real program reaches is not worth changing when a handler fires for every program that already works. The numbers and that conclusion are in `MAINTENANCE.md` so it does not get re-argued. The benchmark borrows libakgl's `benchutil.h` by include path rather than copying it, the way the fixture font is already borrowed, and is labelled `perf` so `ctest -LE perf` can leave it out. It runs at scale 1 in the ordinary suite -- 1.2 seconds -- because a benchmark nothing ever builds is a benchmark that rots. Both suites green: 111 with akgl, 110 without. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL	2026-08-02 09:25:22 -04:00
Andrew Kesterson	a1dcfcacf3	Land a character written past a short row's terminator ... A grid row is a NUL-terminated string, and `putchar_at()` wrote the character, advanced and terminated -- so `CHAR 1, 40, 1, "#"` on an otherwise empty row stored the `#` at column 40 with `text[1][0]` still `'\0'`, and the render loop, which stops at the terminator, drew nothing at all. The silent nothing is the trap. The write succeeded, the cursor moved, the stdout mirror showed the character, and only the window stayed blank -- so the program looked right everywhere except where it mattered. The documented truncation on the way *back* is fine and is unaffected. `putchar_at()` now fills the gap with spaces before storing. **Padded there rather than in `sink_moveto()`**, which TODO.md proposed: this way `moveto` stays read-only -- the objection that entry raised against its own suggestion -- and a row is only ever padded when a character actually arrives. The pad fills from the terminator rather than replacing it. The buffer is not cleared between rows, so replacing only the terminator would expose the tail of whatever longer row used to be there: writing "ABCDEFGHIJ", truncating it to "ABCX", then writing at column 7 must give "ABCX Z" and not "ABCX FGZ". tests/akgl_backends.c asserts all three cases, and the middle one keeps the truncation pinned. TODO.md section 6 item 32, struck. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-02 00:13:42 -04:00
Andrew Kesterson	3415c9aec6	Take libakgl 0.5.0 and rename every symbol it namespaced ... 0.5.0 gives every exported symbol the akgl_ prefix, which is the first libakgl release to break this project's source rather than only its ABI. The soname goes to libakgl.so.0.5 and include/akbasic/akgl.h asserts the floor. What moved here: akgl_render_bind2d is akgl_render_2d_bind, akgl_sprite_sheet_coords_for_frame is akgl_spritesheet_coords_for_frame, the renderer, camera and window globals carry the prefix, and _akgl_renderer and _akgl_camera are akgl_default_renderer and akgl_default_camera. The renames were applied by site rather than by pattern, because renderer is also a parameter name in src/sprite_akgl.c and a struct member throughout src/frontend_akgl.c -- a substitution would have rewritten both without a word. That is the same trap upstream describes hitting, and it is worth knowing that the defect behind the rename was not cosmetic: an exported global called renderer collided with a test's own variable, the executable's definition preempted the library's, and every texture load in that suite failed while the suite passed. 0.5.0 also fixes libakgl defect 26, which was one of the two reasons src/sprite_akgl.c installs its own renderfunc: akgl_actor_render took its destination height from the sprite's width, drawing a 24x21 Commodore sprite as a 24x24 square. The renderfunc stays, because the other reason has not moved -- an actor carries one scalar scale and SPRITE has separate x- and y-expand bits -- but the comments and TODO.md deviation 40 no longer claim a defect that is fixed. Every documentation figure re-renders byte-identical under the new library, which is what says the sprite and drawing paths did not move underneath them. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-01 08:01:43 -04:00
Andrew Kesterson	5c5bf63356	Draw into the whole window, not its top-left 320x200 ... The graphics verbs documented a coordinate transform that did not exist. With SCALE off a coordinate went straight to akgl_draw_* as a pixel address, so an 800x600 window drew a C128 listing into its corner and left the rest unused -- while the chapter said coordinates were 320x200 and stretching to fit was the host's business. akbasic_GraphicsBackend gains a size entry point, require_graphics() asks it before every verb that draws so a resized window is honoured between two statements, and 320x200 becomes the fallback for a backend that leaves it NULL. It is the record's one optional member, so a host written against the old header keeps the behaviour it had. SCALE now maps onto the device, and RGR(1)/RGR(2) report the drawing surface so a program can use a window whose size it did not choose. RGR(0) is BASIC 7.0's own field, the GRAPHIC mode. SCALE also mapped xmax onto the width rather than onto the last pixel, so SCALE 1, 319, 199 followed by DRAW 1, 319, 199 drew nothing at all -- one pixel past the surface. Fixed in the same line, because it is what makes "SCALE gives a C128 listing the whole window" true rather than nearly true. The akgl test renders against a 128x128 target, deliberately smaller than the old constants: a SCALE still dividing by them misses it entirely rather than landing somewhere plausible. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-01 07:35:20 -04:00
Andrew Kesterson	9845e77a5c	Finish the language: every remaining verb group, and the defects that blocked them ... Closes groups A, C, D, E, F, H and J of TODO.md section 4, plus RESTORE and RENUMBER, and closes section 6 -- all seventeen reference defects. Seven of those turned out to have been fixed or never ported and nobody had written it down; the audit records the evidence for each. Two of the seventeen were real. math_plus mutated its left operand when the operand was mutable, so A# + 1 could modify A#; it was gated on FOR/NEXT coverage because NEXT relied on the mutation, so tests/for_next.c came first and NEXT now writes the counter back itself. And the binary operators summed both numeric fields of their right operand, which no BASIC program can reach -- that one needed a test written against the value API. Writing the tests turned up eight defects nobody had listed. Seven are fixed: IF A = 2 THEN was a parse error; only == worked IF ... AND ... was a parse error, because a condition parsed as one relation IF A = 1 OR B = 2 THEN was silently always false, and so was IF A THEN EXIT before any NEXT restarted the program and exhausted the variable pool READ never found a DATA line above it, and swallowed the lines between PRINT 2 + 2 at the prompt was filed as program text instead of answering a short read discarded its bytes, so COPY produced empty files every verb taking an argument list said "peek() returned nil token!" on none The eighth is not fixed and cannot be quietly: a FOR whose step overshoots runs its body one extra time, and FOR I = 1 TO 1 runs it zero times. The two errors cancel for a step of 1, which is why neither was noticed. Correcting them changes the expected output of a checked-in acceptance file, and tests/reference/README.md forbids editing one to suit this interpreter. It is tests/for_semantics.c in AKBASIC_KNOWN_FAILING_TESTS, asserting the correct contract, and TODO.md items 19 and 20. Sprites are real libakgl actors with a renderfunc of their own, because akgl_actor_render draws every sprite square and an actor has no per-axis scale. Both are filed upstream. SPRSAV takes an image file, an SSHAPE handle or a 63-element integer array -- a string here cannot hold a zero byte. Verbs that need hardware that does not exist are refused by name with the reason rather than faked: SYS, HEADER, COLLECT, BACKUP, BOOT, FILTER, and DIRECTORY, which is refused for a missing libakstdlib wrapper filed upstream. 94 tests in the default build, 93 with SDL, 94 under ASan and UBSan, doxygen clean. The Go acceptance corpus stayed green throughout. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 21:50:37 -04:00
Andrew Kesterson	fca9ad4a89	Consume libakgl 0.3.0: every workaround deleted, two capabilities gained ... 0.3.0 closed all ten API gaps this port had filed. The four workarounds go with them: the CMake block that declared libakgl's vendored dependencies by hand, the akgl/actor.h include in three files, and the six vtable pointers assigned by hand in two more, now akgl_render_bind2d(). Two gaps were capabilities rather than inconveniences, and both are now real: The line editor takes the composed UTF-8 text the ring carries in preference to the keycode, so shifted characters, keyboard layouts, compose keys and dead keys all work. A double quote can be typed, which means a BASIC string literal can be typed -- the sharp end of the old limitation. Letters are no longer folded to upper case. SOUND's dir/min/step reach akgl_audio_sweep instead of being refused. dir 3 sweeps once rather than oscillating and TODO.md section 5 says so. A backend with no sweep still refuses the swept note and plays the held one. The adaptors now carry an AKGL_VERSION_AT_LEAST(0, 3, 0) floor, verified by temporarily demanding 0.4.0 and watching it fire. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 13:25:14 -04:00
Andrew Kesterson	4fc763efb3	Wire the sink and the three devices to libakgl ... src/sink_akgl.c, src/graphics_akgl.c, src/audio_akgl.c and src/input_akgl.c, in the akbasic_akgl target, which is the only thing here that links SDL. -DAKBASIC_WITH_AKGL=ON had never been configured in this repository before, and it now builds and passes. The sink is what section 3 has been waiting on. Its character grid comes from akgl_text_measure(font, "A", &w, &h), the direct equivalent of the reference's font.SizeUTF8("A") and the call that did not exist until 42b60f7. Wrapping is done on the character grid rather than by handing SDL_ttf a wraplength, because the cursor has to land somewhere definite: a program that PRINTs a long string and then PRINTs again expects the second to start on the row after the first ended, and only the code that placed the characters knows which row that is. tests/akgl_backends.c draws into a 128x128 software renderer under the dummy video driver and reads the pixels back -- the pattern deps/libakgl/tests/draw.c established, which needs no display and no offscreen harness. It asserts the seam rather than libakgl's own behaviour: a BASIC line in, a lit pixel of the right colour out. Four things in libakgl had to be worked around to get here. All four are commented at their site with "filed upstream" and recorded in TODO.md section 3: - An embedded libakgl requires SDL, SDL_image, SDL_mixer, SDL_ttf and jansson to be *installed*. It builds its own vendored copies only when it is top-level, and they are sitting right there in deps/libakgl/deps. Every lookup is guarded with if(NOT TARGET ...), so this adds those five subdirectories before add_subdirectory(deps/libakgl) -- the same trick and the same ordering requirement akerror::akerror and akstdlib::akstdlib already need. - akgl/controller.h does not compile on its own: it declares handlers taking an akgl_Actor * and includes nothing that declares the type. - There is no way to attach a 2D backend to a renderer you already have. akgl_render_init2d() installs the vtable but also creates its own window and writes the camera global, so it belongs to the akgl_game_init() path -- which is exactly the path an embedding host is not on. The test assigns the six pointers by hand. - akgl_text_rendertextat() segfaults on a backend whose vtable is empty; it reaches through renderer->draw_texture without checking it. Same class of defect 42b60f7's own commit added a draw test for. The sink's readline reports end of input rather than reading: a drawn text layer is not a source of lines, and INPUT through one wants a line editor built on the keystroke ring. EOF rather than an error is the contract sink.h states, so INPUT already handles it. That editor is the next piece of work there. 70/70 core ctest with no SDL on the include path, 71/71 with the akgl suite, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 08:46:53 -04:00