d3b69ff867402d2b738a0f774d57ea1b6a543c9a
3 Commits
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66d8670690
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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 Co-Authored-By: Andrew Kesterson <andrew@aklabs.net> |
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f637292eb7
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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 Co-Authored-By: Andrew Kesterson <andrew@aklabs.net> |
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4e7d2cff6c
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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> Co-Authored-By: Andrew Kesterson <andrew@aklabs.net> |
