Files

1456 lines
12 KiB
Plaintext
Raw Permalink Normal View History

Add two tutorial games that build, run in CI, and cannot drift examples/sidescroller and examples/jrpg are complete programs, built with the library and exercised headless by ctest. The chapters quote them with `c excerpt=examples/...` blocks rather than restating the code, so a chapter cannot drift from a program that compiles -- the excerpt check fails the moment the source moves. 34 excerpts in one chapter, 21 in the other. The two are complementary. The sidescroller is the physics tutorial: gravity, a jump, coins, hazards. The JRPG is the content-pipeline tutorial: a town map, NPCs spawned from map objects, four-way per-facing animation, a text box, a follower. Both smoke tests drive real SDL_Events through akgl_controller_handle_event and step the physics clock at a fixed 1/60s rather than sleeping, so a scripted run is deterministic and finishes in under five seconds. Writing them is what turned up most of the defects recorded in the next commit, because a game exercises paths a unit test does not. Each workaround says in the chapter which library gap forced it: - collision is written in a custom movementlogicfunc, because akgl_physics_arcade_collide raises AKERR_API and akgl_physics_simulate never calls collide at all; - the sidescroller cancels the step's own gravity when it blocks downward, because otherwise a quarter-pixel of penetration makes the *horizontal* sweep report blocked and the character walks backwards a tile at a time; - both clear movement_controls_face on every map-spawned actor, because the default facefunc leaves a stopped actor with no facing bit, no sprite, and no draw; - the JRPG's follower gets a renderfunc that nulls obj->parent for the duration of the draw, because a child's offset is counted twice. Assets are CC0 from three Kenney packs, vendored with per-pack licence text, per-file provenance, and the geometry contract in docs/tutorials/assets/README.md. CC0 specifically rather than merely free: a reader who copies a tutorial into their own game inherits no obligation. scripts/fetch_tutorial_assets.sh refreshes them in the shape mkcontrollermappings.sh was fixed into for 0.5.0 -- it checks curl's status, refuses a pack page that does not say CC0, verifies the archive and the staged dimensions, and leaves the tracked bytes untouched on any failure. Both failure paths were tested, and a no-op refresh is byte-identical. Co-Authored-By: Claude Code <noreply@anthropic.com> Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-01 20:59:00 -04:00
{
"compressionlevel": -1,
"height": 15,
"infinite": false,
"layers": [
{
"data": [
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
12,
13,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
2,
3,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
2,
3,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1
],
"height": 15,
"id": 1,
"name": "background",
"opacity": 1,
"type": "tilelayer",
"visible": true,
"width": 40,
"x": 0,
"y": 0
},
{
"data": [
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
28,
29,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
28,
29,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
28,
29,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
28,
29,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
31,
0,
0,
0,
0,
0,
0,
33,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
35,
0,
0,
0,
0,
0,
0,
37,
0,
0,
0,
0,
0,
0,
21,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
23,
0,
0,
0,
21,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
22,
23,
15,
15,
15,
25,
15,
15,
15,
15,
15,
15,
25,
15,
15,
15,
15,
15,
15,
25,
0,
0,
0,
15,
15,
15,
25,
15,
15,
15,
15,
15,
15,
25,
15,
15,
15,
15,
15,
15,
25,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
0,
0,
0,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15,
15
],
"height": 15,
"id": 2,
"name": "terrain",
"opacity": 1,
"type": "tilelayer",
"visible": true,
"width": 40,
"x": 0,
Delete the sidescroller's collision, and let the library do it collision.c was 383 lines that re-implemented akgl_physics_simulate's own arithmetic, because movementlogicfunc runs before gravity, drag and the move and so had to predict where the actor would end up. The whole file goes. What replaces it is three lines in main.c, a shape on the player and the blob, and a `collidable` property on the map's terrain layer -- which also retires SS_TERRAIN_LAYER_ID, a compiled-in layer id that broke whenever somebody reordered layers in Tiled. grounded stays a probe rather than becoming a contact test. A contact says something pushed back this step; grounded asks whether there is a floor to push off, and that stays true through the frame after landing. The blob keeps its own wall and ledge probes for the same reason: the resolver does not say which side of the blob it was pushed from, and says nothing at all about a floor that is missing. The summary line now carries the player's resting position, because exiting 0 was not evidence that collision ran. It reports 136.0,160.0 grounded after 240 autoplay frames -- feet at y=192, flush on the surface of terrain row 12. The tutorial's collision section is rewritten around the library's, keeping the quarter-of-a-pixel story as what a predicting resolver costs. The docs harness learns `json excerpt=`, so the map property the chapter quotes is checked against the map. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01KzBDV2fqgnUAcqCKqKvc71
2026-08-02 07:35:08 -04:00
"y": 0,
"properties": [
{
"name": "collidable",
"type": "bool",
"value": true
}
]
Add two tutorial games that build, run in CI, and cannot drift examples/sidescroller and examples/jrpg are complete programs, built with the library and exercised headless by ctest. The chapters quote them with `c excerpt=examples/...` blocks rather than restating the code, so a chapter cannot drift from a program that compiles -- the excerpt check fails the moment the source moves. 34 excerpts in one chapter, 21 in the other. The two are complementary. The sidescroller is the physics tutorial: gravity, a jump, coins, hazards. The JRPG is the content-pipeline tutorial: a town map, NPCs spawned from map objects, four-way per-facing animation, a text box, a follower. Both smoke tests drive real SDL_Events through akgl_controller_handle_event and step the physics clock at a fixed 1/60s rather than sleeping, so a scripted run is deterministic and finishes in under five seconds. Writing them is what turned up most of the defects recorded in the next commit, because a game exercises paths a unit test does not. Each workaround says in the chapter which library gap forced it: - collision is written in a custom movementlogicfunc, because akgl_physics_arcade_collide raises AKERR_API and akgl_physics_simulate never calls collide at all; - the sidescroller cancels the step's own gravity when it blocks downward, because otherwise a quarter-pixel of penetration makes the *horizontal* sweep report blocked and the character walks backwards a tile at a time; - both clear movement_controls_face on every map-spawned actor, because the default facefunc leaves a stopped actor with no facing bit, no sprite, and no draw; - the JRPG's follower gets a renderfunc that nulls obj->parent for the duration of the draw, because a child's offset is counted twice. Assets are CC0 from three Kenney packs, vendored with per-pack licence text, per-file provenance, and the geometry contract in docs/tutorials/assets/README.md. CC0 specifically rather than merely free: a reader who copies a tutorial into their own game inherits no obligation. scripts/fetch_tutorial_assets.sh refreshes them in the shape mkcontrollermappings.sh was fixed into for 0.5.0 -- it checks curl's status, refuses a pack page that does not say CC0, verifies the archive and the staged dimensions, and leaves the tracked bytes untouched on any failure. Both failure paths were tested, and a no-op refresh is byte-identical. Co-Authored-By: Claude Code <noreply@anthropic.com> Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-01 20:59:00 -04:00
},
{
"draworder": "topdown",
"id": 3,
"name": "actors",
"objects": [
{
"height": 32,
"id": 1,
"name": "player",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_player"
},
{
"name": "state",
"type": "int",
"value": 20
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 32,
"y": 160
},
{
"height": 32,
"id": 2,
"name": "coin1",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_coin"
},
{
"name": "state",
"type": "int",
"value": 16
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 128,
"y": 112
},
{
"height": 32,
"id": 3,
"name": "coin2",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_coin"
},
{
"name": "state",
"type": "int",
"value": 16
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 224,
"y": 80
},
{
"height": 32,
"id": 4,
"name": "coin3",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_coin"
},
{
"name": "state",
"type": "int",
"value": 16
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 352,
"y": 96
},
{
"height": 32,
"id": 5,
"name": "coin4",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_coin"
},
{
"name": "state",
"type": "int",
"value": 16
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 448,
"y": 64
},
{
"height": 32,
"id": 6,
"name": "blob1",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_hazard_blob"
},
{
"name": "state",
"type": "int",
"value": 18
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 400,
"y": 160
},
{
"height": 32,
"id": 7,
"name": "moth1",
"properties": [
{
"name": "character",
"type": "string",
"value": "ss_hazard_moth"
},
{
"name": "state",
"type": "int",
"value": 18
}
],
"rotation": 0,
"type": "actor",
"visible": true,
"width": 32,
"x": 272,
"y": 80
}
],
"opacity": 1,
"type": "objectgroup",
"visible": true,
"x": 0,
"y": 0
}
],
"nextlayerid": 4,
"nextobjectid": 8,
"orientation": "orthogonal",
"properties": [
{
"name": "physics.model",
"type": "string",
"value": "arcade"
},
{
"name": "physics.gravity.y",
"type": "float",
"value": 900.0
},
{
"name": "physics.drag.y",
"type": "float",
"value": 1.5
}
],
"renderorder": "right-down",
"tiledversion": "1.8.2",
"tileheight": 16,
"tilesets": [
{
"columns": 10,
"firstgid": 1,
"image": "tiles.png",
"imageheight": 96,
"imagewidth": 160,
"margin": 0,
"name": "pixel_line_platformer",
"spacing": 0,
"tilecount": 60,
"tileheight": 16,
"tilewidth": 16
}
],
"tilewidth": 16,
"type": "map",
"version": "1.8",
"width": 40
}