Issue #193 asked where friction, bounciness and density of a tile
live. Tiles had a fixed surface (friction 0.5, bounciness 0) and a
collider could not use the outline drawn on a texture frame (#141).
Both gaps are closed here.
- A collider has a fifth shape "Frame collision" with a Frame row.
The frame is picked like a sprite's texture and stored as the
value 'frame'.
- The shape is linked, not copied. Redrawing the outline in the
texture tab changes every collider using that frame, in the editor
and on the next play.
- The frame centre sits on the collider origin, one image pixel is
one unit. The shape turns, scales and mirrors like any other.
- Every outline ring blocks. Each ring is split into convex parts the
same way a polygon is.
- Without a frame, with a whole texture or with a frame that has no
outline, the collider is drawn red as a box and blocks nothing.
- Move, Rapier, raycast, detection, hit test, drawing and footprint
all resolve the frame. At runtime an entity looks the frame up
live in the current project.
- A tile has Friction and Bounciness next to Solid and One-way. The
rows only show when Solid is on. Defaults and mixing rules match
the collider. Density is left out because a tilemap never moves.
- Tilemap cells are grouped by surface as well as by one-way angle.
Ice and stone never merge into one rectangle, and every cell brings
its surface to Move and Rapier.
Findings:
- A tile with a collision scale below 1 is no longer flush with a
neighbour of another surface. It is inset there like at an open
side, the same as next to one-way tiles today.
- A bounce test first measured 0.84. The ball had landed on the hero
at the origin, not on the tile. On the tile it measures 0.993.
Tests:
- ./check.sh: 130 files, 1931 tests, exit 0 (was 129 / 1917).
- 14 new unit tests in tests/core/surface.test.ts. The Move tests run
against the editor run and the physics system.
- 3 new e2e checks: 40l (surface rows follow Solid), 42e (collider
has frame size, a walker climbs the slope in the frame).
- GM_STEPS=1-8,39-43 freshly seeded: ALL PASSED, 376 checks.
- Three counter-probes bite: Move ignores the tile surface (2 fail),
Rapier ignores it (1 fails), frame shape falls back to a box
(5 fail).
- Check sum 1198 is computed (1195 + 3), the full run belongs to CI.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
