A camera that follows smoothly stands between pixels most of the time,
and pixel art then wanders between them. The new camera switch draws
what the camera shows on the game view's own grid, while positions in
the model keep their fractions.
- `Pixel perfect` is a camera row, off by default. It works at every
fixed game scale and at Auto, but not at Fit and not in the Scene
tab, where one works with the fractions.
- The grid has one step per device pixel of a world unit. At 100% that
is whole units, at 500% fifths. The view carries it (`View.grid`),
so no view draws with the grid of another.
- The view looks from a point that puts the world's origin on a whole
device pixel (`lookFrom`). This also covers odd camera sizes and
views that cut the picture to an odd size.
- Sprites, texts and tilemaps snap their top left corner when they are
unturned, so an odd size lands on whole pixels too. A turned object
snaps its pivot (`snapPlacement` in `pixelGrid.ts`).
- Under a camera shader the picture is taken the same way, and the
objects in it use the picture's grid. With Camera pixels that is one
step per camera pixel.
- An overlay camera has its own switch and snaps only while the main
picture is at a fixed scale.
- Particles are drawn where they are.
- New test hook `__gm.gameDrawnRect(id)` reads where a sprite's picture
is drawn, which `gameRect` (the model's) cannot tell.
Found: the e2e fixture at 300% drew the crate at y 205.5 device pixels
without moving the camera, because the view cut to an odd height puts
its centre on half a pixel. With the switch on it is at 206.
Tests:
- Gate: 237 files, 3587 tests (+10 in pixel-grid.test.ts)
- e2e 2,3: ALL PASSED, 75 checks (+1, 3j)
- Counter-checks: without the origin snap 3 unit tests fail, with the
centre snapped instead of the corner 2 fail
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
