Entry 354

"A HUD scale: each HUD part shrinks toward its own corner"

2026-10-02uirender

Filescrates/piney-fieldui/src/spr.rscrates/piney-fieldui/src/disp.rscrates/piney-fieldui/src/render.rscrates/piney-desktop/src/sprite.rscrates/piney-desktop/src/layers.rscrates/piney-game/src/area.rscrates/piney-game/src/main.rs

Not the game's. The user expected render scale to make the HUD smaller, as a PC game's does at a higher resolution. Render scale adds detail (350) to a picture that always fills the window, so a separate hud_scale (0.5 to 1; console hud_scale, --hud-scale) now does it.

Anchors

One sprite queue can carry several HUD parts. MenuFont, for one, holds the party panels' HP and SP digits and the target window's numbers in a single send. So an anchor has to come from the code that draws each part, not from the queue. Each packet now carries spr::Anchor, a point per axis in the menu's 512 x 448 space, or none. Disp sets it on every sprite before each part:

• party panels: bottom left;
• target window and new-mail mark: top left;
• bracelet gauge: top right;
• battle band: its height alone, toward the top;
• battle announcement: the centre.

Everything else keeps its size: the menus, the message window, world-anchored marks (enemy bars, the target cursor, balloons, damage numbers) and the dim. The renderer scales a packet's position (its offset folded in) and its size about the anchor. At 1 it leaves the packet untouched, so the game's frames, and the 65 harness tests, are unchanged.

The minimap and two seams

The field's minimap (piney_world::map) draws whole into the layers. Layers::mark and map_since let area.rs shrink just its commands toward the top right: vertices, scissors (the inclusive ends widened to whole pixels) and texture coordinates.

At 0.6 a light line crossed the map. 0.5 and 0.75 were clean, and the line also showed at render scale 1. A dump of the map's primitives found it. The terrain is four tiles, and each stops 1/16 pixel short of the next (the top tile ends at 121.625, the bottom one starts at 121.6875). On whole-pixel positions that gap never covers a pixel's centre. Shrunk to fractional ones it can, and the sky showed through. A shrunk sprite's far edges are now taken from the next tile's start (+1/16 before scaling), so neighbouring tiles share one edge. Clean at 0.55, 0.6 and 0.8.

A shrunk cell's texture coordinates are pulled in by half a texel (Sprite::uv_inset, sprite::inset_uv). A bilinear sample at a fractional edge then stays inside its cell of the atlas.

the_hud_scale_shrinks_the_panels_into_their_corner (piney-fieldui) checks the frame at 0.5: the same primitives in the same order, every panel primitive half as wide and moved toward the corner, and the frame back to the game's at 1. A field shot at render scale 2 with HUD scale 1.0 and 0.6 shows the panels in the bottom left and the map in the top right.