mirror of
https://github.com/lhns/steam-frame-nix.git
synced 2026-10-06 01:00:13 +02:00
Pierre Kisters
0699d0f532
Steam's UpdateTouchState counts the event's `touches` per key: that count is the pressed highlight (rgLayoutTouchCount -> Touched) and where the long press (Backspace repeat, accents) starts. The touch-start event left the new touch out of `touches`, like a touchend; now it is in, as in a DOM touchstart (tracker.js touchEvent, with a test against a model of Steam's handlers).
79 lines
3.6 KiB
JavaScript
79 lines
3.6 KiB
JavaScript
// tracker.js: when a controller's tip touches a key (vr-keyboard-touch.nix;
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// argument of keyboard-patch.js, tested by tests/tracker.test.mjs).
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// Evaluates to { VERSION, DEFAULTS, createTracker, touchEvent }.
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//
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// createTracker(opts): one hand. update(sample, tMs) with the tip relative
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// to the keyboard ({ u, v, d } of vr-keyboard-controllers' geometry.js:
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// keyboard widths from the top left corner, m behind the surface; null: no
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// pose / keyboard unusable) returns null or an event { phase, u, v }:
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// down the tip passed through the surface (at `depth` behind it) from
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// the front between two samples, at u, v (interpolated) inside the
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// keyboard, not faster than maxStep per sample, minIntervalMs
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// after the last release;
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// up it came back out: release m back from its deepest point, or in
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// front of the surface by arm; u, v where it is now;
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// cancel the sample was null while down.
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// A press needs the tip in front by arm (re-armed) since the last one, so
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// tracking jitter at the surface can't repeat it, and the tip coming from
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// behind or around the keyboard never presses.
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//
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// touchEvent(t, others, starting): what Steam's HandleTouchStart /
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// HandleTouchEnd read, shaped like a DOM TouchEvent: changedTouches [t];
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// touches: the touches down, with t at its start, without it at its end.
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// Steam's UpdateTouchState counts `touches` per key for the pressed
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// highlight and starts the long press (Backspace repeat, accents) there.
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(() => {
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const VERSION = 2;
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const DEFAULTS = {
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depth: 0, // m behind the drawn surface where a touch registers
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arm: 0.005, // m in front of it to re-arm
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release: 0.01, // m back from the deepest point to release
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maxV: 0.5, // keyboard height bound (widths; the page is ~0.33)
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maxStep: 0.08, // m per sample; more is a tracking jump, not a touch
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minIntervalMs: 60, // release -> next press
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};
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function createTracker(opts = {}) {
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const O = { ...DEFAULTS, ...opts };
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let prev = null, armed = false, pressed = false, deepest = 0, releasedAt = -Infinity;
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const inside = (u, v) => u >= 0 && u <= 1 && v >= 0 && v <= O.maxV;
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function update(s, t) {
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if (!s) {
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prev = null; armed = false;
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if (!pressed) return null;
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pressed = false; releasedAt = t;
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return { phase: 'cancel' };
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}
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const d = s.d - O.depth;
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let ev = null;
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if (pressed) {
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deepest = Math.max(deepest, d);
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if (d < deepest - O.release || d < -O.arm) {
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pressed = false; armed = false; releasedAt = t;
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ev = { phase: 'up', u: s.u, v: s.v };
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}
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} else if (armed && prev && prev.d < 0 && d >= 0) {
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armed = false;
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const f = prev.d / (prev.d - d); // where the segment meets the surface
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const u = prev.u + f * (s.u - prev.u), v = prev.v + f * (s.v - prev.v);
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if (inside(u, v) && d - prev.d <= O.maxStep && t - releasedAt >= O.minIntervalMs) {
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pressed = true; deepest = d;
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ev = { phase: 'down', u, v };
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}
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} else if (d < -O.arm) armed = true;
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else if (d >= 0) armed = false;
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prev = { u: s.u, v: s.v, d };
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return ev;
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}
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return { update, get pressed() { return pressed; } };
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}
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const touchEvent = (t, others, starting) => ({
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type: starting ? 'touchstart' : 'touchend', target: t.target, changedTouches: [t],
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touches: starting ? [...others, t] : [...others],
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preventDefault() {}, stopPropagation() {},
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});
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return { VERSION, DEFAULTS, createTracker, touchEvent };
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})()
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