Tom Boullay
65 lines
1.9 KiB
TypeScript
65 lines
1.9 KiB
TypeScript
import type {
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HandTrackingHand,
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HandTrackingLandmark,
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} from "@/types/handTracking/handTracking";
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function lerp(previous: number, next: number, factor: number): number {
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return previous * (1 - factor) + next * factor;
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}
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function smoothLandmark(
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previous: HandTrackingLandmark,
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next: HandTrackingLandmark,
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factor: number,
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): HandTrackingLandmark {
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return {
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x: lerp(previous.x, next.x, factor),
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y: lerp(previous.y, next.y, factor),
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z: lerp(previous.z, next.z, factor),
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};
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}
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function smoothHand(
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previous: HandTrackingHand,
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next: HandTrackingHand,
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factor: number,
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): HandTrackingHand {
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return {
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...next,
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x: lerp(previous.x, next.x, factor),
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y: lerp(previous.y, next.y, factor),
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z: lerp(previous.z, next.z, factor),
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landmarks: next.landmarks.map((landmark, index) => {
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const previousLandmark = previous.landmarks[index];
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if (!previousLandmark) return landmark;
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return smoothLandmark(previousLandmark, landmark, factor);
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}),
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};
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}
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/**
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* Apply an exponential moving average to the landmark positions of each
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* detected hand. MediaPipe lands per-frame positions with noticeable
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* jitter (especially at ~10fps), and feeding those raw values into the
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* scene makes both the glove rig and any grabbed object tremble.
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*
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* `factor` is the weight given to the latest sample (0 = previous frame
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* only, 1 = no smoothing). Hands are matched between frames by
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* handedness so left/right don't bleed into each other.
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*/
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export function smoothHands(
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previousHands: HandTrackingHand[],
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nextHands: HandTrackingHand[],
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factor: number,
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): HandTrackingHand[] {
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if (factor >= 1) return nextHands;
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return nextHands.map((next) => {
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const previous = previousHands.find(
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(candidate) => candidate.handedness === next.handedness,
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);
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if (!previous) return next;
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return smoothHand(previous, next, factor);
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});
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}
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