34 lines
1.1 KiB
JavaScript
34 lines
1.1 KiB
JavaScript
'use strict';
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import { SLOPE_FACTOR, VELOCITY_EPS } from './utils';
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const DERIVATIVE_EPS = 0.1;
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export function rubberBandDecay(animation, now, config) {
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'worklet';
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const {
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lastTimestamp,
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startTimestamp,
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current,
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velocity
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} = animation;
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const deltaTime = Math.min(now - lastTimestamp, 64);
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const clampIndex = Math.abs(current - config.clamp[0]) < Math.abs(current - config.clamp[1]) ? 0 : 1;
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let derivative = 0;
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if (current < config.clamp[0] || current > config.clamp[1]) {
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derivative = current - config.clamp[clampIndex];
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}
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const v = velocity * Math.exp(-(1 - config.deceleration) * (now - startTimestamp) * SLOPE_FACTOR) - derivative * config.rubberBandFactor;
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if (Math.abs(derivative) > DERIVATIVE_EPS) {
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animation.springActive = true;
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} else if (animation.springActive) {
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animation.current = config.clamp[clampIndex];
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return true;
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} else if (Math.abs(v) < VELOCITY_EPS) {
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return true;
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}
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animation.current = current + v * config.velocityFactor * deltaTime / 1000;
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animation.velocity = v;
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animation.lastTimestamp = now;
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return false;
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}
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//# sourceMappingURL=rubberBandDecay.js.map
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