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XITRIX
87 lines
3.1 KiB
C++
87 lines
3.1 KiB
C++
//
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// Created by Daniil Vinogradov on 12/01/2024.
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//
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#include <UIScrollViewExtensions/DecelerationTimingParameters.h>
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#include <algorithm>
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#include <cmath>
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namespace NXKit {
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namespace {
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NXFloat decelerationCoefficient(NXFloat decelerationRate) {
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auto clampedRate = std::clamp(decelerationRate, 0.001f, 0.999999f);
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return 1000.0f * std::log(clampedRate);
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}
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NXFloat projectedDistanceAlongTrajectory(NXPoint from, NXPoint to, NXPoint value) {
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auto trajectory = to - from;
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auto trajectoryLength = trajectory.magnitude();
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if (trajectoryLength <= 0) return 0;
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auto normalizedTrajectory = trajectory / trajectoryLength;
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auto offset = value - from;
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auto projection = offset.x * normalizedTrajectory.x + offset.y * normalizedTrajectory.y;
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return std::clamp(projection, 0.0f, trajectoryLength);
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}
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}
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NXPoint DecelerationTimingParameters::destination() const {
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auto dCoeff = decelerationCoefficient(decelerationRate);
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if (!std::isfinite(dCoeff) || dCoeff >= 0) return initialValue;
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return initialValue - initialVelocity / dCoeff;
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}
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float DecelerationTimingParameters::duration() const {
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auto velocityMagnitude = initialVelocity.magnitude();
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if (velocityMagnitude <= 0 || threshold <= 0) return 0;
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auto dCoeff = decelerationCoefficient(decelerationRate);
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if (!std::isfinite(dCoeff) || dCoeff >= 0) return 0;
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auto durationArgument = -dCoeff * threshold / velocityMagnitude;
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if (durationArgument <= 0 || !std::isfinite(durationArgument)) return 0;
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auto result = std::log(durationArgument) / dCoeff;
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if (!std::isfinite(result)) return 0;
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return std::max(0.0f, result);
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}
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NXPoint DecelerationTimingParameters::valueAt(NXFloat time) const {
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auto dCoeff = decelerationCoefficient(decelerationRate);
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if (!std::isfinite(dCoeff) || dCoeff >= 0) return initialValue;
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auto clampedTime = std::max(0.0f, time);
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auto exponentialTerm = std::pow(decelerationRate, float(1000 * clampedTime));
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if (!std::isfinite(exponentialTerm)) return initialValue;
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return initialValue + initialVelocity * (exponentialTerm - 1) / dCoeff;
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}
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float DecelerationTimingParameters::durationTo(NXPoint value) const {
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auto velocityMagnitude = initialVelocity.magnitude();
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if (velocityMagnitude <= 0 || threshold <= 0) return 0;
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if (value.distanceToSegment(initialValue, destination()) >= threshold) { return 0; }
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auto dCoeff = decelerationCoefficient(decelerationRate);
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if (!std::isfinite(dCoeff) || dCoeff >= 0) return 0;
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auto distanceToValue = projectedDistanceAlongTrajectory(initialValue, destination(), value);
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auto durationArgument = 1.0f + dCoeff * distanceToValue / velocityMagnitude;
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if (durationArgument <= 0 || !std::isfinite(durationArgument)) return 0;
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auto result = std::log(durationArgument) / dCoeff;
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if (!std::isfinite(result)) return 0;
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return std::max(0.0f, result);
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}
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NXPoint DecelerationTimingParameters::velocityAt(NXFloat time) const {
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auto clampedTime = std::max(0.0f, time);
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auto exponentialTerm = std::pow(decelerationRate, NXFloat(1000 * clampedTime));
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if (!std::isfinite(exponentialTerm)) return {};
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return initialVelocity * exponentialTerm;
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}
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}
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