@woosh/meep-engine/src/engine/animation/clip/curve_from_track_data_cubic_tangents.js

Pure JavaScript game engine. Fully featured and production ready.

import { Keyframe } from "../curve/Keyframe.js";

/**
 *
 * @param {AnimationCurve} curve
 * @param {number[]} values
 * @param {number[]} times
 * @param {number} component_count
 * @param {number} component_index
 */
export function curve_from_track_data_cubic_tangents(curve, values, times, component_count, component_index) {

    const key_count = times.length;

    for (let k = 0; k < key_count; k++) {
        const component_position = k * component_count;

        // 3 corresponds to 3 parts of a keyframe: inTangent, value, outTangent
        const base_offset = 3 * component_position;

        // Layout of keyframe output values for CUBICSPLINE animations:
        //   [ inTangent_1, splineVertex_1, outTangent_1, inTangent_2, splineVertex_2, ... ]

        const inTangent = values[base_offset + component_index];
        const value = values[base_offset + component_count + component_index];
        const outTangent = values[base_offset + component_count * 2 + component_index];

        const time = times[k];

        curve.add(Keyframe.from(time, value, inTangent, outTangent));
    }

}