@woosh/meep-engine/src/core/geom/vec3/v3_displace_in_direction.js

Pure JavaScript game engine. Fully featured and production ready.

/**
 *
 * @param {Vector3} result
 * @param {number} distance
 * @param {number} origin_x
 * @param {number} source_y
 * @param {number} source_z
 * @param {number} direction_x
 * @param {number} direction_y
 * @param {number} direction_z
 * @returns {boolean} true if displaced successfully, false if direction had 0 magnitude
 */
export function v3_displace_in_direction(
    result,
    distance,
    origin_x, source_y, source_z,
    direction_x, direction_y, direction_z
) {

    if (distance === 0) {
        result.set(origin_x, source_y, source_z);
        return true;
    }

    // scale direction to have length equal to distance

    const direction_length_sqr = direction_x * direction_x + direction_y * direction_y + direction_z * direction_z;

    if (direction_length_sqr === 0) {
        // direction vector is zero length, avoid division by zero, clamp to source instead
        result.set(origin_x, source_y, source_z);
        return false;
    }

    const direction_length = Math.sqrt(direction_length_sqr);

    const m = distance / direction_length;

    const x = origin_x + direction_x * m;
    const y = source_y + direction_y * m;
    const z = source_z + direction_z * m;

    result.set(x, y, z);

    return true;
}