/**
 * skin-math — minimal column-major 4x4 matrix helpers for the native character
 * render path. Pure math, zero GPU, zero foreign-engine deps — headless-testable.
 *
 * Column-major convention matches the rest of the native render path
 * (`native-render/draw-spec.ts` composeTRS, `native-render/scene-render.ts` mul4):
 * element (row r, col c) is stored at index c*4 + r; translation lives in m[12..14].
 *
 * @module character-render
 */
export type Mat4 = Float32Array;
export type Vec3 = {
    x: number;
    y: number;
    z: number;
};
export type Quat = {
    x: number;
    y: number;
    z: number;
    w: number;
};
export declare const IDENTITY4: () => Mat4;
/** Column-major multiply: out = a * b. */
export declare function multiply(a: Mat4, b: Mat4): Mat4;
/** Chain-multiply left→right: out = m0 * m1 * … * mn. */
export declare function multiplyAll(...mats: Mat4[]): Mat4;
export declare function fromTranslation(x: number, y: number, z: number): Mat4;
/** Rotation matrix from a unit quaternion (column-major). */
export declare function fromQuat(q: Quat): Mat4;
/** Compose translation · rotation (T * R). */
export declare function fromRotationTranslation(q: Quat, t: Vec3): Mat4;
/** Unit quaternion from axis (need not be normalized) + angle (radians). */
export declare function quatFromAxisAngle(ax: number, ay: number, az: number, rad: number): Quat;
export declare const IDENTITY_QUAT: Quat;
/** Hamilton product a·b (apply b, then a — same convention as matrix multiply). */
export declare function quatMultiply(a: Quat, b: Quat): Quat;
/** Transform a point (w=1) by a column-major matrix. */
export declare function transformPoint(m: Mat4, x: number, y: number, z: number): Vec3;
/** Translation component of a column-major matrix. */
export declare function getTranslation(m: Mat4): Vec3;
/** Full 4x4 inverse (gl-matrix adjugate method). Returns identity if singular. */
export declare function invert(a: Mat4): Mat4;
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