/** A clip to bake: its name and length in seconds. */
export interface BoneTextureClipInput {
    name: string;
    duration: number;
}
/** One baked clip's rows in a {@link BoneTextureLayout}. */
export interface BoneTextureClip {
    name: string;
    /** First texture row of the clip. */
    startFrame: number;
    /** Rows baked for the clip, first and last pose included. */
    frameCount: number;
    duration: number;
}
/**
 * Where every bone matrix of every baked frame lives in a vertex-animation texture: one row per
 * frame, four RGBA texels (matrix columns) per bone. Plain data, so a baked crowd can be cached,
 * shipped or checked in a test without a renderer.
 */
export interface BoneTextureLayout {
    boneCount: number;
    fps: number;
    width: number;
    height: number;
    clips: BoneTextureClip[];
}
/** Inputs for {@link planBoneTexture}. */
export interface BoneTextureInput {
    boneCount: number;
    clips: readonly BoneTextureClipInput[];
    /** Baked samples per second. Default 30. */
    fps?: number;
    /** Largest texture side the target GPU accepts. Default 4096. */
    maxTextureSize?: number;
}
/**
 * Plans a bone-matrix texture for a rig's clips. Throws when the rig or the clip set does not fit
 * `maxTextureSize`; lower `fps` or bake fewer clips.
 *
 * @capability animation bake many clips of a rig into one bone-matrix texture for instanced crowds
 */
export declare function planBoneTexture(input: BoneTextureInput): BoneTextureLayout;
/** Two texture rows around a playback time and the blend between them. */
export interface BoneTextureSample {
    rowA: number;
    rowB: number;
    t: number;
}
/**
 * Finds the baked rows around `time` in a clip, wrapping when `loop` and holding the last pose
 * otherwise. This is the CPU mirror of the crowd shader's lookup.
 *
 * @capability animation look up the baked frames and blend for a crowd member's playback time
 */
export declare function sampleBoneTexture(clip: BoneTextureClip, fps: number, time: number, loop: boolean, out?: BoneTextureSample): BoneTextureSample;