import type { TSLFloatNode, TSLMat3Node, TSLNode, TSLUniformNode, TSLUintNode, TSLVec4Node } from '../../types/tsl.js';
/** Scalar/vector/matrix field types supported by the MPM particle struct. */
export type MPMParticleFieldType = 'float' | 'int' | 'uint' | 'vec2' | 'ivec2' | 'uvec2' | 'vec3' | 'ivec3' | 'uvec3' | 'vec4' | 'ivec4' | 'uvec4' | 'mat2' | 'mat3' | 'mat4';
/** One material-owned field appended to the solver's particle struct. */
export interface MPMParticleField {
    /** TSL storage type appended to each particle. */
    type: MPMParticleFieldType;
}
/** Material-owned fields keyed by their runtime struct member names. */
export type MPMParticleFieldMap = Record<string, MPMParticleField>;
/** Narrow particle struct access used by the built-in material models. */
export interface MPMParticleNode {
    /** Read a built-in vector field from the particle struct. */
    get(field: 'position' | 'velocity'): TSLVec4Node;
    /** Read a built-in matrix field from the particle struct. */
    get(field: 'C' | 'F'): TSLMat3Node;
    /** Read a custom material-owned field from the particle struct. */
    get(field: string): TSLNode;
}
/** Particle access supplied to material initialization. */
export interface MPMMaterialParticleContext {
    /** Narrow typed view of the current particle struct. */
    particle: MPMParticleNode;
    /** Current particle index when the calling pass exposes it. */
    index?: TSLUintNode | undefined;
}
/** Particle and transfer values supplied while evaluating material stress. */
export interface MPMMaterialStressContext extends MPMMaterialParticleContext {
    /** Affine particle velocity field. */
    C: TSLMat3Node;
    /** Current particle density. */
    density: TSLFloatNode;
    /** Current solver substep duration. */
    dt: TSLFloatNode;
}
/** Context supplied when a material updates deformation after grid transfer. */
export type MPMMaterialUpdateContext = MPMMaterialStressContext;
/** Six-member runtime contract accepted by `MPMSolver`. */
export interface MPMMaterialModel<TUniforms extends object = object> {
    /** Stable material identifier used by diagnostics and tooling. */
    name: string;
    /** Material-owned fields appended to the particle struct. */
    particleFields: MPMParticleFieldMap;
    /** Mutable material parameters captured by the kernel graph. */
    uniforms: TUniforms;
    /** Initialize material-owned state for one seeded particle. */
    initParticle(context: MPMMaterialParticleContext): void;
    /** Return the material stress contribution for one particle. */
    stress(context: MPMMaterialStressContext): TSLMat3Node;
    /** Update material deformation state after grid-to-particle transfer. */
    updateDeformation(context: MPMMaterialUpdateContext): void;
}
/** Parameters for the built-in pressure-and-viscosity fluid model. */
export interface MPMFluidModelOptions {
    /** Tait pressure stiffness. */
    stiffness?: number | undefined;
    /** Target particle density. */
    restDensity?: number | undefined;
    /** Symmetric affine-velocity viscosity coefficient. */
    viscosity?: number | undefined;
}
/** Mutable TSL uniforms owned by {@link MPMFluidModel}. */
export interface MPMFluidUniforms {
    /** Pressure stiffness uniform. */
    stiffness: TSLUniformNode<'float', number>;
    /** Rest-density uniform. */
    restDensity: TSLUniformNode<'float', number>;
    /** Viscosity uniform. */
    viscosity: TSLUniformNode<'float', number>;
}
/**
 * Gamma=1 Tait fluid material used by the ocean example. Density is carried in
 * particle.velocity.w, leaving the 80-byte std430 particle stride unchanged.
 */
export declare class MPMFluidModel implements MPMMaterialModel<MPMFluidUniforms> {
    /** Stable material identifier. */
    name: 'fluid';
    /** Fluid model adds no fields beyond the core particle layout. */
    particleFields: MPMParticleFieldMap;
    /** Live pressure, density, and viscosity controls. */
    uniforms: MPMFluidUniforms;
    /** Create a fluid material with mutable TSL uniforms. */
    constructor({ stiffness, restDensity, viscosity }?: MPMFluidModelOptions);
    /** Store rest density in the core velocity metadata lane. */
    initParticle({ particle }: MPMMaterialParticleContext): void;
    /** Evaluate pressure and viscosity stress for one particle. */
    stress({ C, density }: MPMMaterialStressContext): TSLMat3Node;
    /** Fluid particles have no persistent deformation state to update. */
    updateDeformation(): void;
    /** Accept the shared material callback signature without changing state. */
    updateDeformation(context: MPMMaterialUpdateContext): void;
}