import type { TSLMat3Node, TSLUniformNode } from '../../types/tsl.cjs';
import type { MPMMaterialModel, MPMMaterialParticleContext, MPMMaterialStressContext, MPMMaterialUpdateContext, MPMParticleFieldMap } from './MPMFluidModel.cjs';
/** Parameters for the fixed-corotated elastic material. */
export interface MPMElasticModelOptions {
    /** Young's modulus controlling elastic stiffness. */
    youngsModulus?: number | undefined;
    /** Poisson ratio controlling transverse deformation. */
    poissonRatio?: number | undefined;
    /** Reference particle volume used by the stress calculation. */
    volume?: number | undefined;
    /** Initial particle density. */
    density?: number | undefined;
}
/** Mutable TSL uniforms derived for {@link MPMElasticModel}. */
export interface MPMElasticUniforms {
    /** First Lamé shear parameter. */
    mu: TSLUniformNode<'float', number>;
    /** Second Lamé parameter. */
    lambda: TSLUniformNode<'float', number>;
    /** Reference particle volume. */
    volume: TSLUniformNode<'float', number>;
    /** Initial particle density. */
    density: TSLUniformNode<'float', number>;
}
/** Material-owned particle fields required for elastic deformation. */
export interface MPMElasticParticleFields extends MPMParticleFieldMap {
    /** Persistent deformation-gradient matrix. */
    F: {
        type: 'mat3';
    };
}
/** Fixed-corotated elastic model proving that solver kernels are material-agnostic. */
export declare class MPMElasticModel implements MPMMaterialModel<MPMElasticUniforms> {
    /** Stable material identifier. */
    name: 'elastic';
    /** Elastic deformation-gradient particle field. */
    particleFields: MPMElasticParticleFields;
    /** Live Lamé, volume, and density controls. */
    uniforms: MPMElasticUniforms;
    /** Create a fixed-corotated material and derive its Lamé parameters. */
    constructor({ youngsModulus, poissonRatio, volume, density }?: MPMElasticModelOptions);
    /** Initialize deformation to identity and store material density. */
    initParticle({ particle }: MPMMaterialParticleContext): void;
    /** Evaluate fixed-corotated elastic stress for one particle. */
    stress({ particle }: MPMMaterialStressContext): TSLMat3Node;
    /** Advance the deformation gradient from the affine velocity field. */
    updateDeformation({ particle, C, dt }: MPMMaterialUpdateContext): void;
}