import { Game } from '../core';
import { Entity } from '../entity';
/**
 * Internal-use utility type representing a Shader Variable Resolution Function which retrieves a value from the Game
 */
declare type StaticShaderVariableResolver = (game: Game) => Float32Array | number;
/**
 * Internal-use utility type representing a Shader Variable Resolution Function which retrieves a value from an Entity
 */
declare type EntityShaderVariableResolver = (e: Entity) => Float32Array | number;
/**
 * Utility class for automatically retrieving attribute and uniform shader values from Entities, Components and other Game constructs
 *
 * Forms a critical component of the system's rendering approach, where Entities are able to specify their own Shaders. Utilised by the
 *   EntityManager in the construction of Vertex Buffers, and by the WebGLRenderer in the upload of Uniforms
 *
 * Works in conjunction with VertexShader + FragmentShader configuration objects, which specify the names, sizes, types, and variation
 *   patterns of their attributes and uniforms
 *
 * Mappings of <shaderVariableName => ResolutionFunction> are broken into three categories - Attribute, EntityUniform and StaticUniform:
 *   - Attribute - attributes, varying per vertex, to be retrieved from Entities in the construction of Vertex Buffers by the EntityManager
 *     - example: `attribute vec2 a_Position;` - a vertex position, retrieved from an Entity's Model Component
 *
 *   - EntityUniform - uniforms, varying per Entity, to be retrieved from Entities and uploaded once per draw call by the WebGLRenderer
 *     - example: `uniform mat3 u_Transform2D;` - an Entity's Transformation Matrix, retrieved from its Transform Component
 *
 *   - StaticUniform - uniforms, unrelated to Entities, to be retrieved from the Game and uploaded once per render call by the WebGLRenderer
 *     - example: `uniform mat3 u_View2D;` - the 2D View Matrix, retrieved from the Game's World/Camera
 *
 * The mappings built into the class represent the supported set of built-in Attribute/Uniform names which, when used in Shaders, will
 *   automatically be retrieved; thereby also setting out the relationship between a variable name and the Entity/engine data it reflects
 *
 * Allows for the registration of new mappings at application initialisation, facilitating the extension of the system's built-in Shader and
 *   Component library
 *
 * Allows for the overriding of built-in mappings as an explicit choice separate from registration; supporting the augmentation of default
 *   engine functionality but avoiding user error
 *
 * Handles errors in the absence of Resulution Functions for given names, preventing invalid WebGL draws
 *
 * // TODO the information in this class *could* be used to 'verify' an Entity's makeup - that it can be rendered with its designated Shader
 *
 * @see EntityShaderVariableResolver
 * @see StaticShaderVariableResolver
 * @see VertexShader
 * @see FragmentShader
 * @see EntityManager
 * @see WebGLRenderer
 */
export declare class ShaderVariableResolver {
    /**
     * Mappings supporting the automatic resolution of Attributes from Entity Components
     */
    private static readonly ENTITY_ATTRIBUTE_MAPPINGS;
    /**
     * Mappings supporting the automatic resolution of draw-call Uniforms from Entity Components
     */
    private static readonly ENTITY_UNIFORM_MAPPINGS;
    /**
     * Mappings supporting the automatic resolution of render-call Uniforms from Game constructs
     */
    private static readonly STATIC_UNIFORM_MAPPINGS;
    /**
     * Resolve an Attribute value, given its name, from an Entity
     *
     * @param attributeName the name of the attribute to resolve a value for
     * @param entity the Entity to retrieve the value from
     *
     * @returns the resolved Attribute value
     */
    static resolveAttribute(attributeName: string, entity: Entity): Float32Array | number;
    /**
     * Resolve a Uniform value, given its name, from an Entity
     *
     * @param uniformName the name of the uniform to resolve a value for
     * @param entity the Entity to retrieve the value from
     *
     * @returns the resolved Uniform value
     */
    static resolveEntityUniform(uniformName: string, entity: Entity): Float32Array | number;
    /**
     * Resolve a Uniform value, given its name, from the Game
     *
     * @param uniformName the name of the uniform to resolve a value for
     * @param game the Game instance to retrieve the value from
     *
     * @returns the resolved Uniform value
     */
    static resolveStaticUniform(uniformName: string, game: Game): Float32Array | number;
    /**
     * Register a new resolution function for a given unknown Shader Attribute name
     *
     * @param attributeName the name of the Attribute to register
     * @param resolve the resolution function to register
     */
    static registerAttributeResolver(attributeName: string, resolve: EntityShaderVariableResolver): void;
    /**
     * Register a new resolution function for a given unknown Shader Uniform name, where that Uniform varies per Entity
     *
     * @param uniformName the name of the Uniform to register
     * @param resolve the resolution function to register
     */
    static registerEntityUniformResolver(uniformName: string, resolve: EntityShaderVariableResolver): void;
    /**
     * Register a new resolution function for a given unknown Shader Uniform name, where that Uniform is unassocated with any given Entity
     *
     * @param uniformName the name of the Uniform to register
     * @param resolve the resolution function to register
     */
    static registerStaticUniformResolver(uniformName: string, resolve: StaticShaderVariableResolver): void;
    /**
     * Override an existing resolution function for a given known Shader Attribute name
     *
     * @param attributeName the name of the Attribute to override
     * @param resolve the replacement resolution function
     */
    static overrideAttributeResolver(attributeName: string, resolve: EntityShaderVariableResolver): void;
    /**
     * Override an existing resolution function for a given known Shader Uniform name, where that Uniform varies per Entity
     *
     * @param uniformName the name of the Uniform to override
     * @param resolve the replacement resolution function
     */
    static overrideEntityUniformResolver(uniformName: string, resolve: EntityShaderVariableResolver): void;
    /**
     * Override an existing resolution function for a given known Shader Uniform name, where that Uniform is unassocated with any given
     *   Entity
     *
     * @param uniformName the name of the Uniform to override
     * @param resolve the replacement resolution function
     */
    static overrideStaticUniformResolver(uniformName: string, resolve: StaticShaderVariableResolver): void;
}
export {};