import { Context } from './context';
import { AbstractObject } from './object';
/**
 * WebGL shader wrapper encapsulating shader creation, compilation, and deletion. A shader can be attached to multiple
 * Programs for linking, and can be deleted if detached from all (linked) programs. The expected default behavior is to
 * create a shader, attach it to programs, and  discard is immediately after all programs are created (linked). If,
 * however, the source of a shader needs to be changed, e.g., for replacements or other modifications, the shader
 * object should be kept and, on change, all programs that have the shader attached have to be invalidated/relinked
 * manually.
 *
 * ```
 * var frag = new gloperate.Shader(context, context.gl.FRAGMENT_SHADER, 'EmptyFragmentShader');
 * var vert = new gloperate.Shader(context, context.gl.VERTEX_SHADER, 'EmptyVertexShader');
 * vert.initialize('void main() { }');
 * frag.initialize('void main() { }');
 *
 * var prog = new gloperate.Program(context, 'EmptyProgram');
 * prog.initialize([frag, vert]);
 * ```
 */
export declare class Shader extends AbstractObject<WebGLShader> {
    /** @see {@link type} */
    protected _type: GLenum;
    /** @see {@link source} */
    protected _source: string;
    /** @see {@link compiled} */
    protected _compiled: boolean;
    /**
     * Map of replacement strings and the value to replace them with.
     */
    protected _replacements: undefined | Map<string, string>;
    /**
     * Object constructor, requires a context and a valid identifier.
     * @param context - Valid context to create the object for.
     * @param type - Either GL_VERTEX_SHADER or GL_FRAGMENT_SHADER.
     * @param identifier - Meaningful name for identification of this instance.
     */
    constructor(context: Context, type: GLenum, identifier?: string);
    /**
     * Creates a shader, sets the shader source, and compiles the shader. If the shader source cannot be compiled, the
     * identifier and an info log are logged to console and the shader object is deleted. Note that a '#version 300 es'
     * is added in case the shader source is compiled in a WebGL2 context.
     * @param source - Shader source.
     * @param compile - Whether or not to compile the shader immediately if a source is provided.
     * @returns - Either a new shader or undefined if compilation failed.
     */
    protected create(source?: string, compile?: boolean): WebGLShader | undefined;
    /**
     * Delete the shader object. This should have the reverse effect of `create`.
     */
    protected delete(): void;
    /**
     * Triggers recompilation of a shader. This is usually used internally automatically, but exposed here for leaky
     * abstraction. It should not be required to invoke this manually in most cases. The shader object is marked as
     * compiled iff the source compiled successfully. Note that invalidation of all programs this shader is attached
     * to needs to be done manually.
     */
    compile(): void;
    /**
     * Adds a search-replacement-pair that is processed every time the shaders is recompiled. Note that recompilation
     * has to be triggered manually. Internally, all replacements are stored as a Map of search and replacement values.
     * Thus, specifying a replacement value overrides an existing search value.
     * @param searchValue - String that is to be searched (all occurrences) and replaced by replace value.
     * @param replaceValue - The value to be used as replacement for all search value occurrences.
     */
    replace(searchValue: string, replaceValue: string): void;
    /**
     * Either VERTEX_SHADER or FRAGMENT_SHADER.
     */
    get type(): GLenum;
    /**
     * Allows to change the shader's source. Note that this will not recompile the shader.
     */
    set source(source: string);
    /**
     * Read access to the shader's source (without replacements applied).
     */
    get source(): string;
    /**
     * Processes all search values and replaces them with the replace value on the source.
     * @returns The source with all replacements applied.
     */
    get sourceWithReplacements(): string;
    /**
     * Read access the the shader's compile status. True if last compilation was successful.
     */
    get compiled(): boolean;
}