import { Nullable } from "types";
import { Camera } from "Cameras";
import { Effect } from "Materials";
import { PostProcess, PostProcessOptions } from "PostProcess";
import { Engine } from "Engine";
import { ToGammaSpace } from "Math";

    /**
     * The extract highlights post process sets all pixels to black except pixels above the specified luminance threshold. Used as the first step for a bloom effect.
     */
    export class ExtractHighlightsPostProcess extends PostProcess {
        /**
         * The luminance threshold, pixels below this value will be set to black.
         */
        public threshold = 0.9;

        /** @hidden */
        public _exposure = 1;
        /**
         * Post process which has the input texture to be used when performing highlight extraction
         * @hidden
         */
        public _inputPostProcess: Nullable<PostProcess> = null;
        constructor(name: string, options: number | PostProcessOptions, camera: Nullable<Camera>, samplingMode?: number, engine?: Engine, reusable?: boolean, textureType: number = Engine.TEXTURETYPE_UNSIGNED_INT, blockCompilation = false) {
            super(name, "extractHighlights", ["threshold", "exposure"], null, options, camera, samplingMode, engine, reusable, null, textureType, undefined, null, blockCompilation);
            this.onApplyObservable.add((effect: Effect) => {
                if (this._inputPostProcess) {
                    effect.setTextureFromPostProcess("textureSampler", this._inputPostProcess);
                }
                effect.setFloat('threshold', Math.pow(this.threshold, ToGammaSpace));
                effect.setFloat('exposure', this._exposure);
            });
        }
    }