module BABYLON {
    /**
     * Post process which applies a refractin texture
     * @see https://doc.babylonjs.com/how_to/how_to_use_postprocesses#refraction
     */
    export class RefractionPostProcess extends PostProcess {
        private _refTexture: Texture;
        private _ownRefractionTexture = true;

        /**
         * Gets or sets the refraction texture
         * Please note that you are responsible for disposing the texture if you set it manually
         */
        public get refractionTexture(): Texture {
            return this._refTexture;
        }

        public set refractionTexture(value: Texture) {
            if (this._refTexture && this._ownRefractionTexture) {
                this._refTexture.dispose();
            }

            this._refTexture = value;
            this._ownRefractionTexture = false;
        }
        
        /**
         * Initializes the RefractionPostProcess
         * @see https://doc.babylonjs.com/how_to/how_to_use_postprocesses#refraction
         * @param name The name of the effect.
         * @param refractionTextureUrl Url of the refraction texture to use
         * @param color the base color of the refraction (used to taint the rendering)
         * @param depth simulated refraction depth
         * @param colorLevel the coefficient of the base color (0 to remove base color tainting)
         * @param camera The camera to apply the render pass to.
         * @param options The required width/height ratio to downsize to before computing the render pass.
         * @param samplingMode The sampling mode to be used when computing the pass. (default: 0)
         * @param engine The engine which the post process will be applied. (default: current engine)
         * @param reusable If the post process can be reused on the same frame. (default: false)
         */
        constructor(
            name: string, 
            refractionTextureUrl: string, 
            /** the base color of the refraction (used to taint the rendering) */
            public color: Color3, 
            /** simulated refraction depth */
            public depth: number, 
            /** the coefficient of the base color (0 to remove base color tainting) */
            public colorLevel: number, 
            options: number | PostProcessOptions, 
            camera: Camera, 
            samplingMode?: number, 
            engine?: Engine, 
            reusable?: boolean
        ) {
            super(name, "refraction", ["baseColor", "depth", "colorLevel"], ["refractionSampler"], options, camera, samplingMode, engine, reusable);

            this.onActivateObservable.add((cam: Camera) => {
                this._refTexture = this._refTexture || new Texture(refractionTextureUrl, cam.getScene());
            });

            this.onApplyObservable.add((effect: Effect) => {
                effect.setColor3("baseColor", this.color);
                effect.setFloat("depth", this.depth);
                effect.setFloat("colorLevel", this.colorLevel);

                effect.setTexture("refractionSampler", this._refTexture);
            });
        }

        // Methods
        /**
         * Disposes of the post process
         * @param camera Camera to dispose post process on
         */
        public dispose(camera: Camera): void {
            if (this._refTexture && this._ownRefractionTexture) {
                this._refTexture.dispose();
                (<any>this._refTexture) = null;
            }

            super.dispose(camera);
        }
    }
}