import freezeObject from '../Core/freezeObject.js';
import WebGLConstants from '../Core/WebGLConstants.js';

    /**
     * Determines how two pixels' values are combined.
     *
     * @exports BlendEquation
     */
    var BlendEquation = {
        /**
         * Pixel values are added componentwise.  This is used in additive blending for translucency.
         *
         * @type {Number}
         * @constant
         */
        ADD : WebGLConstants.FUNC_ADD,

        /**
         * Pixel values are subtracted componentwise (source - destination).  This is used in alpha blending for translucency.
         *
         * @type {Number}
         * @constant
         */
        SUBTRACT : WebGLConstants.FUNC_SUBTRACT,

        /**
         * Pixel values are subtracted componentwise (destination - source).
         *
         * @type {Number}
         * @constant
         */
        REVERSE_SUBTRACT : WebGLConstants.FUNC_REVERSE_SUBTRACT,

        /**
         * Pixel values are given to the minimum function (min(source, destination)).
         *
         * This equation operates on each pixel color component.
         *
         * @type {Number}
         * @constant
         */
        MIN : WebGLConstants.MIN,

        /**
         * Pixel values are given to the maximum function (max(source, destination)).
         *
         * This equation operates on each pixel color component.
         *
         * @type {Number}
         * @constant
         */
        MAX : WebGLConstants.MAX
    };
export default freezeObject(BlendEquation);