# all files / src/math/ Frustum.js

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     import Vector3 from './Vector3';
    import BoundingBox from './BoundingBox';
    import Plane from './Plane';

    import glMatrix from '../dep/glmatrix';
    var vec3 = glMatrix.vec3;

    var vec3Set = vec3.set;
    var vec3Copy = vec3.copy;
    var vec3TranformMat4 = vec3.transformMat4;
    var mathMin = Math.min;
    var mathMax = Math.max;
    /**
     * @constructor
     * @alias clay.Frustum
     */
    var Frustum = function() {

        /**
         * Eight planes to enclose the frustum
         * @type {clay.Plane[]}
         */
        this.planes = [];

        for (var i = 0; i < 6; i++) {
            this.planes.push(new Plane());
        }

        /**
         * Bounding box of frustum
         * @type {clay.BoundingBox}
         */
        this.boundingBox = new BoundingBox();

        /**
         * Eight vertices of frustum
         * @type {Float32Array[]}
         */
        this.vertices = [];
        for (var i = 0; i < 8; i++) {
            this.vertices[i] = vec3.fromValues(0, 0, 0);
        }
    };

    Frustum.prototype = {

        // http://web.archive.org/web/20120531231005/http://crazyjoke.free.fr/doc/3D/plane%20extraction.pdf
        /**
         * Set frustum from a projection matrix
         * @param {clay.Matrix4} projectionMatrix
         */
        setFromProjection: function(projectionMatrix) {

            var planes = this.planes;
            var m = projectionMatrix.array;
            var m0 = m[0], m1 = m[1], m2 = m[2], m3 = m[3];
            var m4 = m[4], m5 = m[5], m6 = m[6], m7 = m[7];
            var m8 = m[8], m9 = m[9], m10 = m[10], m11 = m[11];
            var m12 = m[12], m13 = m[13], m14 = m[14], m15 = m[15];

            // Update planes
            vec3Set(planes[0].normal.array, m3 - m0, m7 - m4, m11 - m8);
            planes[0].distance = -(m15 - m12);
            planes[0].normalize();

            vec3Set(planes[1].normal.array, m3 + m0, m7 + m4, m11 + m8);
            planes[1].distance = -(m15 + m12);
            planes[1].normalize();

            vec3Set(planes[2].normal.array, m3 + m1, m7 + m5, m11 + m9);
            planes[2].distance = -(m15 + m13);
            planes[2].normalize();

            vec3Set(planes[3].normal.array, m3 - m1, m7 - m5, m11 - m9);
            planes[3].distance = -(m15 - m13);
            planes[3].normalize();

            vec3Set(planes[4].normal.array, m3 - m2, m7 - m6, m11 - m10);
            planes[4].distance = -(m15 - m14);
            planes[4].normalize();

            vec3Set(planes[5].normal.array, m3 + m2, m7 + m6, m11 + m10);
            planes[5].distance = -(m15 + m14);
            planes[5].normalize();

            // Perspective projection
            var boundingBox = this.boundingBox;
            var vertices = this.vertices;
            if (m15 === 0)  {
                var aspect = m5 / m0;
                var zNear = -m14 / (m10 - 1);
                var zFar = -m14 / (m10 + 1);
                var farY = -zFar / m5;
                var nearY = -zNear / m5;
                // Update bounding box
                boundingBox.min.set(-farY * aspect, -farY, zFar);
                boundingBox.max.set(farY * aspect, farY, zNear);
                // update vertices
                //--- min z
                // min x
                vec3Set(vertices[0], -farY * aspect, -farY, zFar);
                vec3Set(vertices[1], -farY * aspect, farY, zFar);
                // max x
                vec3Set(vertices[2], farY * aspect, -farY, zFar);
                vec3Set(vertices[3], farY * aspect, farY, zFar);
                //-- max z
                vec3Set(vertices[4], -nearY * aspect, -nearY, zNear);
                vec3Set(vertices[5], -nearY * aspect, nearY, zNear);
                vec3Set(vertices[6], nearY * aspect, -nearY, zNear);
                vec3Set(vertices[7], nearY * aspect, nearY, zNear);
            }
            else { // Orthographic projection
                var left = (-1 - m12) / m0;
                var right = (1 - m12) / m0;
                var top = (1 - m13) / m5;
                var bottom = (-1 - m13) / m5;
                var near = (-1 - m14) / m10;
                var far = (1 - m14) / m10;

                boundingBox.min.set(Math.min(left, right), Math.min(bottom, top), Math.min(far, near));
                boundingBox.max.set(Math.max(right, left), Math.max(top, bottom), Math.max(near, far));

                var min = boundingBox.min.array;
                var max = boundingBox.max.array;
                //--- min z
                // min x
                vec3Set(vertices[0], min[0], min[1], min[2]);
                vec3Set(vertices[1], min[0], max[1], min[2]);
                // max x
                vec3Set(vertices[2], max[0], min[1], min[2]);
                vec3Set(vertices[3], max[0], max[1], min[2]);
                //-- max z
                vec3Set(vertices[4], min[0], min[1], max[2]);
                vec3Set(vertices[5], min[0], max[1], max[2]);
                vec3Set(vertices[6], max[0], min[1], max[2]);
                vec3Set(vertices[7], max[0], max[1], max[2]);
            }
        },

        /**
         * Apply a affine transform matrix and set to the given bounding box
         * @function
         * @param {clay.BoundingBox}
         * @param {clay.Matrix4}
         * @return {clay.BoundingBox}
         */
        getTransformedBoundingBox: (function() {

            var tmpVec3 = vec3.create();

            return function(bbox, matrix) {
                var vertices = this.vertices;

                var m4 = matrix.array;
                var min = bbox.min;
                var max = bbox.max;
                var minArr = min.array;
                var maxArr = max.array;
                var v = vertices[0];
                vec3TranformMat4(tmpVec3, v, m4);
                vec3Copy(minArr, tmpVec3);
                vec3Copy(maxArr, tmpVec3);

                for (var i = 1; i < 8; i++) {
                    v = vertices[i];
                    vec3TranformMat4(tmpVec3, v, m4);

                    minArr[0] = mathMin(tmpVec3[0], minArr[0]);
                    minArr[1] = mathMin(tmpVec3[1], minArr[1]);
                    minArr[2] = mathMin(tmpVec3[2], minArr[2]);

                    maxArr[0] = mathMax(tmpVec3[0], maxArr[0]);
                    maxArr[1] = mathMax(tmpVec3[1], maxArr[1]);
                    maxArr[2] = mathMax(tmpVec3[2], maxArr[2]);
                }

                min._dirty = true;
                max._dirty = true;

                return bbox;
            };
        }) ()
    };
    export default Frustum;