Matrix3DUtil

import flash.geom.Matrix3D;
import flash.geom.Orientation3D;
import flash.geom.Vector3D;

public class Matrix3DUnils {
    private static var _raw : Vector.<Number> = new Vector.<Number>(16, true);
    private static var _toRad : Number = 0.0174532925199433;
    private static var _toAng : Vector3D = 57.2957795130823;
    private static var _vector : Vector3D = new Vector3D();
    private static var _right : Vector3D = new Vector3D();
    private static var _up : Vector3D = new Vector3D();
    private static var _dir : Vector3D = new Vector3D();
    private static var _scale : Vector3D = new Vector3D();
    private static var _pos : Vector3D = new Vector3D();
    private static var _x : Number;
    private static var _y : Number;
    private static var _z : Number;

    // 4x4矩阵里面第一列就是右方方向
    public static function getRight(m : Matrix3D, out : Vector3D = null) : Vector3D {
        if (out == null) {
            out = new Vector3D();
        }
        m.copyColumnTo(0, out);
        return out;
    }

    public static function getUp(m : Matrix3D, out : Vector3D = null) : Vector3D {
        if (out == null) {
            out = new Vector3D();
        }
        m.copyColumnTo(1, out); // 第二列是上方方向
        return out
    }

    public static function getDir(m : Matrix3D, out : Vector3D = null) : Vector3D {
        if (out == null) {
            out = new Vector3D();
        }
        m.copyColumnTo(2, out); // 第三列是前方方向
        return out
    }

    public static function setOrientation(m : Matrix3D, dir : Vector3D, at : Vector3D = null, up : Vector3D = null, smooth : Number = 1) : void
    {
        getScale(m, _scale);

        if (up == null) {
            if ((dir.x == 0) && (Math.abs(dir.y) == 1) && (dir.z == 0)) {
                up = Vector3D.Z_AXIS;
            } else {
                up = Vector3D.Y_AXIS;
            }
        }
        dir.normalize();

        var rVec : Vector3D = up.crossProduct(dir);
        rVec.normalize();

        var uVec : Vector3D = dir.crossProduct(rVec);
        rVec.scaleBy(_scale.x);
        uVec.scaleBy(_scale.y);
        dir.scaleBy(_scale.z);

        setVectors(m, rVec, uVec, dir);
    }

    public static function setVectors(m : Matrix3D, right: Vector3D, up : Vector3D, dir : Vector3D) : void {
        right.w = 0;
        up.w = 0;
        dir.w = 0;
        m.copyColumnFrom(0, right);
        m.copyColumnFrom(1, up);
        m.copyColumnFrom(2, dir);
    }

    public static function lookAt(m : Matrix3D, x : Number, y : Number, z : Number, up : Vector3D = null, smooth : Number = 1) : void {
        m.copyColumnTo(3, _pos);

        _vector.x = (x - _pos.x);
        _vector.y = (y - _pos.y);
        _vector.z = (z - _pos.z);
        setOrientation(m, _vector, up, smooth);
    }
}