#include "Mat3.h"

NS_CC_MATH_BEGIN

/**
* Constructor instantiates a new Mat3 object. The initial
* values for the matrix is that of the identity matrix.
* 默认构造单位矩阵
*
*/

Mat3::Mat3() {
    loadIdentity();
}

/**
* constructs a matrix with the given values.
*
* @param m[0]
*            0x0 in the matrix.
* @param m[1]
*            0x1 in the matrix.
* @param m[2]
*            0x2 in the matrix.
* @param m[3]
*            1x0 in the matrix.
* @param m[4]
*            1x1 in the matrix.
* @param m[5]
*            1x2 in the matrix.
* @param m[6]
*            2x0 in the matrix.
* @param m[7]
*            2x1 in the matrix.
* @param m[8]
*            2x2 in the matrix.
*/

Mat3::Mat3(float m[9]) {

    this->m[0] = m[0];
    this->m[1] = m[1];
    this->m[2] = m[2];
    this->m[3] = m[3];
    this->m[4] = m[4];
    this->m[5] = m[5];
    this->m[6] = m[6];
    this->m[8] = m[7];
    this->m[9] = m[8];
}

/**
* get retrieves a value from the matrix at the given position.
* If the position is invalid a JmeException is thrown.
* 获取指定位置的元素值
*
* @param i
*            the row index.行索引（取值范围：0、1、2）
* @param j
*            the colum index.列索引（取值范围：0、1、2）
* @return the value at (i, j).
*/

float Mat3::get(int i, int j) {
    switch (i) {
    case 0:
        switch (j) {
        case 0:
            return m[0];
        case 1:
            return m[1];
        case 2:
            return m[2];
        }
    case 1:
        switch (j) {
        case 0:
            return m[3];
        case 1:
            return m[4];
        case 2:
            return m[5];
        }
    case 2:
        switch (j) {
        case 0:
            return m[6];
        case 1:
            return m[7];
        case 2:
            return m[8];
        }
    }

    return 0.0f;
    // throw new JmeException("Invalid indices into matrix.");
}

/**
* getColumn returns one of three columns specified by the
* parameter. This column is returned as a cocos2d::Vec3 object.
* 获取指定列构造的向量
*
* @param i
*            the column to retrieve. Must be between 0 and 2.
* @param store
*            the vector object to store the result in. if null, a new one
*            is created.
* @return the column specified by the index.
*/

cocos2d::Vec3 Mat3::getColumn(int i) {
    cocos2d::Vec3 store;
    switch (i) {
    case 0:
        store.x = m[0];
        store.y = m[3];
        store.z = m[6];
        break;
    case 1:
        store.x = m[1];
        store.y = m[4];
        store.z = m[7];
        break;
    case 2:
        store.x = m[2];
        store.y = m[5];
        store.z = m[8];
        break;
    default:;
        //logger.warning("Invalid column index.");
        //throw new JmeException("Invalid column index. " + i);
    }
    return store;
}

/**
* getRow returns one of three rows as specified by the
* parameter. This row is returned as a cocos2d::Vec3 object.
* 获取指定行构造的向量
*
* @param i
*            the row to retrieve. Must be between 0 and 2.
* @param store
*            the vector object to store the result in. if null, a new one
*            is created.
* @return the row specified by the index.
*/

cocos2d::Vec3 Mat3::getRow(int i) {
    cocos2d::Vec3 store;
    switch (i) {
    case 0:
        store.x = m[0];
        store.y = m[1];
        store.z = m[2];
        break;
    case 1:
        store.x = m[3];
        store.y = m[4];
        store.z = m[5];
        break;
    case 2:
        store.x = m[6];
        store.y = m[7];
        store.z = m[8];
        break;
    default:;
        // throw new JmeException("Invalid row index. " + i);
    }
    return store;
}

std::string Mat3::toString() {
    return "";
}

/**
*
* setColumn sets a particular column of this matrix to that
* represented by the provided vector.
* 根据给定列向量设置矩阵的列
*
* @param i
*            the column to set.
* @param column
*            the data to set.
*/

void Mat3::setColumn(int i, const cocos2d::Vec3& column) {

    switch (i) {
    case 0:
        m[0] = column.x;
        m[3] = column.y;
        m[6] = column.z;
        break;
    case 1:
        m[1] = column.x;
        m[4] = column.y;
        m[7] = column.z;
        break;
    case 2:
        m[2] = column.x;
        m[5] = column.y;
        m[8] = column.z;
        break;
    default:;
        //logger.warning("Invalid column index.");
        //throw new JmeException("Invalid column index. " + i);
    }
}

/**
*
* setRow sets a particular row of this matrix to that
* represented by the provided vector.
* 根据给定行向量设置矩阵的行
*
* @param i
*            the row to set.
* @param row
*            the data to set.
*/

void Mat3::setRow(int i, const cocos2d::Vec3& row) {
    switch (i) {
    case 0:
        m[0] = row.x;
        m[1] = row.y;
        m[2] = row.z;
        break;
    case 1:
        m[3] = row.x;
        m[4] = row.y;
        m[5] = row.z;
        break;
    case 2:
        m[6] = row.x;
        m[7] = row.y;
        m[8] = row.z;
        break;
    default:;
        // logger.warning("Invalid row index.");
        // throw new JmeException("Invalid row index. " + i);
    }
}

/**
* set places a given value into the matrix at the given
* position. If the position is invalid a JmeException is
* thrown.
* 设定某位置的值
*
* @param i
*            the row index.
* @param j
*            the colum index.
* @param value
*            the value for (i, j).
*/

void Mat3::set(int i, int j, float value) {
    switch (i) {
    case 0:
        switch (j) {
        case 0:
            m[0] = value;
            return;
        case 1:
            m[1] = value;
            return;
        case 2:
            m[2] = value;
            return;
        }
    case 1:
        switch (j) {
        case 0:
            m[3] = value;
            return;
        case 1:
            m[4] = value;
            return;
        case 2:
            m[5] = value;
            return;
        }
    case 2:
        switch (j) {
        case 0:
            m[6] = value;
            return;
        case 1:
            m[7] = value;
            return;
        case 2:
            m[8] = value;
            return;
        }
    }

    //logger.warning("Invalid matrix index.");
    //throw new JmeException("Invalid indices into matrix.");
}

/**
*
* set sets the values of the matrix to those supplied by the
* 3x3 two dimenion array.
* 用二维数组设置矩阵各元素值
*
* @param matrix
*            the new values of the matrix.
* @throws JmeException
*             if the array is not of size 9.
*/

void Mat3::set(float matrix[3][3]) {
    //if (matrix.length != 3 || matrix[0].length != 3) {
    //    throw new JmeException("Array must be of size 9.");
    //}

    m[0] = matrix[0][0];
    m[1] = matrix[0][1];
    m[2] = matrix[0][2];
    m[3] = matrix[1][0];
    m[4] = matrix[1][1];
    m[5] = matrix[1][2];
    m[6] = matrix[2][0];
    m[7] = matrix[2][1];
    m[8] = matrix[2][2];
}

/**
* Recreate Matrix using the provided axis.
* 根据给定各列向量构造矩阵
*
* @param uAxis
*            cocos2d::Vec3
* @param vAxis
*            cocos2d::Vec3
* @param wAxis
*            cocos2d::Vec3
*/

void Mat3::set(const cocos2d::Vec3& uAxis, const cocos2d::Vec3& vAxis, const cocos2d::Vec3& wAxis) {
    m[0] = uAxis.x;
    m[3] = uAxis.y;
    m[6] = uAxis.z;

    m[1] = vAxis.x;
    m[4] = vAxis.y;
    m[7] = vAxis.z;

    m[2] = wAxis.x;
    m[5] = wAxis.y;
    m[8] = wAxis.z;
}

/**
* set sets the values of this matrix from an array of values;
* 根据给定数组按行或列设置矩阵
*
* @param matrix
*            the matrix to set the value to.
* @param rowMajor
*            whether the incoming data is in row or column major order.
*/

void Mat3::set(float matrix[9], bool rowMajor) {
    //if (matrix.length != 9)
    //    throw new JmeException("Array must be of size 9.");

    if (rowMajor) {
        m[0] = matrix[0];
        m[1] = matrix[1];
        m[2] = matrix[2];
        m[3] = matrix[3];
        m[4] = matrix[4];
        m[5] = matrix[5];
        m[6] = matrix[6];
        m[7] = matrix[7];
        m[8] = matrix[8];
    }
    else {
        m[0] = matrix[0];
        m[1] = matrix[3];
        m[2] = matrix[6];
        m[3] = matrix[1];
        m[4] = matrix[4];
        m[5] = matrix[7];
        m[6] = matrix[2];
        m[7] = matrix[5];
        m[8] = matrix[8];
    }
}

/**
* fromAngleNormalAxis sets this matrix4f to the values
* specified by an angle and a normalized axis of rotation.
* 绕轴axis（单位向量）旋转angle（弧度）角的3D旋转矩阵
*
* @param angle
*            the angle to rotate (in radians).
* @param axis
*            the axis of rotation (already normalized).
*/


/**
* Creates a matrix describing a rotation around the z-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/


/**
* Creates a matrix describing a rotation around the y-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/


/**
* Creates a matrix describing a rotation around the x-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/


/**
* Creates a matrix describing a rotation around the z-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/


/**
* Creates a matrix describing a rotation around the y-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/


/**
* Creates a matrix describing a rotation around the x-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/


/**
* 是否单位矩阵
*
* @return true if this matrix is identity
*/


/**
* loadIdentity sets this matrix to the identity matrix. Where
* all values are zero except those along the diagonal which are one.
* 单位矩阵
*
*/

void Mat3::loadIdentity() {
    m[1] = m[2] = m[3] = m[5] = m[6] = m[7] = 0;
    m[0] = m[4] = m[8] = 1;
}

bool Mat3::isIdentity() {
    return (m[0] == 1 && m[1] == 0 && m[2] == 0)
        && (m[3] == 0 && m[4] == 1 && m[5] == 0)
        && (m[6] == 0 && m[7] == 0 && m[8] == 1);
}

void Mat3::rotateX(float angle)
{
    rotateX(std::sin(angle), std::cos(angle));
}

void Mat3::rotateY(float angle)
{
    rotateY(std::sin(angle), std::cos(angle));
}

void Mat3::rotateZ(float angle)
{
    rotateZ(std::sin(angle), std::cos(angle));
}

void Mat3::rotateX(float s, float c)
{
    Mat3 temp;
    temp.createRotationX(s, c);
    mult(temp);
}

void Mat3::rotateY(float s, float c)
{
    Mat3 temp;
    temp.createRotationY(s, c);
    mult(temp);
}

void Mat3::rotateZ(float s, float c)
{
    Mat3 temp;
    temp.createRotationZ(s, c);
    mult(temp);
}

void Mat3::createRotation(const cocos2d::Vec3& axis, float fSin, float fCos) {
    float x = axis.x;
    float y = axis.y;
    float z = axis.z;
    // Make sure the input axis is normalized.
    float n = x * x + y * y + z * z;
    if (n != 1.0f)
    {
        // Not normalized.
        n = sqrt(n);
        // Prevent divide too close to zero.
        if (n > 0.000001f)
        {
            n = 1.0f / n;
            x *= n;
            y *= n;
            z *= n;
        }
    }

    float fOneMinusCos = ((float)1.0) - fCos;
    float fX2 = x * x;
    float fY2 = y * y;
    float fZ2 = z * z;
    float fXYM = x * y * fOneMinusCos;
    float fXZM = x * z * fOneMinusCos;
    float fYZM = y * z * fOneMinusCos;
    float fXSin = x * fSin;
    float fYSin = y * fSin;
    float fZSin = z * fSin;

    m[0] = fX2 * fOneMinusCos + fCos;
    m[1] = fXYM - fZSin;
    m[2] = fXZM + fYSin;
    m[3] = fXYM + fZSin;
    m[4] = fY2 * fOneMinusCos + fCos;
    m[5] = fYZM - fXSin;
    m[6] = fXZM - fYSin;
    m[7] = fYZM + fXSin;
    m[8] = fZ2 * fOneMinusCos + fCos;
}

/**
* Creates a matrix describing a rotation around the x-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/

void Mat3::createRotationX(float s, float c)
{
    m[4] = c;
    m[5] = s;
    m[7] = -s;
    m[8] = c;
}

/**
* Creates a matrix describing a rotation around the y-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/

void Mat3::createRotationY(float s, float c)
{
    m[0] = c;
    m[2] = -s;
    m[6] = s;
    m[8] = c;
}

/**
* Creates a matrix describing a rotation around the z-axis.
*
* @param angle The angle of rotation (in radians).
* @param dst A matrix to store the result in.
*/

void Mat3::createRotationZ(float s, float c)
{
    m[0] = c;
    m[1] = s;
    m[3] = -s;
    m[4] = c;
}

Mat3& Mat3::mult(const Mat3& mat, Mat3& product) const
{
    float temp00, temp01, temp02;
    float temp10, temp11, temp12;
    float temp20, temp21, temp22;

    temp00 = m[0] * mat.m[0] + m[1] * mat.m[3] + m[2] * mat.m[6];
    temp01 = m[0] * mat.m[1] + m[1] * mat.m[4] + m[2] * mat.m[7];
    temp02 = m[0] * mat.m[2] + m[1] * mat.m[5] + m[2] * mat.m[8];
    temp10 = m[3] * mat.m[0] + m[4] * mat.m[3] + m[5] * mat.m[6];
    temp11 = m[3] * mat.m[1] + m[4] * mat.m[4] + m[5] * mat.m[7];
    temp12 = m[3] * mat.m[2] + m[4] * mat.m[5] + m[5] * mat.m[8];
    temp20 = m[6] * mat.m[0] + m[7] * mat.m[3] + m[8] * mat.m[6];
    temp21 = m[6] * mat.m[1] + m[7] * mat.m[4] + m[8] * mat.m[7];
    temp22 = m[6] * mat.m[2] + m[7] * mat.m[5] + m[8] * mat.m[8];

    product.m[0] = temp00;
    product.m[1] = temp01;
    product.m[2] = temp02;
    product.m[3] = temp10;
    product.m[4] = temp11;
    product.m[5] = temp12;
    product.m[6] = temp20;
    product.m[7] = temp21;
    product.m[8] = temp22;

    return product;
}

/**
* Multiplies this 3x3 matrix by the 1x3 Vector vec and stores the result in
* product.
* 矩阵乘以向量，结果存入参数product中
*
* @param vec
*            The cocos2d::Vec3 to multiply.
* @return The given product vector.
*/

cocos2d::Vec3 Mat3::mult(const cocos2d::Vec3& vec) const {

    cocos2d::Vec3 product;

    float x = vec.x;
    float y = vec.y;
    float z = vec.z;

    product.x = m[0] * x + m[1] * y + m[2] * z;
    product.y = m[3] * x + m[4] * y + m[5] * z;
    product.z = m[6] * x + m[7] * y + m[8] * z;

    return product;
}

/**
* multLocal multiplies this matrix internally by a given float
* scale factor.
* 矩阵标量乘
*
* @param scale
*            the value to scale by.
* @return this Mat3
*/

Mat3& Mat3::multLocal(float scale) {
    m[0] *= scale;
    m[1] *= scale;
    m[2] *= scale;
    m[3] *= scale;
    m[4] *= scale;
    m[5] *= scale;
    m[6] *= scale;
    m[7] *= scale;
    m[8] *= scale;
    return *this;
}

/**
* add adds the values of a parameter matrix to this matrix.
* 矩阵加法
*
* @param mat
*            the matrix to add to this.
*/

Mat3& Mat3::addLocal(const Mat3& mat) {
    m[0] += mat.m[0];
    m[1] += mat.m[1];
    m[2] += mat.m[2];
    m[3] += mat.m[3];
    m[4] += mat.m[4];
    m[5] += mat.m[5];
    m[6] += mat.m[6];
    m[7] += mat.m[7];
    m[8] += mat.m[8];
    return *this;
}

/**
* Transposes this matrix in place. Returns this matrix for chaining
* 转置矩阵
*
* @return This matrix after transpose
*/

Mat3& Mat3::transposeLocal() {
    float tmp[9];
    get(tmp, false);
    set(tmp, true);
    return *this;
}

/**
* Inverts this matrix and stores it in the given store.
* 逆矩阵，保存在参数中，不改变自身
*
* @return The store
*/

Mat3 Mat3::invertNew(void) {
    Mat3 store;
    float det = determinant();
    if (std::abs(det) <= 0)
        return store.zero();

    store.m[0] = m[4] * m[8] - m[5] * m[7];
    store.m[1] = m[2] * m[7] - m[1] * m[8];
    store.m[2] = m[1] * m[5] - m[2] * m[4];
    store.m[3] = m[5] * m[6] - m[3] * m[8];
    store.m[4] = m[0] * m[8] - m[2] * m[6];
    store.m[5] = m[2] * m[3] - m[0] * m[5];
    store.m[6] = m[3] * m[7] - m[4] * m[6];
    store.m[7] = m[1] * m[6] - m[0] * m[7];
    store.m[8] = m[0] * m[4] - m[1] * m[3];

    store.multLocal(1 / det);
    return store;
}

/**
* Inverts this matrix locally.
* 逆矩阵，改变自身
*
* @return this
*/

Mat3& Mat3::invertLocal() {
    float det = determinant();
    if (std::abs(det) <= FLT_EPSILON)
        return zero();

    float f00 = m[4] * m[8] - m[5] * m[7];
    float f01 = m[2] * m[7] - m[1] * m[8];
    float f02 = m[1] * m[5] - m[2] * m[4];
    float f10 = m[5] * m[6] - m[3] * m[8];
    float f11 = m[0] * m[8] - m[2] * m[6];
    float f12 = m[2] * m[3] - m[0] * m[5];
    float f20 = m[3] * m[7] - m[4] * m[6];
    float f21 = m[1] * m[6] - m[0] * m[7];
    float f22 = m[0] * m[4] - m[1] * m[3];

    m[0] = f00;
    m[1] = f01;
    m[2] = f02;
    m[3] = f10;
    m[4] = f11;
    m[5] = f12;
    m[6] = f20;
    m[7] = f21;
    m[8] = f22;

    multLocal(1 / det);
    return *this;
}

/**
* Places the adjoint of this matrix in store (creates store if null.)
* 伴随矩阵
*
* @param store
*            The matrix to store the result in. If null, a new matrix is
*            created.
* @return store
*/

Mat3 Mat3::adjoint() {
    Mat3 store;

    store.m[0] = m[4] * m[8] - m[5] * m[7];
    store.m[1] = m[2] * m[7] - m[1] * m[8];
    store.m[2] = m[1] * m[5] - m[2] * m[4];
    store.m[3] = m[5] * m[6] - m[3] * m[8];
    store.m[4] = m[0] * m[8] - m[2] * m[6];
    store.m[5] = m[2] * m[3] - m[0] * m[5];
    store.m[6] = m[3] * m[7] - m[4] * m[6];
    store.m[7] = m[1] * m[6] - m[0] * m[7];
    store.m[8] = m[0] * m[4] - m[1] * m[3];

    return store;
}

/**
* determinant generates the determinate of this matrix.
* 矩阵的行列式
*
* @return the determinate
*/

float Mat3::determinant() {
    float fCo00 = m[4] * m[8] - m[5] * m[7];
    float fCo10 = m[5] * m[6] - m[3] * m[8];
    float fCo20 = m[3] * m[7] - m[4] * m[6];
    float fDet = m[0] * fCo00 + m[1] * fCo10 + m[2] * fCo20;
    return fDet;
}

/**
* Sets all of the values in this matrix to zero.
* 重置矩阵，各元素置为0
*
* @return this matrix
*/

Mat3& Mat3::zero() {
    m[0] = m[1] = m[2] = m[3] = m[4] = m[5] = m[6] = m[7] = m[8] = 0.0f;
    return *this;
}

/**
* transposeNew returns a transposed version of this matrix.
* 转置矩阵
*
* @return The new Mat3 object.
*/

Mat3 Mat3::transposeNew() {
    float temp[9] = { m[0], m[3], m[6], m[1], m[4], m[7], m[2], m[5], m[8] };
    return Mat3(temp);
}

/**
* are these two matrices the same? they are is they both have the same mXX
* values.
*
* @param o
*            the object to compare for equality
* @return true if they are equal
*/

bool Mat3::equals(const Mat3& o) const {
    return memcmp(&o, this, sizeof(o)) == 0;
}

/**
* A function for creating a rotation matrix that rotates a vector called
* "start" into another vector called "end".
* 创建一个旋转矩阵，从向量start旋转到end
*
* @param start
*            normalized non-zero starting vector
* @param end
*            normalized non-zero ending vector
* @see "Tomas M?ller, John Hughes /"Efficiently Building a Matrix to Rotate
*      / One Vector to Another/" Journal of Graphics Tools, 4(4):1-4, 1999"
*/

void Mat3::fromStartEndVectors(cocos2d::Vec3 start, cocos2d::Vec3 end) {
    cocos2d::Vec3 v;
    float e, h, f;

    cocos2d::Vec3::cross(start, end, &v);
    e = start.dot(end);
    f = (e < 0) ? -e : e;

    // if "from" and "to" vectors are nearly parallel
    if (f > 1.0f - FLT_EPSILON) {
        cocos2d::Vec3 u;
        cocos2d::Vec3 x;
        float c1, c2, c3; /* coefficients for later use */
        int i, j;

        x.x = (start.x > 0.0) ? start.x : -start.x;
        x.y = (start.y > 0.0) ? start.y : -start.y;
        x.z = (start.z > 0.0) ? start.z : -start.z;

        if (x.x < x.y) {
            if (x.x < x.z) {
                x.x = 1.0f;
                x.y = x.z = 0.0f;
            }
            else {
                x.z = 1.0f;
                x.x = x.y = 0.0f;
            }
        }
        else {
            if (x.y < x.z) {
                x.y = 1.0f;
                x.x = x.z = 0.0f;
            }
            else {
                x.z = 1.0f;
                x.x = x.y = 0.0f;
            }
        }

        u.x = x.x - start.x;
        u.y = x.y - start.y;
        u.z = x.z - start.z;
        v.x = x.x - end.x;
        v.y = x.y - end.y;
        v.z = x.z - end.z;

        c1 = 2.0f / u.dot(u);
        c2 = 2.0f / v.dot(v);
        c3 = c1 * c2 * u.dot(v);

        for (i = 0; i < 3; i++) {
            for (j = 0; j < 3; j++) {
                float val = -c1 * (&u.x)[i] * (&u.x)[j] - c2 * (&v.x)[i]
                    * (&v.x)[j] + c3 * (&v.x)[i] * (&u.x)[j];
                set(i, j, val);
            }
            float val = get(i, i);
            set(i, i, val + 1.0f);
        }
    }
    else {
        // the most common case, unless "start"="end", or "start"=-"end"
        float hvx, hvz, hvxy, hvxz, hvyz;
        h = 1.0f / (1.0f + e);
        hvx = h * v.x;
        hvz = h * v.z;
        hvxy = hvx * v.y;
        hvxz = hvx * v.z;
        hvyz = hvz * v.y;
        set(0, 0, e + hvx * v.x);
        set(0, 1, hvxy - v.z);
        set(0, 2, hvxz + v.y);

        set(1, 0, hvxy + v.z);
        set(1, 1, e + h * v.y * v.y);
        set(1, 2, hvyz - v.x);

        set(2, 0, hvxz - v.y);
        set(2, 1, hvyz + v.x);
        set(2, 2, e + hvz * v.z);
    }
}

/**
* scale scales the operation performed by this matrix on a
* per-component basis.
* 标量乘行向量，各列分别相乘
*
* @param scale
*            The scale applied to each of the X, Y and Z output values.
*/

void Mat3::scale(const cocos2d::Vec3& scale) {
    m[0] *= scale.x;
    m[3] *= scale.x;
    m[6] *= scale.x;
    m[1] *= scale.y;
    m[4] *= scale.y;
    m[7] *= scale.y;
    m[2] *= scale.z;
    m[5] *= scale.z;
    m[8] *= scale.z;
}

bool Mat3::equalIdentity(const Mat3& mat) {
    if (std::abs(mat.m[0] - 1) > 1e-4)
        return false;
    if (std::abs(mat.m[4] - 1) > 1e-4)
        return false;
    if (std::abs(mat.m[8] - 1) > 1e-4)
        return false;

    if (std::abs(mat.m[1]) > 1e-4)
        return false;
    if (std::abs(mat.m[2]) > 1e-4)
        return false;

    if (std::abs(mat.m[3]) > 1e-4)
        return false;
    if (std::abs(mat.m[5]) > 1e-4)
        return false;

    if (std::abs(mat.m[6]) > 1e-4)
        return false;
    if (std::abs(mat.m[7]) > 1e-4)
        return false;

    return true;
}


NS_CC_MATH_END