text: /*
   * Copyright (c), Recep Aslantas.
   *
   * MIT License (MIT), http://opensource.org/licenses/MIT
   * Full license can be found in the LICENSE file
   */
  
  /*!
   * Most of functions in this header are optimized manually with SIMD
   * if available. You dont need to call/incude SIMD headers manually
   */
  
  /*
   Macros:
     GLM_MAT4_IDENTITY_INIT
     GLM_MAT4_ZERO_INIT
     GLM_MAT4_IDENTITY
     GLM_MAT4_ZERO
  
   Functions:
     CGLM_INLINE void  glm_mat4_ucopy(mat4 mat, mat4 dest);
     CGLM_INLINE void  glm_mat4_copy(mat4 mat, mat4 dest);
     CGLM_INLINE void  glm_mat4_identity(mat4 mat);
     CGLM_INLINE void  glm_mat4_identity_array(mat4 * restrict mat, size_t count);
     CGLM_INLINE void  glm_mat4_zero(mat4 mat);
     CGLM_INLINE void  glm_mat4_pick3(mat4 mat, mat3 dest);
     CGLM_INLINE void  glm_mat4_pick3t(mat4 mat, mat3 dest);
     CGLM_INLINE void  glm_mat4_ins3(mat3 mat, mat4 dest);
     CGLM_INLINE void  glm_mat4_mul(mat4 m1, mat4 m2, mat4 dest);
     CGLM_INLINE void  glm_mat4_mulN(mat4 *matrices[], int len, mat4 dest);
     CGLM_INLINE void  glm_mat4_mulv(mat4 m, vec4 v, vec4 dest);
     CGLM_INLINE void  glm_mat4_mulv3(mat4 m, vec3 v, vec3 dest);
     CGLM_INLINE float glm_mat4_trace(mat4 m);
     CGLM_INLINE float glm_mat4_trace3(mat4 m);
     CGLM_INLINE void  glm_mat4_quat(mat4 m, versor dest) ;
     CGLM_INLINE void  glm_mat4_transpose_to(mat4 m, mat4 dest);
     CGLM_INLINE void  glm_mat4_transpose(mat4 m);
     CGLM_INLINE void  glm_mat4_scale_p(mat4 m, float s);
     CGLM_INLINE void  glm_mat4_scale(mat4 m, float s);
     CGLM_INLINE float glm_mat4_det(mat4 mat);
     CGLM_INLINE void  glm_mat4_inv(mat4 mat, mat4 dest);
     CGLM_INLINE void  glm_mat4_inv_fast(mat4 mat, mat4 dest);
     CGLM_INLINE void  glm_mat4_swap_col(mat4 mat, int col1, int col2);
     CGLM_INLINE void  glm_mat4_swap_row(mat4 mat, int row1, int row2);
     CGLM_INLINE float glm_mat4_rmc(vec4 r, mat4 m, vec4 c);
   */
  
  #ifndef cglm_mat_h
  #define cglm_mat_h
  
  #include "common.h"
  #include "vec4.h"
  #include "vec3.h"
  
  #ifdef CGLM_SSE_FP
  #  include "simd/sse2/mat4.h"
  #endif
  
  #ifdef CGLM_AVX_FP
  #  include "simd/avx/mat4.h"
  #endif
  
  #ifdef CGLM_NEON_FP
  #  include "simd/neon/mat4.h"
  #endif
  
  #ifdef DEBUG
  # include <assert.h>
  #endif
  
  #define GLM_MAT4_IDENTITY_INIT  {{1.0f, 0.0f, 0.0f, 0.0f},                    \
                                   {0.0f, 1.0f, 0.0f, 0.0f},                    \
                                   {0.0f, 0.0f, 1.0f, 0.0f},                    \
                                   {0.0f, 0.0f, 0.0f, 1.0f}}
  
  #define GLM_MAT4_ZERO_INIT      {{0.0f, 0.0f, 0.0f, 0.0f},                    \
                                   {0.0f, 0.0f, 0.0f, 0.0f},                    \
                                   {0.0f, 0.0f, 0.0f, 0.0f},                    \
                                   {0.0f, 0.0f, 0.0f, 0.0f}}
  
  /* for C only */
  #define GLM_MAT4_IDENTITY ((mat4)GLM_MAT4_IDENTITY_INIT)
  #define GLM_MAT4_ZERO     ((mat4)GLM_MAT4_ZERO_INIT)
  
  /* DEPRECATED! use _copy, _ucopy versions */
  #define glm_mat4_udup(mat, dest) glm_mat4_ucopy(mat, dest)
  #define glm_mat4_dup(mat, dest)  glm_mat4_copy(mat, dest)
  
  /* DEPRECATED! default is precise now. */
  #define glm_mat4_inv_precise(mat, dest) glm_mat4_inv(mat, dest)
  
  /*!
   * @brief copy all members of [mat] to [dest]
   *
   * matrix may not be aligned, u stands for unaligned, this may be useful when
   * copying a matrix from external source e.g. asset importer...
   *
   * @param[in]  mat  source
   * @param[out] dest destination
   */
  CGLM_INLINE
  void
  glm_mat4_ucopy(mat4 mat, mat4 dest) {
    dest[0][0] = mat[0][0];  dest[1][0] = mat[1][0];
    dest[0][1] = mat[0][1];  dest[1][1] = mat[1][1];
    dest[0][2] = mat[0][2];  dest[1][2] = mat[1][2];
    dest[0][3] = mat[0][3];  dest[1][3] = mat[1][3];
  
    dest[2][0] = mat[2][0];  dest[3][0] = mat[3][0];
    dest[2][1] = mat[2][1];  dest[3][1] = mat[3][1];
    dest[2][2] = mat[2][2];  dest[3][2] = mat[3][2];
    dest[2][3] = mat[2][3];  dest[3][3] = mat[3][3];
  }
  
  /*!
   * @brief copy all members of [mat] to [dest]
   *
   * @param[in]  mat  source
   * @param[out] dest destination
   */
  CGLM_INLINE
  void
  glm_mat4_copy(mat4 mat, mat4 dest) {
  #ifdef __AVX__
    glmm_store256(dest[0], glmm_load256(mat[0]));
    glmm_store256(dest[2], glmm_load256(mat[2]));
  #elif defined( __SSE__ ) || defined( __SSE2__ )
    glmm_store(dest[0], glmm_load(mat[0]));
    glmm_store(dest[1], glmm_load(mat[1]));
    glmm_store(dest[2], glmm_load(mat[2]));
    glmm_store(dest[3], glmm_load(mat[3]));
  #elif defined(CGLM_NEON_FP)
    vst1q_f32(dest[0], vld1q_f32(mat[0]));
    vst1q_f32(dest[1], vld1q_f32(mat[1]));
    vst1q_f32(dest[2], vld1q_f32(mat[2]));
    vst1q_f32(dest[3], vld1q_f32(mat[3]));
  #else
    glm_mat4_ucopy(mat, dest);
  #endif
  }
  
  /*!
   * @brief make given matrix identity. It is identical with below, 
   *        but it is more easy to do that with this func especially for members
   *        e.g. glm_mat4_identity(aStruct->aMatrix);
   *
   * @code
   * glm_mat4_copy(GLM_MAT4_IDENTITY, mat); // C only
   *
   * // or
   * mat4 mat = GLM_MAT4_IDENTITY_INIT;
   * @endcode
   *
   * @param[in, out]  mat  destination
   */
  CGLM_INLINE
  void
  glm_mat4_identity(mat4 mat) {
    CGLM_ALIGN_MAT mat4 t = GLM_MAT4_IDENTITY_INIT;
    glm_mat4_copy(t, mat);
  }
  
  /*!
   * @brief make given matrix array's each element identity matrix
   *
   * @param[in, out]  mat   matrix array (must be aligned (16/32)
   *                        if alignment is not disabled)
   *
   * @param[in]       count count of matrices
   */
  CGLM_INLINE
  void
  glm_mat4_identity_array(mat4 * __restrict mat, size_t count) {
    CGLM_ALIGN_MAT mat4 t = GLM_MAT4_IDENTITY_INIT;
    size_t i;
  
    for (i = 0; i < count; i++) {
      glm_mat4_copy(t, mat[i]);
    }
  }
  
  /*!
   * @brief make given matrix zero.
   *
   * @param[in, out]  mat  matrix
   */
  CGLM_INLINE
  void
  glm_mat4_zero(mat4 mat) {
    CGLM_ALIGN_MAT mat4 t = GLM_MAT4_ZERO_INIT;
    glm_mat4_copy(t, mat);
  }
  
  /*!
   * @brief copy upper-left of mat4 to mat3
   *
   * @param[in]  mat  source
   * @param[out] dest destination
   */
  CGLM_INLINE
  void
  glm_mat4_pick3(mat4 mat, mat3 dest) {
    dest[0][0] = mat[0][0];
    dest[0][1] = mat[0][1];
    dest[0][2] = mat[0][2];
  
    dest[1][0] = mat[1][0];
    dest[1][1] = mat[1][1];
    dest[1][2] = mat[1][2];
  
    dest[2][0] = mat[2][0];
    dest[2][1] = mat[2][1];
    dest[2][2] = mat[2][2];
  }
  
  /*!
   * @brief copy upper-left of mat4 to mat3 (transposed)
   *
   * the postfix t stands for transpose
   *
   * @param[in]  mat  source
   * @param[out] dest destination
   */
  CGLM_INLINE
  void
  glm_mat4_pick3t(mat4 mat, mat3 dest) {
    dest[0][0] = mat[0][0];
    dest[0][1] = mat[1][0];
    dest[0][2] = mat[2][0];
  
    dest[1][0] = mat[0][1];
    dest[1][1] = mat[1][1];
    dest[1][2] = mat[2][1];
  
    dest[2][0] = mat[0][2];
    dest[2][1] = mat[1][2];
    dest[2][2] = mat[2][2];
  }
  
  /*!
   * @brief copy mat3 to mat4's upper-left
   *
   * @param[in]  mat  source
   * @param[out] dest destination
   */
  CGLM_INLINE
  void
  glm_mat4_ins3(mat3 mat, mat4 dest) {
    dest[0][0] = mat[0][0];
    dest[0][1] = mat[0][1];
    dest[0][2] = mat[0][2];
  
    dest[1][0] = mat[1][0];
    dest[1][1] = mat[1][1];
    dest[1][2] = mat[1][2];
  
    dest[2][0] = mat[2][0];
    dest[2][1] = mat[2][1];
    dest[2][2] = mat[2][2];
  }
  
  /*!
   * @brief multiply m1 and m2 to dest
   *
   * m1, m2 and dest matrices can be same matrix, it is possible to write this:
   *
   * @code
   * mat4 m = GLM_MAT4_IDENTITY_INIT;
   * glm_mat4_mul(m, m, m);
   * @endcode
   *
   * @param[in]  m1   left matrix
   * @param[in]  m2   right matrix
   * @param[out] dest destination matrix
   */
  CGLM_INLINE
  void
  glm_mat4_mul(mat4 m1, mat4 m2, mat4 dest) {
  #ifdef __AVX__
    glm_mat4_mul_avx(m1, m2, dest);
  #elif defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_mul_sse2(m1, m2, dest);
  #elif defined(CGLM_NEON_FP)
    glm_mat4_mul_neon(m1, m2, dest);
  #else
    float a00 = m1[0][0], a01 = m1[0][1], a02 = m1[0][2], a03 = m1[0][3],
          a10 = m1[1][0], a11 = m1[1][1], a12 = m1[1][2], a13 = m1[1][3],
          a20 = m1[2][0], a21 = m1[2][1], a22 = m1[2][2], a23 = m1[2][3],
          a30 = m1[3][0], a31 = m1[3][1], a32 = m1[3][2], a33 = m1[3][3],
  
          b00 = m2[0][0], b01 = m2[0][1], b02 = m2[0][2], b03 = m2[0][3],
          b10 = m2[1][0], b11 = m2[1][1], b12 = m2[1][2], b13 = m2[1][3],
          b20 = m2[2][0], b21 = m2[2][1], b22 = m2[2][2], b23 = m2[2][3],
          b30 = m2[3][0], b31 = m2[3][1], b32 = m2[3][2], b33 = m2[3][3];
  
    dest[0][0] = a00 * b00 + a10 * b01 + a20 * b02 + a30 * b03;
    dest[0][1] = a01 * b00 + a11 * b01 + a21 * b02 + a31 * b03;
    dest[0][2] = a02 * b00 + a12 * b01 + a22 * b02 + a32 * b03;
    dest[0][3] = a03 * b00 + a13 * b01 + a23 * b02 + a33 * b03;
    dest[1][0] = a00 * b10 + a10 * b11 + a20 * b12 + a30 * b13;
    dest[1][1] = a01 * b10 + a11 * b11 + a21 * b12 + a31 * b13;
    dest[1][2] = a02 * b10 + a12 * b11 + a22 * b12 + a32 * b13;
    dest[1][3] = a03 * b10 + a13 * b11 + a23 * b12 + a33 * b13;
    dest[2][0] = a00 * b20 + a10 * b21 + a20 * b22 + a30 * b23;
    dest[2][1] = a01 * b20 + a11 * b21 + a21 * b22 + a31 * b23;
    dest[2][2] = a02 * b20 + a12 * b21 + a22 * b22 + a32 * b23;
    dest[2][3] = a03 * b20 + a13 * b21 + a23 * b22 + a33 * b23;
    dest[3][0] = a00 * b30 + a10 * b31 + a20 * b32 + a30 * b33;
    dest[3][1] = a01 * b30 + a11 * b31 + a21 * b32 + a31 * b33;
    dest[3][2] = a02 * b30 + a12 * b31 + a22 * b32 + a32 * b33;
    dest[3][3] = a03 * b30 + a13 * b31 + a23 * b32 + a33 * b33;
  #endif
  }
  
  /*!
   * @brief mupliply N mat4 matrices and store result in dest
   *
   * this function lets you multiply multiple (more than two or more...) matrices
   * <br><br>multiplication will be done in loop, this may reduce instructions
   * size but if <b>len</b> is too small then compiler may unroll whole loop,
   * usage:
   * @code
   * mat m1, m2, m3, m4, res;
   *
   * glm_mat4_mulN((mat4 *[]){&m1, &m2, &m3, &m4}, 4, res);
   * @endcode
   *
   * @warning matrices parameter is pointer array not mat4 array!
   *
   * @param[in]  matrices mat4 * array
   * @param[in]  len      matrices count
   * @param[out] dest     result
   */
  CGLM_INLINE
  void
  glm_mat4_mulN(mat4 * __restrict matrices[], uint32_t len, mat4 dest) {
    uint32_t i;
  
  #ifdef DEBUG
    assert(len > 1 && "there must be least 2 matrices to go!");
  #endif
  
    glm_mat4_mul(*matrices[0], *matrices[1], dest);
  
    for (i = 2; i < len; i++)
      glm_mat4_mul(dest, *matrices[i], dest);
  }
  
  /*!
   * @brief multiply mat4 with vec4 (column vector) and store in dest vector
   *
   * @param[in]  m    mat4 (left)
   * @param[in]  v    vec4 (right, column vector)
   * @param[out] dest vec4 (result, column vector)
   */
  CGLM_INLINE
  void
  glm_mat4_mulv(mat4 m, vec4 v, vec4 dest) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_mulv_sse2(m, v, dest);
  #elif defined(CGLM_NEON_FP)
    glm_mat4_mulv_neon(m, v, dest);
  #else
    vec4 res;
    res[0] = m[0][0] * v[0] + m[1][0] * v[1] + m[2][0] * v[2] + m[3][0] * v[3];
    res[1] = m[0][1] * v[0] + m[1][1] * v[1] + m[2][1] * v[2] + m[3][1] * v[3];
    res[2] = m[0][2] * v[0] + m[1][2] * v[1] + m[2][2] * v[2] + m[3][2] * v[3];
    res[3] = m[0][3] * v[0] + m[1][3] * v[1] + m[2][3] * v[2] + m[3][3] * v[3];
    glm_vec4_copy(res, dest);
  #endif
  }
  
  /*!
   * @brief trace of matrix
   *
   * sum of the elements on the main diagonal from upper left to the lower right
   *
   * @param[in]  m matrix
   */
  CGLM_INLINE
  float
  glm_mat4_trace(mat4 m) {
    return m[0][0] + m[1][1] + m[2][2] + m[3][3];
  }
  
  /*!
   * @brief trace of matrix (rotation part)
   *
   * sum of the elements on the main diagonal from upper left to the lower right
   *
   * @param[in]  m matrix
   */
  CGLM_INLINE
  float
  glm_mat4_trace3(mat4 m) {
    return m[0][0] + m[1][1] + m[2][2];
  }
  
  /*!
   * @brief convert mat4's rotation part to quaternion
   *
   * @param[in]  m    affine matrix
   * @param[out] dest destination quaternion
   */
  CGLM_INLINE
  void
  glm_mat4_quat(mat4 m, versor dest) {
    float trace, r, rinv;
  
    /* it seems using like m12 instead of m[1][2] causes extra instructions */
  
    trace = m[0][0] + m[1][1] + m[2][2];
    if (trace >= 0.0f) {
      r       = sqrtf(1.0f + trace);
      rinv    = 0.5f / r;
  
      dest[0] = rinv * (m[1][2] - m[2][1]);
      dest[1] = rinv * (m[2][0] - m[0][2]);
      dest[2] = rinv * (m[0][1] - m[1][0]);
      dest[3] = r    * 0.5f;
    } else if (m[0][0] >= m[1][1] && m[0][0] >= m[2][2]) {
      r       = sqrtf(1.0f - m[1][1] - m[2][2] + m[0][0]);
      rinv    = 0.5f / r;
  
      dest[0] = r    * 0.5f;
      dest[1] = rinv * (m[0][1] + m[1][0]);
      dest[2] = rinv * (m[0][2] + m[2][0]);
      dest[3] = rinv * (m[1][2] - m[2][1]);
    } else if (m[1][1] >= m[2][2]) {
      r       = sqrtf(1.0f - m[0][0] - m[2][2] + m[1][1]);
      rinv    = 0.5f / r;
  
      dest[0] = rinv * (m[0][1] + m[1][0]);
      dest[1] = r    * 0.5f;
      dest[2] = rinv * (m[1][2] + m[2][1]);
      dest[3] = rinv * (m[2][0] - m[0][2]);
    } else {
      r       = sqrtf(1.0f - m[0][0] - m[1][1] + m[2][2]);
      rinv    = 0.5f / r;
  
      dest[0] = rinv * (m[0][2] + m[2][0]);
      dest[1] = rinv * (m[1][2] + m[2][1]);
      dest[2] = r    * 0.5f;
      dest[3] = rinv * (m[0][1] - m[1][0]);
    }
  }
  
  /*!
   * @brief multiply vector with mat4
   *
   * actually the result is vec4, after multiplication the last component
   * is trimmed. if you need it don't use this func.
   *
   * @param[in]  m    mat4(affine transform)
   * @param[in]  v    vec3
   * @param[in]  last 4th item to make it vec4
   * @param[out] dest result vector (vec3)
   */
  CGLM_INLINE
  void
  glm_mat4_mulv3(mat4 m, vec3 v, float last, vec3 dest) {
    vec4 res;
    glm_vec4(v, last, res);
    glm_mat4_mulv(m, res, res);
    glm_vec3(res, dest);
  }
  
  /*!
   * @brief transpose mat4 and store in dest
   *
   * source matrix will not be transposed unless dest is m
   *
   * @param[in]  m    matrix
   * @param[out] dest result
   */
  CGLM_INLINE
  void
  glm_mat4_transpose_to(mat4 m, mat4 dest) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_transp_sse2(m, dest);
  #elif defined(CGLM_NEON_FP)
    glm_mat4_transp_neon(m, dest);
  #else
    dest[0][0] = m[0][0]; dest[1][0] = m[0][1];
    dest[0][1] = m[1][0]; dest[1][1] = m[1][1];
    dest[0][2] = m[2][0]; dest[1][2] = m[2][1];
    dest[0][3] = m[3][0]; dest[1][3] = m[3][1];
    dest[2][0] = m[0][2]; dest[3][0] = m[0][3];
    dest[2][1] = m[1][2]; dest[3][1] = m[1][3];
    dest[2][2] = m[2][2]; dest[3][2] = m[2][3];
    dest[2][3] = m[3][2]; dest[3][3] = m[3][3];
  #endif
  }
  
  /*!
   * @brief tranpose mat4 and store result in same matrix
   *
   * @param[in, out] m source and dest
   */
  CGLM_INLINE
  void
  glm_mat4_transpose(mat4 m) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_transp_sse2(m, m);
  #elif defined(CGLM_NEON_FP)
    glm_mat4_transp_neon(m, m);
  #else
    mat4 d;
    glm_mat4_transpose_to(m, d);
    glm_mat4_ucopy(d, m);
  #endif
  }
  
  /*!
   * @brief scale (multiply with scalar) matrix without simd optimization
   *
   * multiply matrix with scalar
   *
   * @param[in, out] m matrix
   * @param[in]      s scalar
   */
  CGLM_INLINE
  void
  glm_mat4_scale_p(mat4 m, float s) {
    m[0][0] *= s; m[0][1] *= s; m[0][2] *= s; m[0][3] *= s;
    m[1][0] *= s; m[1][1] *= s; m[1][2] *= s; m[1][3] *= s;
    m[2][0] *= s; m[2][1] *= s; m[2][2] *= s; m[2][3] *= s;
    m[3][0] *= s; m[3][1] *= s; m[3][2] *= s; m[3][3] *= s;
  }
  
  /*!
   * @brief scale (multiply with scalar) matrix
   *
   * multiply matrix with scalar
   *
   * @param[in, out] m matrix
   * @param[in]      s scalar
   */
  CGLM_INLINE
  void
  glm_mat4_scale(mat4 m, float s) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_scale_sse2(m, s);
  #elif defined(CGLM_NEON_FP)
    glm_mat4_scale_neon(m, s);
  #else
    glm_mat4_scale_p(m, s);
  #endif
  }
  
  /*!
   * @brief mat4 determinant
   *
   * @param[in] mat matrix
   *
   * @return determinant
   */
  CGLM_INLINE
  float
  glm_mat4_det(mat4 mat) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    return glm_mat4_det_sse2(mat);
  #else
    /* [square] det(A) = det(At) */
    float t[6];
    float a = mat[0][0], b = mat[0][1], c = mat[0][2], d = mat[0][3],
          e = mat[1][0], f = mat[1][1], g = mat[1][2], h = mat[1][3],
          i = mat[2][0], j = mat[2][1], k = mat[2][2], l = mat[2][3],
          m = mat[3][0], n = mat[3][1], o = mat[3][2], p = mat[3][3];
  
    t[0] = k * p - o * l;
    t[1] = j * p - n * l;
    t[2] = j * o - n * k;
    t[3] = i * p - m * l;
    t[4] = i * o - m * k;
    t[5] = i * n - m * j;
  
    return a * (f * t[0] - g * t[1] + h * t[2])
         - b * (e * t[0] - g * t[3] + h * t[4])
         + c * (e * t[1] - f * t[3] + h * t[5])
         - d * (e * t[2] - f * t[4] + g * t[5]);
  #endif
  }
  
  /*!
   * @brief inverse mat4 and store in dest
   *
   * @param[in]  mat  matrix
   * @param[out] dest inverse matrix
   */
  CGLM_INLINE
  void
  glm_mat4_inv(mat4 mat, mat4 dest) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_inv_sse2(mat, dest);
  #else
    float t[6];
    float det;
    float a = mat[0][0], b = mat[0][1], c = mat[0][2], d = mat[0][3],
          e = mat[1][0], f = mat[1][1], g = mat[1][2], h = mat[1][3],
          i = mat[2][0], j = mat[2][1], k = mat[2][2], l = mat[2][3],
          m = mat[3][0], n = mat[3][1], o = mat[3][2], p = mat[3][3];
  
    t[0] = k * p - o * l; t[1] = j * p - n * l; t[2] = j * o - n * k;
    t[3] = i * p - m * l; t[4] = i * o - m * k; t[5] = i * n - m * j;
  
    dest[0][0] =  f * t[0] - g * t[1] + h * t[2];
    dest[1][0] =-(e * t[0] - g * t[3] + h * t[4]);
    dest[2][0] =  e * t[1] - f * t[3] + h * t[5];
    dest[3][0] =-(e * t[2] - f * t[4] + g * t[5]);
  
    dest[0][1] =-(b * t[0] - c * t[1] + d * t[2]);
    dest[1][1] =  a * t[0] - c * t[3] + d * t[4];
    dest[2][1] =-(a * t[1] - b * t[3] + d * t[5]);
    dest[3][1] =  a * t[2] - b * t[4] + c * t[5];
  
    t[0] = g * p - o * h; t[1] = f * p - n * h; t[2] = f * o - n * g;
    t[3] = e * p - m * h; t[4] = e * o - m * g; t[5] = e * n - m * f;
  
    dest[0][2] =  b * t[0] - c * t[1] + d * t[2];
    dest[1][2] =-(a * t[0] - c * t[3] + d * t[4]);
    dest[2][2] =  a * t[1] - b * t[3] + d * t[5];
    dest[3][2] =-(a * t[2] - b * t[4] + c * t[5]);
  
    t[0] = g * l - k * h; t[1] = f * l - j * h; t[2] = f * k - j * g;
    t[3] = e * l - i * h; t[4] = e * k - i * g; t[5] = e * j - i * f;
  
    dest[0][3] =-(b * t[0] - c * t[1] + d * t[2]);
    dest[1][3] =  a * t[0] - c * t[3] + d * t[4];
    dest[2][3] =-(a * t[1] - b * t[3] + d * t[5]);
    dest[3][3] =  a * t[2] - b * t[4] + c * t[5];
  
    det = 1.0f / (a * dest[0][0] + b * dest[1][0]
                + c * dest[2][0] + d * dest[3][0]);
  
    glm_mat4_scale_p(dest, det);
  #endif
  }
  
  /*!
   * @brief inverse mat4 and store in dest
   *
   * this func uses reciprocal approximation without extra corrections
   * e.g Newton-Raphson. this should work faster than normal,
   * to get more precise use glm_mat4_inv version.
   *
   * NOTE: You will lose precision, glm_mat4_inv is more accurate
   *
   * @param[in]  mat  matrix
   * @param[out] dest inverse matrix
   */
  CGLM_INLINE
  void
  glm_mat4_inv_fast(mat4 mat, mat4 dest) {
  #if defined( __SSE__ ) || defined( __SSE2__ )
    glm_mat4_inv_fast_sse2(mat, dest);
  #else
    glm_mat4_inv(mat, dest);
  #endif
  }
  
  /*!
   * @brief swap two matrix columns
   *
   * @param[in,out] mat  matrix
   * @param[in]     col1 col1
   * @param[in]     col2 col2
   */
  CGLM_INLINE
  void
  glm_mat4_swap_col(mat4 mat, int col1, int col2) {
    CGLM_ALIGN(16) vec4 tmp;
    glm_vec4_copy(mat[col1], tmp);
    glm_vec4_copy(mat[col2], mat[col1]);
    glm_vec4_copy(tmp, mat[col2]);
  }
  
  /*!
   * @brief swap two matrix rows
   *
   * @param[in,out] mat  matrix
   * @param[in]     row1 row1
   * @param[in]     row2 row2
   */
  CGLM_INLINE
  void
  glm_mat4_swap_row(mat4 mat, int row1, int row2) {
    CGLM_ALIGN(16) vec4 tmp;
    tmp[0] = mat[0][row1];
    tmp[1] = mat[1][row1];
    tmp[2] = mat[2][row1];
    tmp[3] = mat[3][row1];
  
    mat[0][row1] = mat[0][row2];
    mat[1][row1] = mat[1][row2];
    mat[2][row1] = mat[2][row2];
    mat[3][row1] = mat[3][row2];
  
    mat[0][row2] = tmp[0];
    mat[1][row2] = tmp[1];
    mat[2][row2] = tmp[2];
    mat[3][row2] = tmp[3];
  }
  
  /*!
   * @brief helper for  R (row vector) * M (matrix) * C (column vector)
   *
   * rmc stands for Row * Matrix * Column
   *
   * the result is scalar because R * M = Matrix1x4 (row vector),
   * then Matrix1x4 * Vec4 (column vector) = Matrix1x1 (Scalar)
   *
   * @param[in]  r   row vector or matrix1x4
   * @param[in]  m   matrix4x4
   * @param[in]  c   column vector or matrix4x1
   *
   * @return scalar value e.g. B(s)
   */
  CGLM_INLINE
  float
  glm_mat4_rmc(vec4 r, mat4 m, vec4 c) {
    vec4 tmp;
    glm_mat4_mulv(m, c, tmp);
    return glm_vec4_dot(r, tmp);
  }
  
  #endif /* cglm_mat_h */
  