are matrices row-major or column-major?

[boltik99]

is this documentation correct?

// ---------------------------------------------------------------------------
/** @brief Represents a row-major 4x4 matrix, use this for homogeneous
 *   coordinates.
 *
 *  There's much confusion about matrix layouts (column vs. row order).
 *  This is *always* a row-major matrix. Not even with the
 *  #aiProcess_ConvertToLeftHanded flag, which absolutely does not affect
 *  matrix order - it just affects the handedness of the coordinate system
 *  defined thereby.
 */
template<typename TReal>
class aiMatrix4x4t {
...

as long as i understand correctly row-major means that position vector is at m[3][0], m[3][1], m[3][2], but at definition of DecomposeNoScaling i saw

// ----------------------------------------------------------------------------------------
template <typename TReal>
AI_FORCE_INLINE void aiMatrix4x4t<TReal>::DecomposeNoScaling(aiQuaterniont<TReal> &rotation,
        aiVector3t<TReal> &position) const {
    const aiMatrix4x4t<TReal> &_this = *this;

    // extract translation
    position.x = _this[0][3];
    position.y = _this[1][3];
    position.z = _this[2][3];

i need to know if im wrong to find transform bug

[kimkulling]

Hi,

as usual, there are many problems with how to use our matrices. So when you read a little bit in our in-code documentation based on Doxygen you can find the information you are looking for:

/** @brief Represents a row-major 3x3 matrix
 *
 *  There's much confusion about matrix layouts (column vs. row order).
 *  This is *always* a row-major matrix. Not even with the
 *  #aiProcess_ConvertToLeftHanded flag, which absolutely does not affect
 *  matrix order - it just affects the handedness of the coordinate system
 *  defined thereby.

[KeyC0de]

Assimp's matrices may be row-major memory wise, meaning that elements in the same row lie in consecutive memory addresses.
But they are column-major mathematics & api-wise, ie their translation components lie in the 4th column (like in OpenGL).

There's 2 types of 'matrix majority'!