2018-soft-3d-renderer/include/matrix.h

#ifndef MATRIX_H


#include "point.h"


// STRUCTURE
struct Matrix
{
    inline Matrix(void)
    {
        e11 = 1.0; e12 = 0.0; e13 = 0.0; e14 = 0.0;
        e21 = 0.0; e22 = 1.0; e23 = 0.0; e24 = 0.0;
        e31 = 0.0; e32 = 0.0; e33 = 1.0; e34 = 0.0;
        e41 = 0.0; e42 = 0.0; e43 = 0.0; e44 = 1.0;
    }

    union
    {
        float e[4][4];

        struct
        {
            float e11, e12, e13, e14;
            float e21, e22, e23, e24;
            float e31, e32, e33, e34;
            float e41, e42, e43, e44;
        };
    };
};


// OPERATORS
// m1 * m2
inline Matrix operator*(Matrix m1, Matrix m2)
{
    Matrix result;

    for (int row = 0; row < 4; ++row)
    {
        for (int col = 0; col < 4; ++col)
        {
            float sum = 0.0;

            for (int i = 0; i < 4; ++i)
            {
                sum += m1.e[row][i] * m2.e[i][col];
            }

            result.e[row][col] = sum;
        }
    }

    return result;
}

// v * m
inline Point operator*(Point v, Matrix m)
{
    Point result;

    for (int col = 0; col < 4; ++col)
    {
        float sum = 0.0;

        for (int row = 0; row < 4; ++row)
        {
            sum += v.e[row] * m.e[row][col];
        }

        result.e[col] = sum;
    }

    return result;
}


#define MATRIX_H
#endif