mat4.h

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#ifndef DQM_TRACKERREMAPPER_MAT4_H
#define DQM_TRACKERREMAPPER_MAT4_H

// helper class for matrix operations
// - 4 rows
// - 3 columns
// in math operations behaves like 4x4 matrix with 4th row equal to: [0, 0, 0, 1]
// ! it's just the minimum implementation !
class mat4 {
public:
  float data[12];

  mat4() {}

  mat4(float r00,
       float r10,
       float r20,
       float r01,
       float r11,
       float r21,
       float r02,
       float r12,
       float r22,
       float x,
       float y,
       float z) {
    data[0] = r00;
    data[1] = r10;
    data[2] = r20;

    data[3] = r01;
    data[4] = r11;
    data[5] = r21;

    data[6] = r02;
    data[7] = r12;
    data[8] = r22;

    data[9] = x;
    data[10] = y;
    data[11] = z;
  }

  mat4(const mat4& mat) {
    for (unsigned i = 0; i < 12; ++i)
      data[i] = mat[i];
  }

  mat4& operator&(const mat4& mat) {
    if (this != &mat) {
      for (unsigned i = 0; i < 12; ++i)
        data[i] = mat[i];
    }
    return *this;
  }

  mat4 operator+(const mat4& mat) const {
    mat4 tmp;
    for (unsigned i = 0; i < 12; ++i)
      tmp[i] = (*this)[i] + mat[i];

    return tmp;
  }

  mat4 operator*(float s) const {
    mat4 tmp;
    for (unsigned i = 0; i < 12; ++i)
      tmp[i] = (*this)[i] * s;

    return tmp;
  }

  float& operator[](unsigned i) { return data[i]; }

  float operator[](unsigned i) const { return data[i]; }

  void MulVec(const float* vecIn, float* vecOut) {
    for (unsigned i = 0; i < 3; ++i) {
      float temp = 0;
      for (unsigned j = 0; j < 3; ++j) {
        temp += data[3 * j + i] * vecIn[j];
      }
      vecOut[i] = temp + data[9 + i];
    }
  }
  void BuildOrthographicMatrix(float left, float right, float top, float bottom, float near, float far) {
    float rmli = 1.0f / (right - left);
    float rpl = right + left;

    float tmbi = 1.0f / (top - bottom);
    float tpb = top + bottom;

    float fmni = 1.0f / (far - near);
    float fpn = far + near;

    data[0] = 2.0f * rmli;
    data[1] = 0.0f;
    data[2] = 0.0f;

    data[3] = 0.0f;
    data[4] = 2.0f * tmbi;
    data[5] = 0.0f;

    data[6] = 0.0f;
    data[7] = 0.0f;
    data[8] = -2.0f * fmni;

    data[9] = -rpl * rmli;
    data[10] = -tpb * tmbi;
    data[11] = -fpn * fmni;
  }
};

#endif