OpenGL MVP Matrix - c++

Question

I am simply trying to upgrade my code from OpenGL 1 to a new version which uses VBO and GLSL. I am trying to calculate the MVP matrix but I seem to have run into a snag. As far as I know I am calculating this correctly wrt RH system. I would like to know where it is I am going wrong?
void lookAt(Vector4f& eye, Vector4f& viewPoint, Vector4f& up) {
_viewMatrix.setIdentity();
Vector4f zaxis;
zaxis = eye - viewPoint; // forward vector
zaxis.normalize();
Vector4f xaxis;
xaxis = up.cross(zaxis); // right vector
xaxis.normalize();
Vector4f yaxis;
yaxis = zaxis.cross(xaxis);
/* OPTOMIZED APPROACH */
_viewMatrix.mat[0][0] = xaxis.x; _viewMatrix.mat[0][1] = yaxis.x; _viewMatrix.mat[0][2] = zaxis.x;
_viewMatrix.mat[1][0] = xaxis.y; _viewMatrix.mat[1][1] = yaxis.y; _viewMatrix.mat[1][2] = zaxis.y;
_viewMatrix.mat[2][0] = xaxis.z; _viewMatrix.mat[2][1] = yaxis.z; _viewMatrix.mat[2][2] = zaxis.z;
_viewMatrix.mat[0][3] = -(xaxis * eye); _viewMatrix.mat[1][3] = -(yaxis * eye); _viewMatrix.mat[2][3] = -(zaxis * eye);
}
perspective(float& FOV, float& aspect, float& nearDistance, float& farDistance) {
_projectionMatrix.setIdentity();
float rad = 3.1415926f / 180.0f;
float top = nearDistance * std::tan((FOV * rad) / 2);
float bottom = -top;
float right = top * aspect;
float left = -right;
_projectionMatrix.mat[0][0] = (2 * nearDistance) / (right - left);
_projectionMatrix.mat[1][1] = (2 * nearDistance) / (top - bottom);
_projectionMatrix.mat[2][2] = -(farDistance + nearDistance) / (farDistance - nearDistance);
_projectionMatrix.mat[2][3] = (-2 * farDistance * nearDistance) / (farDistance - nearDistance);
_projectionMatrix.mat[0][2] = (right + left) / (right - left);
_projectionMatrix.mat[1][2] = (top + bottom) / (top - bottom);
_projectionMatrix.mat[3][2] = -1;
_projectionMatrix.mat[3][3] = 0;
}
The Method for sending the data
glewInit();
_shader = ShaderManager::getInstance().addShader(vert, frag);
glUseProgram(_shader.programID);
/* PROJECTION LOCATION */
_program_Projection_Location = glGetUniformLocation(_shader.programID, "projection");
if (_program_Projection_Location == -1) {
ErrorMessage error{
"Window",
"initializeShaders",
"Projection pointer location returned -1",
false
};
Logger::getInstance().addLog(error);
}
_program_View_Location = glGetUniformLocation(_shader.programID, "view");
if (_program_View_Location == -1) {
ErrorMessage error{
"Window",
"initializeShaders",
"View Matrix pointer location returned -1",
false
};
Logger::getInstance().addLog(error);
}
/* MODEL LOCATION */
_program_Model_Location = glGetUniformLocation(_shader.programID, "model");
if (_program_Model_Location == -1) {
ErrorMessage error{
"Window",
"initializeShaders",
"Model Matrix pointer location returned -1",
false
};
Logger::getInstance().addLog(error);
}
glUniformMatrix4fv(_program_Projection_Location, 1, GL_FALSE, &_projectionMatrix.mat[0][0]);
glUniformMatrix4fv(_program_View_Location, 1, GL_FALSE, &_viewMatrix.mat[0][0]);