Please help me with the function "World to screen"

[VDV777]

A vector is a 3D Structure that holds (or can hold) your x, y and z positions.
Vector3D is the same. It's just another name since there can be (incorrectly named) vector2D (just X and Y axis).

What is the VectorSubtract ??? It is (Enemy(x1+y1+z1)-My(x+y+z) ??? That is right?(If you give an example on the specific coordinates)

[Kenshin13]

What is the VectorSubtract ??? It is (Enemy(x1+y1+z1)-My(x+y+z) ??? That is right?(If you give an example on the specific coordinates)

It's exactly that. Some common sense would also be vital. Just like VectorAdd does addition of the vectors and DotProduct finds the dot product of two vectors.

[VDV777]

It's exactly that. Some common sense would also be vital. Just like VectorAdd does addition of the vectors and DotProduct finds the dot product of two vectors.

What is dotProduct ???It is my (x*y*z)??? It is right?
What is RefDef(I called Vect3d)??? It is :

#pragma once

#include <math.h>


    class Vect3d
    {
	public:
        float x;
        float y;
        float z;

        Vect3d(float _x, float _y, float _z)
        {
            x = _x;
            y = _y;
            z = _z;
        }

        Vect3d()
        {
        }

        float length()
        {
			return (float)sqrt(x * x + y * y + z * z);
        }

        float dotproduct(Vect3d dot)
        {
            return (x * dot.x + y * dot.y + z * dot.z);
        }

    };

		
    class PlayerDataVec
    {
		public:
        float xMouse;
        float yMouse;
        
        float xPos;
        float yPos;
        float zPos;
       
        
        
        
       

        Vect3d VecCoords()
        {
			Vect3d vec(xPos, yPos, zPos);
            return vec;
        }
    };

It is right????