Question

I have a camera class with two reference variables. I want to pass in two references through the constructor and assign the reference variables to these, so that if I change these in this class, the other ones I defined before (and passed in) will change too. However, I get the error:

a reference of type "D3DXMATRIX &" (not const-qualified) cannot be initialized with a value of type "D3DMATRIX"

and

error C2440: 'initializing' : cannot convert from 'D3DMATRIX' to 'D3DXMATRIX &'

here is my code:

header:

#ifndef CAMERA_H
#define CAMERA_H

#include <d3d10.h>
#include <d3dx10.h>   
#include "globals.h"
#include "direct3D.h"

class Camera
{
private:
D3DXMATRIX &matProjection, &matView;
public:
Camera(
    float fOVDeg, float nearCull, float farCull,
    float xPos, float yPos, float zPos,
    D3DMATRIX &matProjection, D3DMATRIX &matView);
void SetCamera(float fOVDeg, float nearCull, float farCull);
void AdjustCamera(float x, float y, float z);
};

#endif

source:

#include "Camera.h"

Camera::Camera(
float fOVDeg, float nearCull, float farCull,
float xPos, float yPos, float zPos,
D3DMATRIX &matProjection, D3DMATRIX &matView) 
: matProjection(matProjection), matView(matView)
{
this->SetCamera(fOVDeg, nearCull, farCull);
this->AdjustCamera(xPos, yPos, zPos);
}

// Set the fixed properties of the 3D camera
void Camera::SetCamera(float fOVDeg, float nearCull, float farCull)
{
// create a projection matrix
D3DXMatrixPerspectiveFovLH(
    &matProjection,
    (float)D3DXToRadian(fOVDeg),    // the horizontal field of view
    (FLOAT)SCREEN_WIDTH / (FLOAT)SCREEN_HEIGHT, // aspect ratio
    nearCull,    // the near view-plane
    farCull);    // the far view-plane
}

// Set the adjustable properties of the 3D camera
void Camera::AdjustCamera(float x, float y, float z)
{
D3DXMatrixLookAtLH(&matView,
                   &D3DXVECTOR3 (x, y, z),
                   &D3DXVECTOR3 (0.0f, 0.0f, 0.0f),
                   &D3DXVECTOR3 (0.0f, 1.0f, 0.0f));
}

Obviously I am misunderstanding something fundamental. Any help would be greatly appreciated!

The errors I get are on the initialiser list in the constructor.

here is where I am instantiating the camera:

Camera* camera;
D3DMATRIX matProjection, matView;

//called once
void Initialise(HWND hWnd)
{
initD3D(hWnd);
    init_pipeline();
cube = new Cube();

level = new Level(*cube);

camera = new Camera(
    45.0f, 1.0f, 10000.0f,
    0.0f, 9.0f, 100.0f,
    matProjection, matView);

test = 0.0f;
}

Answer 1

It seems to me you are trying to initialize reference to Derived with a reference to Base, as in:

class D3DMATRIX {};
class D3DXMATRIX : public D3DMATRIX {};

class Camera {
private:
    D3DXMATRIX& m_;

public:
    Camera(D3DMATRIX& m) : m_(m) {}
};

MSVC9.0 says:

test.cpp(9) : error C2440: 'initializing' : cannot convert from 'D3DMATRIX' to 'D3DXMATRIX &'

Maybe you should have Camera constructor taking D3DXMATRIX& as parameters?