Camera Question

  // Assuming you have yaw, pitch and roll in radians

// Yaw : Rotation right and left ( around the Up axis )

// Pitch : Rotation up and down ( around the Right axis )

// Roll : Rotation around the forward axis

// Here, I'll perform the rotations in the order : Yaw Pitch Roll

	D3DXMatrixRotationAxis( &yawMatrix,&upVec,yaw );
	D3DXVec3TransformCoord( &forwardVec,&forwardVec,&yawMatrix );
	D3DXVec3TransformCoord( &rightVec,&rightVec,&yawMatrix );

	D3DXMatrixRotationAxis( &pitchMatrix,&rightVec,pitch );
	D3DXVec3TransformCoord( &forwardVec,&forwardVec,&pitchMatrix );
	D3DXVec3TransformCoord( &upVec,&upVec,&pitchMatrix );

	D3DXMatrixRotationAxis( &rollMatrix,&forwardVec,roll );
	D3DXVec3TransformCoord( &upVec,&upVec,&rollMatrix );
	D3DXVec3TransformCoord( &rightVec,&rightVec,&rollMatrix );  

  
CCamera::CCamera()
{
	LookAt(D3DXVECTOR3(0.0f, 0.0f, 0.0f), D3DXVECTOR3(0.0f,0.0f,1.0f), D3DXVECTOR3(0.0f,1.0f,0.0f));
	Update();
}

// Build new translation matrix

void CCamera::Move(D3DXVECTOR3 vNewPosition)
{
	m_vPosition = vNewPosition;
	m_bNeedsUpdate = TRUE;
}

void CCamera::MoveRel(D3DXVECTOR3 vDeltaPosition)
{
	m_vPosition += vDeltaPosition;
	m_bNeedsUpdate = TRUE;
}

void CCamera::Rotate(D3DXQUATERNION qNewOrientation)
{
	m_qOrientation = qNewOrientation;
	m_bNeedsUpdate = TRUE;
}

// Build new rotation quaternion

void CCamera::Rotate(D3DXVECTOR3 vNewRotation)
{
	D3DXQuaternionRotationYawPitchRoll(&m_qOrientation,vNewRotation.y, vNewRotation.x, vNewRotation.z);
	m_bNeedsUpdate = TRUE;
}

void CCamera::RotateRel(D3DXVECTOR3 vDeltaRotation)
{
	// This will rotate about the camera''s current rotational position.

	D3DXQUATERNION qTemp;
	D3DXQuaternionRotationYawPitchRoll(&qTemp, vDeltaRotation.y, vDeltaRotation.x, vDeltaRotation.z);
	
	// Now rotate current orientation by new rotation.

	m_qOrientation *= qTemp;
	m_bNeedsUpdate = TRUE;
}

// Move forward along current vector

void CCamera::MoveForward(float Dist)
{
	D3DXMATRIX matTemp;
	D3DXVECTOR3 vForward(0.0f,0.0f,-1.0f);

	D3DXMatrixRotationQuaternion(&matTemp, &m_qOrientation);
	D3DXMatrixTranspose(&matTemp, &matTemp);
    D3DXVec3TransformCoord(&vForward, &vForward, &matTemp);
		
	// update location

	m_vPosition -= vForward * Dist;
	m_bNeedsUpdate = TRUE;
	
}

void CCamera::LookAt(D3DXVECTOR3 vEye, D3DXVECTOR3 vAt, D3DXVECTOR3 vUp)
{
	D3DXMATRIX matTemp;
	  
	// Set up rotation matrix

	D3DXMatrixLookAtLH(&matTemp, &vEye, &vAt, &vUp);
	  
	m_vPosition = vEye;

	// Get the orientation

	D3DXQuaternionRotationMatrix(&m_qOrientation, &matTemp); 
	  
	m_bNeedsUpdate = TRUE;
}

void CCamera::Update()
{
    D3DXMATRIX	    matRotation;
	D3DXMATRIX      matTranslation;
    
	// Set translation from position vectors (use opposite since this is camera)

	D3DXMatrixTranslation(&matTranslation, -m_vPosition.x, -m_vPosition.y, -m_vPosition.z);
		    
	// Create a rotation matrix from orientation quaternion

	D3DXMatrixRotationQuaternion(&matRotation, &m_qOrientation);

	// Create the view matrix by rotating then translating

	D3DXMatrixMultiply(&m_matView, &matTranslation, &matRotation);

	m_bNeedsUpdate = FALSE;
}

D3DXMATRIX *CCamera::GetViewMatrix()
{
	if(m_bNeedsUpdate == TRUE) Update();
	return &m_matView;
}