////	FUNCTION: cCamera::CalculateDirectionVector()////	PURPOSE: Constructs a direction vector from the yaw and pitch values//void cCamera::CalculateDirectionVector(void){    float PitchCosine = (float)cos(Pitch);    Direction.x = (float)sin(Yaw) * PitchCosine;    // Apply pitch inversion factor    Direction.y = (float)sin(Pitch) * (InvertPitch ? 1 : -1);    Direction.z = (float)cos(Yaw) * -PitchCosine;}////	FUNCTION: cCamera::MoveCameraPosition()////	PURPOSE: Takes the keys pressed and the mouse movements and makes //			 appropriate changes to the Position and Direction vectors.//void cCamera::MoveCameraPosition(const bool Foward, const bool Back, const bool Left, const bool Right, const long MouseX, const long MouseY, const long Ticks){    // Update yaw value    Yaw += (float)MouseX / 150;    // Make sure the value doesn't get too large    if (Yaw > PI_TIMESTWO)    {        Yaw -= PI_TIMESTWO;    }     else if (Yaw < -PI_TIMESTWO)    {        Yaw += PI_TIMESTWO;    }    float NewAngle = Pitch + (float)MouseY / 200;        // Check the new angle is ok, stop the camera doing loops    if (NewAngle > -PI_OVERTWO && NewAngle < PI_OVERTWO)    {        Pitch = NewAngle;    }    // Compute direction vector using the yaw and pitch values    CalculateDirectionVector();    // Vector to hold the direction that the viewing position will move    cVector MoveDirection;    // These just move the position towards the direction being looked at    if (Foward)    {        MoveDirection.x += Direction.x;        MoveDirection.y += Direction.y;        MoveDirection.z += Direction.z;    }    if (Back)    {        MoveDirection.x -= Direction.x;        MoveDirection.y -= Direction.y;        MoveDirection.z -= Direction.z;    }    if (Left)    {        MoveDirection.x += Direction.z;        MoveDirection.z -= Direction.x;    }    if (Right)    {        MoveDirection.x -= Direction.z;        MoveDirection.z += Direction.x;    }    // Make the vector unit length before scaling    MoveDirection.Normalize();    // Scale vector by scale factor    MoveDirection = MoveDirection * (Ticks * MovementSpeed);    // Update position    Position.x += MoveDirection.x;    Position.y += MoveDirection.y;    Position.z += MoveDirection.z;}////	FUNCTION: cCamera::SetCameraMatrix()////	PURPOSE: Calls the gluLookAt function with the position and direction values//void cCamera::SetCameraMatrix(void){    // Do camera transformation    gluLookAt(Position.x, Position.y, Position.z, // Position              Position.x + Direction.x,    // Add position and direction vectors              Position.y + Direction.y,    // to get point being looked at              Position.z + Direction.z,              0.0f, 1.0f, 0.0f);           // Standard world up vector}