#ifndef Quaternion_h
#define Quaternion_h

#include "Vector.h"

struct quaternion
{
	double x, y, z, w;
};

quaternion conjugate(quaternion);
quaternion mult(quaternion, quaternion);

#endif
  

  
#include "Quaternion.h"

quaternion conjugate(quaternion quat)
{
	quat.x = -quat.x;
	quat.y = -quat.y;
	quat.z = -quat.z;
	return quat;
}

quaternion mult(quaternion quat1, quaternion quat2)
{
	quaternion temp;

	temp.x = quat1.x * quat2.w + quat1.w * quat2.x + 
			 quat1.y * quat2.z - quat1.z * quat2.y;
	temp.y = quat1.y * quat2.w + quat1.w * quat2.y +
			 quat1.z * quat2.x - quat1.x * quat2.z;
	temp.z = quat1.z * quat2.w + quat1.w * quat2.z +
			 quat1.x * quat2.y - quat1.y * quat2.x;
	temp.w = quat1.w * quat2.w - quat1.x * quat2.x -
			 quat1.y * quat2.y - quat1.z * quat2.z;

	return temp;
}
  

  
void Camera::RotateCamera(double Angle, double x, double y, double z)
{
	quaternion temp, quat_view, result;

	temp.x = x * sin((Angle * PI)/360);
	temp.y = y * sin((Angle * PI)/360);
	temp.z = z * sin((Angle * PI)/360);
	temp.w = cos((Angle * PI)/360);

	quat_view.x = View.x;
	quat_view.y = View.y;
	quat_view.z = View.z;
	quat_view.w = 1;

	result = mult(mult(temp, quat_view), conjugate(temp));

	View.x = result.x;
	View.y = result.y;
	View.z = result.z;
}

void Camera::SetViewByMouse(void)
{
	int MouseX, MouseY;
	int MiddleX = SCREENWIDTH/2;
	int MiddleY = SCREENHEIGHT/2;
	Vector MouseDirection(0, 0, 0);
	static double CurrentRotationX = 0.0;

	SDL_GetMouseState(&MouseX, &MouseY);

	if((MouseX == MiddleX) && (MouseY == MiddleY))
		return;

	SDL_WarpMouse(MiddleX, MiddleY);

	MouseDirection.x = (MiddleX - MouseX)/MouseSensitivity; 
	MouseDirection.y = (MiddleY - MouseY)/MouseSensitivity;
	
	CurrentRotationX -= MouseDirection.y;

	if(CurrentRotationX >= 1.0)
		CurrentRotationX = 1.0;
	else if(CurrentRotationX <= -1.0)
		CurrentRotationX = -1.0;
	else
	{
		Vector Axis = CrossProduct(View - Position, Up);
		Axis = Normalize(Axis);

		RotateCamera(MouseDirection.x, 0, 1, 0);
		RotateCamera(MouseDirection.y, 1, 0, 0);
	}
}