text: /*************************************************************************/
  /*  camera_matrix.h                                                      */
  /*************************************************************************/
  /*                       This file is part of:                           */
  /*                           GODOT ENGINE                                */
  /*                    http://www.godotengine.org                         */
  /*************************************************************************/
  /* Copyright (c) 2007-2016 Juan Linietsky, Ariel Manzur.                 */
  /*                                                                       */
  /* Permission is hereby granted, free of charge, to any person obtaining */
  /* a copy of this software and associated documentation files (the       */
  /* "Software"), to deal in the Software without restriction, including   */
  /* without limitation the rights to use, copy, modify, merge, publish,   */
  /* distribute, sublicense, and/or sell copies of the Software, and to    */
  /* permit persons to whom the Software is furnished to do so, subject to */
  /* the following conditions:                                             */
  /*                                                                       */
  /* The above copyright notice and this permission notice shall be        */
  /* included in all copies or substantial portions of the Software.       */
  /*                                                                       */
  /* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
  /* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
  /* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
  /* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
  /* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
  /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
  /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
  /*************************************************************************/
  #ifndef CAMERA_MATRIX_H
  #define CAMERA_MATRIX_H
  
  #include "transform.h"
  /**
  	@author Juan Linietsky <reduzio@gmail.com>
  */
  
  
  
  struct CameraMatrix {
  
  	enum Planes {
  		PLANE_NEAR,
  		PLANE_FAR,
  		PLANE_LEFT,
  		PLANE_TOP,
  		PLANE_RIGHT,
  		PLANE_BOTTOM
  	};
  
   	float matrix[4][4];
  
  
  	void set_identity();
  	void set_zero();
  	void set_light_bias();
  	void set_perspective(float p_fovy_degrees, float p_aspect, float p_z_near, float p_z_far,bool p_flip_fov=false);
  	void set_orthogonal(float p_left, float p_right, float p_bottom, float p_top,  float p_znear, float p_zfar);
  	void set_orthogonal(float p_size, float p_aspect, float p_znear, float p_zfar,bool p_flip_fov=false);
  	void set_frustum(float p_left, float p_right, float p_bottom, float p_top, float p_near, float p_far);
  
  	static float get_fovy(float p_fovx,float p_aspect) {
  
  		return Math::rad2deg(Math::atan(p_aspect * Math::tan(Math::deg2rad(p_fovx) * 0.5))*2.0);
  	}
  
  	float get_z_far() const;
  	float get_z_near() const;
  	float get_aspect() const;
  	float get_fov() const;
  
  	Vector<Plane> get_projection_planes(const Transform& p_transform) const;
  
  	bool get_endpoints(const Transform& p_transform,Vector3 *p_8points) const;
  	void get_viewport_size(float& r_width, float& r_height) const;
  
  	void invert();
  	CameraMatrix inverse() const;
  
  	CameraMatrix operator*(const CameraMatrix& p_matrix) const;
  
  	Plane xform4(const Plane& p_vec4);
  	_FORCE_INLINE_ Vector3 xform(const Vector3& p_vec3) const;
  
  	operator String() const;
  
  	void scale_translate_to_fit(const AABB& p_aabb);
  	void make_scale(const Vector3 &p_scale);
  	operator Transform() const;
  
  	CameraMatrix();
  	CameraMatrix(const Transform& p_transform);
  	~CameraMatrix();
  
  };
  
  Vector3 CameraMatrix::xform(const Vector3& p_vec3) const {
  
  	Vector3 ret;
  	ret.x = matrix[0][0] * p_vec3.x + matrix[1][0] * p_vec3.y + matrix[2][0] * p_vec3.z + matrix[3][0];
  	ret.y = matrix[0][1] * p_vec3.x + matrix[1][1] * p_vec3.y + matrix[2][1] * p_vec3.z + matrix[3][1];
  	ret.z = matrix[0][2] * p_vec3.x + matrix[1][2] * p_vec3.y + matrix[2][2] * p_vec3.z + matrix[3][2];
  	float w = matrix[0][3] * p_vec3.x + matrix[1][3] * p_vec3.y + matrix[2][3] * p_vec3.z + matrix[3][3];
  	return ret/w;
  }
  
  #endif
  