godot/core/math/camera_matrix.h

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/*  camera_matrix.h                                                      */
/*************************************************************************/
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
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#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