Camera类定义和实现

类声明：

#pragma once
#ifndef __CAMERA_HEADER__
#define __CAMERA_HEADER__

#include "../utilities/geometry.h"

class World;

class Camera {
public:
	Camera();
	Camera(const Camera& cam);
	~Camera();
	void set_eye(const Point3& p);
	void set_lookat(const Point3& p);
	void set_up(const Vector3& v);
	void set_roll(const ldouble a);
	void set_exposure_time(const ldouble t);
	void compute_uvw();
	virtual Camera* clone() const = 0;
	virtual void render_scene(World& w) = 0;
	Camera& operator=(const Camera& cam);
protected:
	Point3 eye, lookat;
	Vector3 up, u, v, w;
	ldouble exposure_time, ra;
};

#endif　　

类实现：

#include "pch.h"
#include "camera.h"

Camera::Camera()
	:eye(0, 0, 1), lookat(0), ra(0), up(0, 1, 0), u(1, 0, 0), v(0, 1, 0), w(0, 0, 1), exposure_time(1) {}

Camera::Camera(const Camera& cam)
	: eye(cam.eye), lookat(cam.lookat), ra(cam.ra), up(cam.up), 
	u(cam.u), v(cam.v), w(cam.w), exposure_time(cam.exposure_time) {}

Camera::~Camera() {}

void Camera::set_eye(const Point3& p) {
	eye = p;
}

void Camera::set_lookat(const Point3& p) {
	lookat = p;
}

void Camera::set_up(const Vector3& v) {
	up = v;
}

void Camera::set_roll(const ldouble a) {
	ra = a;
}

void Camera::set_exposure_time(const ldouble t) {
	exposure_time = t;
}

void Camera::compute_uvw() {
	w = eye - lookat;
	w.normalize();
	u = up ^ w;
	u.normalize();
	v = w ^ u;
	if (eye.x == lookat.x && eye.z == lookat.z && eye.y > lookat.y) { // camera looking vertically down
		u = Vector3(0, 0, 1);
		v = Vector3(1, 0, 0);
		w = Vector3(0, 1, 0);
	}
	if (eye.x == lookat.x && eye.z == lookat.z && eye.y < lookat.y) { // camera looking vertically up
		u = Vector3(1, 0, 0);
		v = Vector3(0, 0, 1);
		w = Vector3(0, -1, 0);
	}
}

Camera& Camera::operator=(const Camera& cam) {
	if (this == &cam)
		return *this;
	eye = cam.eye;
	lookat = cam.lookat;
	ra = cam.ra;
	up = cam.up;
	u = cam.u;
	v = cam.v;
	w = cam.w;
	exposure_time = cam.exposure_time;
	return *this;
}