Spherical类定义和实现

此类是一个全景摄像机视角，书上介绍了详细原理。直接给实现代码。

类声明：

#pragma once
#ifndef __SPHERICAL_HEADER__
#define __SPHERICAL_HEADER__

#include "camera.h"

class Spherical :public Camera {
public:
	Spherical();
	~Spherical();
	Spherical(const Spherical& sp);
	void set_fov(const ldouble hfov, const ldouble vfov);
	void set_angle(const ldouble deg);
	Vector3 ray_direction(const Point3& pp, const integer hres, const integer vres, const ldouble s) const;
	virtual Camera* clone() const;
	virtual void render_scene(World& w);
	Spherical& operator=(const Spherical& sp);
private:
	ldouble lambda_max, psi_max;
};
#endif

类实现：

#include "pch.h"
#include "spherical.h"
#include "../utilities/world.h"
#include "../utilities/viewplane.h"
#include "../samplers/sampler.h"
#include "../tracers/tracer.h"

Spherical::Spherical() :Camera(), lambda_max(180), psi_max(180) {}

Spherical::~Spherical() {}

Spherical::Spherical(const Spherical& sp) : Camera(sp), lambda_max(sp.lambda_max), psi_max(sp.psi_max) {}

void Spherical::set_fov(const ldouble hfov, const ldouble vfov) {
	lambda_max = hfov / 2;
	psi_max = vfov / 2;
}

void Spherical::set_angle(const ldouble deg) {
	ldouble rad = radian(deg);
	up = Point3(std::cos(rad) * up.x - std::sin(rad) * up.y,
		std::sin(rad) * up.x + std::cos(rad) * up.y, up.z);
}

Vector3 Spherical::ray_direction(const Point3& pp, const integer hres, const integer vres, const ldouble s) const {
	Point3 pn(2.0 / (s * hres) * pp.x, 2.0 / (s * vres) * pp.y, 0);
	ldouble lambda = pn.x * radian(lambda_max),
		psi = pn.y * radian(psi_max);
	ldouble phi = M_PI - lambda,
		theta = 0.5 * M_PI - psi;
	ldouble sin_phi = std::sin(phi), cos_phi = std::cos(phi), sin_theta = std::sin(theta), cos_theta = std::cos(theta);
	Vector3 dir = sin_theta * sin_phi * u + cos_theta * v + sin_theta * cos_phi * w;
	return dir;
}

Camera* Spherical::clone() const {
	return new Spherical(*this);
}

void Spherical::render_scene(World& w) {
	Ray ray;
	ViewPlane vp(w.vp);
	integer depth = 0;
	Point3 sp, pp;
	w.open_window(vp.hres, vp.vres);
	ray.o = eye;
	vp.s = 1 / vp.s;
	for (integer r = vp.vres - 1; r >= 0; r--)//render from left-corner to right-corner
		for (integer c = 0; c < vp.hres; c++) {
			RGBColor color;
			for (integer p = 0; p < vp.nsamples; p++) {
				sp = vp.sampler->sample_unit_square();
				pp.x = (c - 0.5 * vp.hres + sp.x) * vp.s;
				pp.y = (r - 0.5 * vp.vres + sp.y) * vp.s;
				ray.d = ray_direction(pp, vp.hres, vp.vres, vp.s);
				color += w.tracer_ptr->trace_ray(ray);
			}
			color /= vp.nsamples;
			color *= exposure_time;
			w.display_pixel(r, c, color);
		}
}

Spherical& Spherical::operator=(const Spherical& sp) {
	if (this == &sp)
		return*this;
	Camera::operator=(sp);
	lambda_max = sp.lambda_max;
	psi_max = sp.psi_max;
	return *this;
}

测试效果图（等之后加了材质后，再看看效果）：