Thinhole类声明和实现

Thinhole类说白了就是在眼睛处，放一个放大镜。就像我们平时用放大镜观察物体一样。这样实现的效果的是，周围会模糊。原理书上都说的很清楚了，我把算法截图下来了。这个应用我猜测是在竞技游戏比如csgo中，狙击开镜后效果。具体等之后开发游戏时，再测试一下。如下：

类声明：

#pragma once
#ifndef __THINLENS_HEADER__
#define __THINLENS_HEADER__

#include "camera.h"

class Sampler;

class Thinlens :public Camera {
public:
	Thinlens();
	~Thinlens();
	Thinlens(const Thinlens& tl);
	void set_view_distance(const ldouble a);
	void set_focal_distance(const ldouble a);//这个是放大镜的系数，我默认是取0.8，因为我用的物体是1个像素，比较小。
	void set_lens_radius(const ldouble rad);//放大镜的半径
	void set_zoom(const ldouble factor);//缩放
	void set_angle(const ldouble deg);//旋转角
	void set_sampler(Sampler* const sampler);//随机采样数组，实现模糊效果
	Vector3 ray_direction(const Point3& pixel_point, const Point3& lens_point) const;
	virtual Camera* clone() const;
	virtual void render_scene(World& w);
	Thinlens& operator=(const Thinlens& tl);
private:
	ldouble lens_radius, d, f, zoom;
	Sampler* sampler;
};
#endif

类实现

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

Thinlens::Thinlens()
    :Camera(), lens_radius(0.5), f(0.8), d(1), zoom(1), sampler(nullptr) {}

Thinlens::~Thinlens() {
    if (sampler)
        delete sampler;
}

Thinlens::Thinlens(const Thinlens& tl)
    :Camera(tl), lens_radius(tl.lens_radius), f(tl.f), d(tl.d)
    , zoom(tl.zoom), sampler(tl.sampler) {}

void Thinlens::set_view_distance(const ldouble a) {
    d = a;
}

void Thinlens::set_focal_distance(const ldouble a) {
    f = a;
}

void Thinlens::set_lens_radius(const ldouble rad) {
    lens_radius = rad;
}

void Thinlens::set_zoom(const ldouble factor) {
    zoom = factor;
}

void Thinlens::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);
}

void Thinlens::set_sampler(Sampler* const sam) {
    if (sampler) {
        delete sampler;
        sampler = nullptr;
    }
    sampler = sam;
    sampler->map_to_unit_disk();
}


Vector3 Thinlens::ray_direction(const Point3& pixel_point, const Point3& lens_point) const {
    Point3 p;
    p.x = pixel_point.x * d * f;
    p.y = pixel_point.y * d * f;
    Vector3 dir = (p.x - lens_point.x) * u + (p.y - lens_point.y) * v - f * w;
    dir.normalize();
    return dir;
}

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


void Thinlens::render_scene(World& w) {
    Ray ray;
    ViewPlane vp(w.vp);
    integer depth = 0;
    Point3 sp, pp, lp;
    w.open_window(vp.hres, vp.vres);
    vp.s = 1 / (vp.s * zoom);
	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;
                lp = sampler->sample_unit_square() * lens_radius;
                ray.o = eye + lp.x * u + lp.y * v;
                ray.d = ray_direction(pp, lp);
                color += w.tracer_ptr->trace_ray(ray);
            }
            color /= vp.nsamples;
            color *= exposure_time;
            w.display_pixel(r, c, color);
        }
}


Thinlens& Thinlens::operator=(const Thinlens& tl) {
    if (this == &tl)
        return *this;
	Camera::operator= (tl);
    lens_radius = tl.lens_radius;
    d = tl.d;
    f = tl.f;
    zoom = tl.zoom;
    sampler = tl.sampler;
    return *this;
}

需要修改的World类：

void World::build() {
	vp.set_hres(200);
	vp.set_vres(100);
	vp.set_sampler(new Hammersley());
	vp.sampler->map_to_sphere();
	tracer_ptr = new MultiSphere(this);
	Geometrics* obj = new Sphere(0, 0.5);
	obj->set_color(RGBColor(1, 0, 0));
	add_object(obj);
	obj = new Sphere(Point3(0, -100.5, 0), 100);
	obj->set_color(RGBColor(0, 0, 1));
	add_object(obj);
	Thinlens* thinlens = new Thinlens();
	thinlens->set_eye(Point3(0, 0, 1));
	thinlens->set_lookat(Point3(0));
	thinlens->set_view_distance(1.5);
	thinlens->set_sampler(new MultiJittered());//书上是采用多重采样，可以替换为其他采样。不过这个采样效果是比较好的。
	thinlens->set_angle(-45);
	//thinlens->set_zoom(2.0);
	thinlens->compute_uvw();
	set_camera(thinlens);
}

　　

测试效果图（蓝色和黑色部分已经模糊了，算法测试成功！）：