main.cpp

#include<iostream>
#include"rtweekend.h"
#include"color.h"
#include"hittable_list.h"
#include"sphere.h"
#include"camera.h"
#include"material.h"

using std::cin;
using std::cout;


color ray_color(const ray& r,const hittable& world,int depth){
    hit_record rec;

    if(depth <=0)
       return color(0,0,0);

    if(world.hit(r,0.001,infinity,rec)){
        ray scattered;
        color attenuation;
        if (rec.mat_ptr->scatter(r, rec, attenuation, scattered))
            return attenuation * ray_color(scattered, world, depth-1);
        return color(0,0,0);
    }

    vec3 unit_direction =unit_vector(r.direction());
    auto t=0.5*(unit_direction.y()+1.0);
    return (1.0-t)*color(1.0,1.0,1.0)+t*color(0.5,0.8,1.0);
    //线性插值             white               purple
}

hittable_list random_scene(){
    hittable_list world;

    auto ground_material = make_shared<lambertian>(color(0.5, 0.5, 0.5));
    world.add(make_shared<sphere>(point3(0,-1000,0), 1000, ground_material));

    for (int a = -11; a < 11; a++) {
        for (int b = -11; b < 11; b++) {
            auto choose_mat = random_double();
            point3 center(a + 0.9*random_double(), 0.2, b + 0.9*random_double());

            if ((center - point3(4, 0.2, 0)).length() > 0.9) {
                shared_ptr<material> sphere_material;

                if (choose_mat < 0.8) {
                    // diffuse
                    auto albedo = color::random() * color::random();
                    sphere_material = make_shared<lambertian>(albedo);
                    world.add(make_shared<sphere>(center, 0.2, sphere_material));
                } else if (choose_mat < 0.95) {
                    // metal
                    auto albedo = color::random(0.5, 1);
                    auto fuzz = random_double(0, 0.5);
                    sphere_material = make_shared<metal>(albedo, fuzz);
                    world.add(make_shared<sphere>(center, 0.2, sphere_material));
                } else {
                    // glass
                    sphere_material = make_shared<dielectric>(1.5);
                    world.add(make_shared<sphere>(center, 0.2, sphere_material));
                }
            }
        }
    }

    auto material1 = make_shared<dielectric>(1.5);
    world.add(make_shared<sphere>(point3(0, 1, 0), 1.0, material1));

    auto material2 = make_shared<lambertian>(color(0.4, 0.2, 0.1));
    world.add(make_shared<sphere>(point3(-4, 1, 0), 1.0, material2));

    auto material3 = make_shared<metal>(color(0.7, 0.6, 0.5), 0.0);
    world.add(make_shared<sphere>(point3(4, 1, 0), 1.0, material3));

    return world;
}

int main(){
    freopen("rayimage.ppm","w",stdout);

    const auto aspect_ratio = 3.0 / 2.0;
    const int image_width = 1200;
    const int image_height = static_cast<int>(image_width / aspect_ratio);
    const int samples_per_pixel = 500;
    const int max_depth = 50;

    auto world = random_scene();

    point3 lookfrom(13,2,3);
    point3 lookat(0,0,0);
    vec3 vup(0,1,0);
    auto dist_to_focus = 10.0;
    auto aperture = 0.1;

    camera cam(lookfrom, lookat, vup, 20, aspect_ratio, aperture, dist_to_focus);
   
    cout<<"P3"<<std::endl<<image_width<<" "<<image_height<<std::endl<<"255"<<std::endl;
    for (int j = image_height - 1; j >= 0; --j) {
        std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;
		for (int i = 0; i < image_width; ++i) {
            color pixel_color(0,0,0);
            for(int s=0;s<samples_per_pixel;s++){
			  double u = (i+random_double()) / (image_width - 1);       
        	  double v = (j+random_double()) / (image_height - 1);
			  ray r = cam.get_ray(u,v);
			  pixel_color+=ray_color(r,world,max_depth);
            }
			write_color(cout, pixel_color,samples_per_pixel);
		}
	}

    std::cerr << "\nDone.\n";
}