main.cpp

#include <iostream>
#include <fstream>
#include <stdlib.h>
#include <math.h>
#include <limits>
#include <random>

#include "headers/vec3.h"
#include "headers/ray.h"
#include "headers/hitable.h"
#include "headers/sphere.h"
#include "headers/hitable_list.h"
#include "headers/camera.h"
#include "headers/material.h"
#include "headers/random_utils.h"

float max_float = std::numeric_limits<float>::max();


vec3 color(const ray& r, hitable* world, int depth) {
    hit_record rec;
    if (world->hit(r, 0.001, max_float, rec)) {
        ray scattered;
        vec3 attenuation;
        if (depth<50 && rec.mat_ptr->scatter(r,rec,attenuation,scattered)) {
            return attenuation*color(scattered,world,depth+1);
        }
        else {
            return vec3(0,0,0);
        }
    }
    else {
        vec3 unit_direction = unit_vector(r.direction());
        float t = 0.5*(unit_direction.y() + 1.0);
        return (1.0-t)*vec3(1.0, 1.0, 1.0) + t*vec3(0.5, 0.7, 1.0);
    }
}


hitable* random_scene() {
    int n=500;
    hitable **list = new hitable*[n+1];
    list[0] = new sphere(vec3(0,-1000,0), 1000, new lambertian(vec3(0.5,0.5,0.5)));
    int i=1;
    for (int a=-11; a<11; a++) {
        for (int b=-11; b<11; b++) {
            float choose_mat = random_float();
            vec3 center(a+0.9*random_float(),0.2,b+0.9*random_float());
            if ((center-vec3(4,0.2,0)).length() > 0.9) {
                if (choose_mat < 0.8) { // diffuse
                    list[i++] = new sphere(center, 0.2, 
                        new lambertian(vec3(random_float()*random_float(), random_float()*random_float(), random_float()*random_float())));
                }
                else if (choose_mat < 0.95) { // metal
                    list[i++] = new sphere(center, 0.2, 
                        new metal(vec3(0.5*(1+random_float()), 0.5*(1+random_float()), 0.5*(1+random_float())), 0.5*random_float()));
                }
                else { //glass
                    list[i++] = new sphere(center, 0.2, new dielectric(1.5));
                }
            }
        }
    }
    list[i++] = new sphere(vec3(0,1,0), 1.0, new dielectric(1.5));
    list[i++] = new sphere(vec3(-4,1,0), 1.0, new lambertian(vec3(0.4,0.2,0.1)));
    list[i++] = new sphere(vec3(4,1,0), 1.0, new metal(vec3(0.7,0.6,0.5), 0.0));

    return new hitable_list(list,i);
}






int main() {
    std::ofstream MyFile("render.ppm");
    int nx = 1000;
    int ny = 500;
    int ns = 10;
    MyFile << "P3\n" << nx << " " << ny << "\n255\n";

    // list[0] = new sphere(vec3(0,0,-1), 0.5, new lambertian(vec3(0.3,0.3,0.8)));
    // list[1] = new sphere(vec3(0,-100.5,-1), 100, new lambertian(vec3(0.8,0.8,0.0)));
    // list[2] = new sphere(vec3(1,0,-1), 0.5, new metal(vec3(0.8,0.6,0.2), 0.2));
    // list[3] = new sphere(vec3(-1,0,-1), 0.5, new dielectric(1.5));
    // list[4] = new sphere(vec3(-1,0,-1), -0.45, new dielectric(1.5));

    // // hitable* list[2];
    // // float R = cos(M_PI/4);
    // // list[0] = new sphere(vec3(-R,0,-1), R, new lambertian(vec3(0,0,1)));
    // // list[1] = new sphere(vec3(R,0,-1), R, new lambertian(vec3(1,0,0)));
    hitable* world = random_scene(); 
    // hitable* world = new hitable_list(list,5);

    vec3 lookfrom(13,2,3);
    vec3 lookat(0,0,0);
    // float dist_to_focus = (lookfrom-lookat).length();
    float dist_to_focus = 10.0;
    float aperture = 0.1;
    camera cam(lookfrom, lookat, vec3(0,1,0), 20, float(nx)/float(ny), aperture, dist_to_focus);

    for (int j=ny-1; j>=0; j--) {
        for (int i=0; i<nx; i++) {
            vec3 col(0,0,0);
            for (int s=0; s<ns; s++) {
                float u = float(i + random_float())/float(nx);
                float v = float(j + random_float())/float(ny);
                ray r = cam.get_ray(u, v);
                vec3 p = r.point_at_parameter(2.0);
                col += color(r,world,0);
            }
            col /= float(ns);
            col = vec3( sqrt(col[0]), sqrt(col[1]), sqrt(col[2]) );
            int ir = int(255.99*col[0]);
            int ig = int(255.99*col[1]);
            int ib = int(255.99*col[2]);
            MyFile << ir << " " << ig << " " << ib << "\n";
        }
    }
    delete world;

    MyFile.close();
}