main.cpp

#include <float.h>
#include <time.h>

#include <iostream>

#include "bvh.h"
#include "camera.h"
#include "color.h"
#include "constant_medium.h"
#include "hittable_list.h"
#include "interval.h"
#include "material.h"
#include "quad.h"
#include "ray.h"
#include "rtweekend.h"
#include "sphere.h"
#include "texture.h"
#include "vec3.h"

void random_spheres() {
  /* 生成场景 */
  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());
      // 根据随机数 choose_mat 的取值大小随机生成 diffuse, metal, glass 材质的球
      if ((center - point3(4, 0.2, 0)).length() > 0.9) {
        shared_ptr<material> sphere_material;

        if (choose_mat < 0.8) {
          // diffuse, 漫反射材质, 反射光线在交点法线方向存在散射(漫反射)和衰减
          auto albedo = color::random() * color::random();
          sphere_material = make_shared<lambertian>(albedo);
          // 增加可以移动的球
          auto center2 = center + vec3(0, random_double(0, 0.5), 0);
          world.add(make_shared<sphere>(center, center2, 0.2, sphere_material));

        } else if (choose_mat < 0.95) {
          // metal, 金属材质, 反射光线在理想反射光线方向存在散射(漫反射)和衰减
          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, 玻璃材质, 反射光线存在折射,反射和衰减
          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));

  /* 设置相机和输出图像的属性 */
  camera cam;
  cam.aspect_ratio = 16.0 / 9.0;  // 图像的长宽比
  cam.image_width = 400;          // 图像的宽(像素数)
  cam.samples_per_pixel = 100;    // 每个像素的采样光线数
  cam.max_depth = 50;             // 光线的最大深度

  cam.vfov = 20;                    // 视场角
  cam.lookfrom = point3(13, 2, 3);  // 相机位置
  cam.lookat = point3(0, 0, 0);     // 相机观察的点
  cam.vup = vec3(0, 1, 0);          // 相机上方向向量

  cam.defocus_angle = 0.6;  // 模拟实际相机的散射角度(以实现景深效果)
  cam.focus_dist = 10.0;  // 模拟实际相机的理想焦距(以实现景深效果)
  auto start = clock();
  cam.render(world);
  auto finish = clock();
  std::clog << "Elapsed:" << (double)(finish - start) / (CLOCKS_PER_SEC)
            << "\n";
}

void two_spheres() {
  hittable_list world;

  auto checker =
      make_shared<checker_texture>(0.8, color(.2, .3, .1), color(.9, .9, .9));

  world.add(make_shared<sphere>(point3(0, -10, 0), 10,
                                make_shared<lambertian>(checker)));
  world.add(make_shared<sphere>(point3(0, 10, 0), 10,
                                make_shared<lambertian>(checker)));

  camera cam;

  cam.aspect_ratio = 16.0 / 9.0;
  cam.image_width = 400;
  cam.samples_per_pixel = 100;
  cam.max_depth = 50;

  cam.vfov = 20;
  cam.lookfrom = point3(13, 2, 3);
  cam.lookat = point3(0, 0, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}
void earth() {
  auto earth_texture = make_shared<image_texture>("earthmap.jpg");

  auto earth_surface = make_shared<lambertian>(earth_texture);
  auto globe = make_shared<sphere>(point3(0, 0, 0), 2, earth_surface);

  camera cam;

  cam.aspect_ratio = 16.0 / 9.0;
  cam.image_width = 400;
  cam.samples_per_pixel = 100;
  cam.max_depth = 50;

  cam.vfov = 20;
  // 这里的 lookfrom 应该为 (12,0,0) 才能和网站上的结果相同
  cam.lookfrom = point3(12, 0, 0);
  cam.lookat = point3(0, 0, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(hittable_list(globe));
}

void two_perlin_spheres() {
  hittable_list world;

  auto pertext = make_shared<noise_texture>(4);
  world.add(make_shared<sphere>(point3(0, -1000, 0), 1000,
                                make_shared<lambertian>(pertext)));
  world.add(make_shared<sphere>(point3(0, 2, 0), 2,
                                make_shared<lambertian>(pertext)));

  camera cam;

  cam.aspect_ratio = 16.0 / 9.0;
  cam.image_width = 400;
  cam.samples_per_pixel = 100;
  cam.max_depth = 50;

  cam.vfov = 20;
  cam.lookfrom = point3(13, 2, 3);
  cam.lookat = point3(0, 0, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}

void quads() {
  hittable_list world;

  // Materials
  auto left_red = make_shared<lambertian>(color(1.0, 0.2, 0.2));
  auto back_green = make_shared<lambertian>(color(0.2, 1.0, 0.2));
  auto right_blue = make_shared<lambertian>(color(0.2, 0.2, 1.0));
  auto upper_orange = make_shared<lambertian>(color(1.0, 0.5, 0.0));
  auto lower_teal = make_shared<lambertian>(color(0.2, 0.8, 0.8));

  // Quads
  world.add(make_shared<quad>(point3(-3, -2, 5), vec3(0, 0, -4), vec3(0, 4, 0),
                              left_red));
  world.add(make_shared<quad>(point3(-2, -2, 0), vec3(4, 0, 0), vec3(0, 4, 0),
                              back_green));
  world.add(make_shared<quad>(point3(3, -2, 1), vec3(0, 0, 4), vec3(0, 4, 0),
                              right_blue));
  world.add(make_shared<quad>(point3(-2, 3, 1), vec3(4, 0, 0), vec3(0, 0, 4),
                              upper_orange));
  world.add(make_shared<quad>(point3(-2, -3, 5), vec3(4, 0, 0), vec3(0, 0, -4),
                              lower_teal));

  camera cam;

  cam.aspect_ratio = 1.0;
  cam.image_width = 400;
  cam.samples_per_pixel = 100;
  cam.max_depth = 50;

  cam.vfov = 80;
  cam.lookfrom = point3(0, 0, 9);
  cam.lookat = point3(0, 0, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}
void simple_light() {
  hittable_list world;
  // perlin noise 纹理
  auto pertext = make_shared<noise_texture>(4);
  // 增加两个使用 perlin noise 纹理的球
  world.add(make_shared<sphere>(point3(0, -1000, 0), 1000,
                                make_shared<lambertian>(pertext)));
  world.add(make_shared<sphere>(point3(0, 2, 0), 2,
                                make_shared<lambertian>(pertext)));

  // 增加一个自发光的球
  auto difflight = make_shared<diffuse_light>(color(4, 4, 4));
  world.add(make_shared<sphere>(point3(0, 7, 0), 2, difflight));
  // 增加一个自发光的四边形
  world.add(make_shared<quad>(point3(3, 1, -2), vec3(2, 0, 0), vec3(0, 2, 0),
                              difflight));

  camera cam;

  cam.aspect_ratio = 16.0 / 9.0;
  cam.image_width = 400;
  cam.samples_per_pixel = 100;
  cam.max_depth = 50;
  cam.background = color(0, 0, 0);

  cam.vfov = 20;
  cam.lookfrom = point3(26, 3, 6);
  cam.lookat = point3(0, 2, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}
void cornell_box() {
  // Cornell Box 场景
  hittable_list world;

  auto red = make_shared<lambertian>(color(.65, .05, .05));
  auto white = make_shared<lambertian>(color(.73, .73, .73));
  auto green = make_shared<lambertian>(color(.12, .45, .15));
  auto light = make_shared<diffuse_light>(color(15, 15, 15));

  // 增加 Cornel Box 的墙壁
  world.add(make_shared<quad>(point3(555, 0, 0), vec3(0, 555, 0),
                              vec3(0, 0, 555), green));
  world.add(make_shared<quad>(point3(0, 0, 0), vec3(0, 555, 0), vec3(0, 0, 555),
                              red));
  world.add(make_shared<quad>(point3(343, 554, 332), vec3(-130, 0, 0),
                              vec3(0, 0, -105), light));
  world.add(make_shared<quad>(point3(0, 0, 0), vec3(555, 0, 0), vec3(0, 0, 555),
                              white));
  world.add(make_shared<quad>(point3(555, 555, 555), vec3(-555, 0, 0),
                              vec3(0, 0, -555), white));
  world.add(make_shared<quad>(point3(0, 0, 555), vec3(555, 0, 0),
                              vec3(0, 555, 0), white));

  // 在场景中增加两个四面体
  // 必须先 rotate 再 translate
  shared_ptr<hittable> box1 =
      box(point3(0, 10, 0), point3(165, 330, 165), white);
  box1 = make_shared<rotate_y>(box1, 15);
  box1 = make_shared<translate>(box1, vec3(265, 0, 295));
  world.add(box1);

  shared_ptr<hittable> box2 =
      box(point3(0, 0, 0), point3(165, 165, 165), white);
  box2 = make_shared<rotate_y>(box2, -18);
  box2 = make_shared<translate>(box2, vec3(130, 0, 65));
  world.add(box2);
  camera cam;

  cam.aspect_ratio = 1.0;
  cam.image_width = 400;
  cam.samples_per_pixel = 100;
  cam.max_depth = 10;
  cam.background = color(0, 0, 0);

  cam.vfov = 40;
  cam.lookfrom = point3(278, 278, -800);
  cam.lookat = point3(278, 278, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}

void cornell_smoke() {
  hittable_list world;

  auto red = make_shared<lambertian>(color(.65, .05, .05));
  auto white = make_shared<lambertian>(color(.73, .73, .73));
  auto green = make_shared<lambertian>(color(.12, .45, .15));
  auto light = make_shared<diffuse_light>(color(7, 7, 7));

  world.add(make_shared<quad>(point3(555, 0, 0), vec3(0, 555, 0),
                              vec3(0, 0, 555), green));
  world.add(make_shared<quad>(point3(0, 0, 0), vec3(0, 555, 0), vec3(0, 0, 555),
                              red));
  world.add(make_shared<quad>(point3(113, 554, 127), vec3(330, 0, 0),
                              vec3(0, 0, 305), light));
  world.add(make_shared<quad>(point3(0, 555, 0), vec3(555, 0, 0),
                              vec3(0, 0, 555), white));
  world.add(make_shared<quad>(point3(0, 0, 0), vec3(555, 0, 0), vec3(0, 0, 555),
                              white));
  world.add(make_shared<quad>(point3(0, 0, 555), vec3(555, 0, 0),
                              vec3(0, 555, 0), white));

  shared_ptr<hittable> box1 =
      box(point3(0, 0, 0), point3(165, 330, 165), white);
  box1 = make_shared<rotate_y>(box1, 15);
  box1 = make_shared<translate>(box1, vec3(265, 0, 295));

  shared_ptr<hittable> box2 =
      box(point3(0, 0, 0), point3(165, 165, 165), white);
  box2 = make_shared<rotate_y>(box2, -18);
  box2 = make_shared<translate>(box2, vec3(130, 0, 65));

  world.add(make_shared<constant_medium>(box1, 0.01, color(0, 0, 0)));
  world.add(make_shared<constant_medium>(box2, 0.01, color(1, 1, 1)));

  camera cam;

  cam.aspect_ratio = 1.0;
  cam.image_width = 600;
  cam.samples_per_pixel = 200;
  cam.max_depth = 50;
  cam.background = color(0, 0, 0);

  cam.vfov = 40;
  cam.lookfrom = point3(278, 278, -800);
  cam.lookat = point3(278, 278, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}
void final_scene(int image_width, int samples_per_pixel, int max_depth) {
  hittable_list boxes1;
  auto ground = make_shared<lambertian>(color(0.48, 0.83, 0.53));

  int boxes_per_side = 20;
  for (int i = 0; i < boxes_per_side; i++) {
    for (int j = 0; j < boxes_per_side; j++) {
      auto w = 100.0;
      auto x0 = -1000.0 + i * w;
      auto z0 = -1000.0 + j * w;
      auto y0 = 0.0;
      auto x1 = x0 + w;
      auto y1 = random_double(1, 101);
      auto z1 = z0 + w;

      boxes1.add(box(point3(x0, y0, z0), point3(x1, y1, z1), ground));
    }
  }

  hittable_list world;

  world.add(make_shared<bvh_node>(boxes1));

  auto light = make_shared<diffuse_light>(color(7, 7, 7));
  world.add(make_shared<quad>(point3(123, 554, 147), vec3(300, 0, 0),
                              vec3(0, 0, 265), light));

  auto center1 = point3(400, 400, 200);
  auto center2 = center1 + vec3(30, 0, 0);
  auto sphere_material = make_shared<lambertian>(color(0.7, 0.3, 0.1));
  world.add(make_shared<sphere>(center1, center2, 50, sphere_material));

  world.add(make_shared<sphere>(point3(260, 150, 45), 50,
                                make_shared<dielectric>(1.5)));
  world.add(make_shared<sphere>(point3(0, 150, 145), 50,
                                make_shared<metal>(color(0.8, 0.8, 0.9), 1.0)));

  auto boundary = make_shared<sphere>(point3(360, 150, 145), 70,
                                      make_shared<dielectric>(1.5));
  world.add(boundary);
  world.add(make_shared<constant_medium>(boundary, 0.2, color(0.2, 0.4, 0.9)));
  boundary =
      make_shared<sphere>(point3(0, 0, 0), 5000, make_shared<dielectric>(1.5));
  world.add(make_shared<constant_medium>(boundary, .0001, color(1, 1, 1)));

  auto emat =
      make_shared<lambertian>(make_shared<image_texture>("earthmap.jpg"));
  world.add(make_shared<sphere>(point3(400, 200, 400), 100, emat));
  auto pertext = make_shared<noise_texture>(0.1);
  world.add(make_shared<sphere>(point3(220, 280, 300), 80,
                                make_shared<lambertian>(pertext)));

  hittable_list boxes2;
  auto white = make_shared<lambertian>(color(.73, .73, .73));
  int ns = 1000;
  for (int j = 0; j < ns; j++) {
    boxes2.add(make_shared<sphere>(point3::random(0, 165), 10, white));
  }

  world.add(make_shared<translate>(
      make_shared<rotate_y>(make_shared<bvh_node>(boxes2), 15),
      vec3(-100, 270, 395)));

  camera cam;

  cam.aspect_ratio = 1.0;
  cam.image_width = image_width;
  cam.samples_per_pixel = samples_per_pixel;
  cam.max_depth = max_depth;
  cam.background = color(0, 0, 0);

  cam.vfov = 40;
  cam.lookfrom = point3(478, 278, -600);
  cam.lookat = point3(278, 278, 0);
  cam.vup = vec3(0, 1, 0);

  cam.defocus_angle = 0;

  cam.render(world);
}

int main(int argc, char** argv) {
  if (argc < 1) {
    std::clog << "请输入要生成的场景参数id[0-9]."
              << "\n"
              << "例如: ./RayTracingTheNextWeek 0 > image.ppm"
              << "\n";
    return -1;
  }
  int scene_id = int(argv[1][0] - '0');
  switch (scene_id) {
    case 0:
      // 随机场景
      random_spheres();
      break;
    case 1:
      // 网格纹理
      two_spheres();
      break;
    case 2:
      // 地球image纹理
      earth();
      break;
    case 3:
      // perlin noise纹理
      two_perlin_spheres();
      break;
    case 4:
      // 四边形
      quads();
      break;
    case 5:
      // 光源
      simple_light();
      break;
    case 6:
      // 基础 cornell box
      cornell_box();
      break;
    case 7:
      // 带有烟雾材质的 cornell box
      cornell_smoke();
      break;
    case 8:
      // 最终的场景
      final_scene(800, 10000, 40);
      break;
    case 9:
      // 最终的场景
      final_scene(400, 250, 4);
      break;
    default:
      std::clog << "场景参数id需要在[0,9]之内."
                << "\n"
                << "例如: ./RayTracingTheNextWeek 0 > image.ppm"
                << "\n";
      return -1;
  }
  return 0;
}